Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/08—Anti-corrosive paints

Definitions

• the invention relates to a non-lead and chromate-free formulation for anti-corrosion paints.
• metallic objects can be protected against corrosion by covering them with a metallic, inorganic or organic protective layer.
• the organic protective layers are provided with special pigments and / or fillers to increase their corrosion protection capacity. These include red lead, zinc chromate, zinc phosphate, talc, graphite and mica.
• organic compounds are also used as anti-corrosion pigments alone or in combination with inorganic pigments and fillers. Such organic compounds are, for example, benzidine phosphate, benzidine molybdate, benzidine hexacyanoferrate, organic phosphonic and arsonic acids and aromatic and aliphatic carboxylic acids and their salts, such as benzoates and laurates.
• the highly effective lead and chromate pigments can no longer be used for corrosion protection due to their toxic and / or carcinogenic properties.
• the pigments zinc phosphate and zinc tetraborate previously used in their place have only a comparatively low effectiveness.
• Zinc salts first require substrate corrosion, such as with iron:
• Zinc chromate clearly inferior.
• metal phthalocyanines have very good results as anti-corrosion pigments in paints on iron. The effect is exerted as a pure pigment and in combination with a conductive carrier.
• An improved formulation is the subject of EP 0 675 173 consisting of metal phthalocyanine, a conductive component, a hydroxyl ion-binding component and platelet-shaped pigments.
• the disadvantage of this combination is that the platelet-shaped pigment causes a high porosity of the paint.
• the result is that the water contaminating the paint has unhindered access to the metal surface, which accelerates corrosion.
• the invention has for its object to provide a formulation that can be incorporated in paint formulations based on conventional binders and as a primer on a wide variety of metal substrates, in particular on ferrous material surfaces, has corrosion protection properties, which with the protective effect of lead and
• Chromate pigments are comparable. This pigment preparation is said to have pronounced corrosion protection properties not only under atmospheric stress, but also in aerated aqueous media. According to the present invention, this object is achieved by a formulation comprising
• a and B each independently of one another an aromatic or cycloaliphatic radical, which can also contain heteroatoms such as S, Se, O and N, and aryl, alkyl, halogen, oxygen, sulfur or nitrogen-containing groups as additional substituents,
• R3 and R4 are H atoms or alkyl radicals
• the above-mentioned compounds characterized by the general formulas I and II, preferably phthalocyamines, tetraarylporphyrins and tetraazaannulenes, are used as chelate complex compounds (i).
• phthalocyanines metal phthalocyanines and especially iron phthalocyanine are preferred.
• compounds I and II is alkyl, preferably straight-chain or branched alkyl having 1-18 C atoms, in which also one or more CH 2 groups are represented by -CO-, -O-, -S-, - COO-, -O -CO- can be replaced so that two -O atoms are not next to each other.
• Halogen is preferably bromine or chlorine.
• the problem of the high manufacturing costs caused by the metal phthalocyanine can be countered by placing this active component on conductive carrier materials, such as e.g. Graphite, applies and therefore manages with far less of the actual active substance metal phthalocyanine with the same or even increased corrosion protection effect.
• conductive carrier materials such as e.g. Graphite
• the chelate complex compounds are present in the preparation according to the invention in a proportion of 3 to 30% by mass, preferably 15 to 25% by mass.
• the chelate complex compounds reduce oxygen, which, when dissolved in water, penetrates through the pores and defects in the coating to the metal substrate, thereby passivating the exposed metal substrate.
• the reduction of oxygen produces hydroxyl ions according to the following equation:
• the hydroxyl ion-binding materials (ii) used are preferably phosphates, in particular metaphosphates, bi- and triphosphates, silica gels, silicates, aluminosilicates, calcite and all poorly soluble metal salts which form poorly soluble basic salts or complex compounds with OH ions.
• phosphates in particular metaphosphates, bi- and triphosphates
• silica gels silicates
• aluminosilicates calcite and all poorly soluble metal salts which form poorly soluble basic salts or complex compounds with OH ions.
• Ca 3 (OH) 2 [Si 4 O 10 ] is formed from Ca [SiO 3 ] by taking up hydroxyl ions.
• Calcium metaphosphate is preferably used, which binds the hydroxyl ions formed during the reduction of the oxygen.
• the hydroxyl ion-binding material is contained in the preparation according to the invention in a proportion of 10 to 80% by mass, preferably 40 to 60% by mass.
• the formulation according to the invention additionally contains 5 to 65% by mass, preferably 15 to 55% by mass, of a conductive carbon-based pigment.
• the conductive pigment either consists of a carrier material which is coated with a conductive carbon-containing layer or the pigment is formed solely by the conductive material, such as in the case of carbon black, graphite or fluorine-doped graphite.
• Suitable carrier materials are mica, barium sulfate, glass flakes, silicon dioxide or titanium dioxide.
• Carbon-containing metal oxide layers are suitable as conductive layers.
• the conductive pigments preferably have a particle size ⁇ 30 ⁇ m, the particle shape being insignificant.
• the conductive pigments are preferably platelet-shaped or spherical.
• the conductive pigment can also be a
• the conductive pigment of the preparation according to the invention which is required for the catalyzed oxygen reduction, is better guaranteed by the conductive pigment.
• the binding of the hydroxyl ions formed during oxygen reduction prevents delamination of the coating from the metal substrate, so that there is no under-film corrosion (under-rusting in the case of iron materials).
• the preparation according to the invention is produced from the individual components using the machines customary in the pigment and paint industry, such as sand or pearl mills, ball mills and roller mills, in practice-oriented grinding fineness and dispersed in paint formulations based on customary binders.
• the individual components can also be successively dispersed in the binder.
• binders are alkyd resins, polyurethanes, chlorinated rubber or melamine resins, which are present in the paint formulations in an amount of 35 to 55% by mass.
• the paint formulation can also contain all the usual auxiliaries and fillers. Desiccants, dispersants, leveling agents, anti-settling agents, adhesives or thixotropic agents should be mentioned in particular. Solvents may also be present in the formulation in a proportion of 10 to 20% by mass. The solvent must be properly matched to the respective binder. Common solvents are butyl acetates, xylenes and paraffinic hydrocarbon mixtures in the boiling range from 120 to 180 ° C.
• the formulation according to the invention is used for paint formulations which are applied as a primer on a wide variety of metal substrates, in particular on iron material surfaces. After completion of film formation under atmospheric stress or exposure in aerated aqueous media, the primer is characterized by pronounced corrosion protection properties.
• the formulation according to the invention fulfills all requirements placed on corrosion protection properties.
• Another advantage of the formulation according to the invention is that it can also be used in paint formulations which contain zinc phosphate, and the primers produced therewith are even significantly superior in their corrosion protection properties to those pigmented with zinc chromate.
• Iron phthalocyanine 4.4 mass% carbon black (Printex L, Degussa) 4.4 mass% Ca-m-phosphate 17.5 mass% Zn-m-phosphate 8.7 mass% resin solution, 60% in xylene 48 , 7 mass% (air and heat drying short oil alkyd resin) butyl acetate + Shellsol D 14.6 mass% (hydrocarbon mixture) siccatives and auxiliaries: 1, 7 mass% Byk 410 from Byk, FRG
• Zinc white (zinc oxide) 11.63% by mass
• Drying agents and auxiliaries 0.83% by mass
• the preparations according to the invention are incorporated into binder systems by mixing and dispersing processes customary in the paint industry, the fineness of the grains being below 20 ⁇ m.
• the diluents suitable for the particular binder give the paints with the preparations according to the invention those for processing required viscosity.
• These diluents which are usually butyl acetate, xylene and paraffinic hydrocarbons in the boiling range from 120 to 180 ° C., can be found in the paint raw material tables by Karsten, published by Vincentz Verlag. In this way, three paints were produced with which test sheets from one
• a coating produced on aluminum and hot-dip galvanized steel substrate with a formulation according to Example 1 shows no signs of blistering or delamination after 12 months of outdoor exposure in accordance with DIN 53166, neither in the vicinity of the scratch nor on the other sample surface. Good adhesion is demonstrated by testing using the tear-off method:
• the break occurs predominantly not within the substrate / coating phase boundary, but within the coating (cohesive break).
• Paints with the pigment preparations according to the invention can consequently not only be used for iron materials, but, if a suitable binder is selected, also for other corrosive metals for the purpose of effective corrosion protection.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Paints Or Removers (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1997
  • 1997-05-23 DE DE19721645A patent/DE19721645A1/de not_active Withdrawn
• 1998
  • 1998-05-06 AU AU77619/98A patent/AU7761998A/en not_active Abandoned
  • 1998-05-06 CN CN98800689A patent/CN1226912A/zh active Pending
  • 1998-05-06 WO PCT/EP1998/002656 patent/WO1998053014A1/de not_active Application Discontinuation
  • 1998-05-06 US US09/230,061 patent/US6176907B1/en not_active Expired - Fee Related
  • 1998-05-06 EP EP98925539A patent/EP0915936A1/de not_active Withdrawn
  • 1998-05-06 CA CA002261586A patent/CA2261586A1/en not_active Abandoned
  • 1998-05-06 DE DE19880653T patent/DE19880653D2/de not_active Expired - Lifetime
  • 1998-05-06 JP JP10549875A patent/JP2000516297A/ja active Pending
  • 1998-05-06 KR KR1019997000492A patent/KR20000029479A/ko not_active Application Discontinuation
  • 1998-05-20 TW TW087107851A patent/TW387922B/zh active

Non-Patent Citations (1)

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