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
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/02—Polysilicates
• • 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
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/16—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers in which all the silicon atoms are connected by linkages other than oxygen atoms
• • 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
  • C09D5/082—Anti-corrosive paints characterised by the anti-corrosive pigment
  • C09D5/084—Inorganic compounds

Definitions

• the present invention relates to polysilazane-based coatings for the production of a protective coating for metal surfaces to prevent scale formation and corrosion protection at high temperatures.
• the necessary heat treatment for annealing or tempering the components in the range of about 900 to 1250 0 C to the oxidation of the metal surface and an associated discoloration.
• the formed scale, oxidation products of iron, must be removed consuming.
• DE 1803022 describes a ceramic protective coating, which avoids the formation of scale and, due to its very different from the steel thermal expansion coefficient flakes off during cooling and thus provides temporary protection. Disadvantages are u.a. the use of toxic lead compounds, the high stoving temperature, the inherent color (not transparent) and the temporary use of this protective coating. In addition, this protective coating is between 100 and 200 microns thick and thus requires a high material consumption.
• the present invention has for its object to develop a coating with which it is possible to protect metals from scaling and corrosion at high temperatures.
• the invention therefore provides a coating for metals containing at least one of the polysilazanes of the following formula, or mixtures of the two,
• n is an integer and n is such that the polysilazane has a number average molecular weight of 150 to 150,000 g / mol, and optionally a solvent and a catalyst and one or more co-binders.
• the coating according to the invention is particularly suitable for producing a protective coating for metals.
• the invention further provides for the use of the abovementioned coating comprising at least one polysilazane of the formula I and / or 2 in a formulation which, in addition to the polysilazane, if appropriate a solvent and a catalyst, contains a filler as additional constituent, as a result of which the oxidation- and corrosion-inhibiting Effect of polysilazane is further increased.
• Typical fillers may include various ceramic powders such as silicon carbide, silicon nitride, boron nitride, alumina, titanium dioxide, etc., various glass powders or carbon in the form of carbon black, graphite powder or eg nanotubes.
• the solvents are inert, aprotic solvents such as toluene, xylene, ethers, in particular n-dibutyl ether, etc.
• the co-binder may be either an organopolysilazane of Formula 3, - (SiR'R "-NR"') n - (3)
• R ', R ", R”' may be the same or different and are either hydrogen or organic radicals, with the proviso that R ', R “and R'” may not be simultaneously hydrogen and where n is so dimensioned in that the organopolysilazane has a number average molecular weight of 150 to 150,000 g / mol
• Particularly suitable solvents for the perhydropolysilazane formulation or the ABSE formulation are organic solvents which contain no water and no reactive groups (such as hydroxyl or amine groups). These are, for example, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, esters such as ethyl acetate or butyl acetate, ketones such as acetone or methyl ethyl ketone, ethers such as tetrahydrofuran or dibutyl ether, and mono- and polyalkylene glycol dialkyl ethers (glymes) or mixtures of these solvents.
• organic solvents which contain no water and no reactive groups (such as hydroxyl or amine groups). These are, for example, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, esters such as ethyl acetate or butyl acetate, ketones such as acetone or methyl ethyl ketone, ethers such as te
• Another component of the perhydropolysilazane formulation or the ABSE formulation may include additives, e.g. Viscosity of the formulation, background wetting, film formation or the Abllust influence or be organic and inorganic UV absorbers.
• the coating of the invention contains 1 to 40 wt .-% of at least one perhydropolysilazane or ABSEs of formula (1) and formula (2) or mixtures of the two, in particular 5 to 30 wt .-%, preferably 10 to 20 wt .-%, and optionally 0.001 to 5 wt .-%, preferably 0.01 to 2 wt .-% of a catalyst.
• Suitable catalysts are N-heterocyclic compounds, such as 1-methylpiperazine, 1-methylpiperidine, 4.4 1 -trimethylenedipiperidine, 4,4'-trimethylenebis (1-methylpiperidine), diazabicyclo- (2,2,2) octane, cis- 2,6-dimethylpiperazine.
• Suitable catalysts are mono-, di- and trialkylamines such as methylamine, dimethylamine, trimethylamine, phenylamine, diphenylamine and triphenylamine, DBU (1, 8-diazabicyclo (5,4,0) -7-undecene), DBN (1, 5 Diazabicyclo (4,5,0) -5-nonene), 1, 5,9-triazacyclododecane and 1, 4,7-triazazyklononane.
• DBU 8-diazabicyclo (5,4,0) -7-undecene
• DBN 1, 5 Diazabicyclo (4,5,0) -5-nonene
• 1, 5,9-triazacyclododecane 1, 4,7-triazazyklononane.
• Suitable catalysts are organic and inorganic acids such as acetic, propionic, butyric, valeric, maleic, stearic, hydrochloric, nitric, sulfuric, phosphoric, chloric and hypochlorous acid.
• Suitable catalysts are metal carboxylates of the general formula (RCOO) nM of saturated and unsaturated, aliphatic or alicyclic C 1 -C 22 carboxylic acids and metal ions such as Ni, Ti, Pt, Rh, Co, Fe, Ru, Os, Pd, Ir, and AI; n is the charge of the metal ion.
• Suitable catalysts are acetylacetonate complexes of metal ions such as Ni, Pt, Pd, Al and Rh.
• Suitable catalysts are metal powders such as Au, Ag, Pd or Ni with a particle size of 20 to 500 nm.
• Suitable catalysts are peroxides such as hydrogen peroxide, metal chlorides and organometallic compounds such as ferrocenes and zirconocenes.
• Coating with the polysilazane formulation may be by methods commonly used in the paint industry. These may be, for example, spraying, diving or flooding. Subsequently, a thermal aftertreatment can be done to cure the coating to accelerate. Depending on the polysilazane formulation used and, if appropriate, the catalyst, the curing takes place already at room temperature.
• the invention therefore further provides a process for producing a protective layer on a metal, wherein the polysilazane solution optionally containing catalyst and fillers is applied to the metal by suitable methods such as, for example, spraying or dipping and then cured at room temperature.
• thermolysis which is the ceramization of the
• Polysilazane coating causes. This thermolysis is carried out in a pyrolysis oven on air or other gases such as argon, nitrogen, ammonia, etc. Typically, is pyrolyzed in air.
• the heating rate is typically 3 K / min up to a temperature of 500 ° C. to 1500 ° C., preferably up to 800 ° C. to 1200 ° C., more preferably up to 1000 ° C.
• the holding time at the maximum temperature is typically 10 min. - 10 h, preferably at 30 min. to 4 h, more preferably 1 h.
• the cooling rate down to room temperature is typically 3 K / min.
• the mode of action of the polysilazane coating can be described as follows:
• 1st step Chemical bonding of the polysilazane layer to the metal substrate by reaction of the oxidic metal surface with the polysilazane (formation of a (substrate) metal O-Si (polysilazane layer) even at room temperature)
• 2nd step During the pyrolysis, the conversion of the polysilazane into silicon dioxide or a polysiloxane takes place.
• the layer thus obtained (optimum layer thickness 0.5 to 1.5 ⁇ m) adheres excellently, is flexible (substrate can be bent without the layer tearing), has excellent diffusion stability against oxygen and moisture and is chemically very stable.
• the cured coating has a thickness of 0.1 - 10 microns, preferably 0.2 to 5 microns, more preferably 0.5 to 1, 5 microns and ensures excellent protection of the surfaces from corrosion and oxidation.
• tarnishing scaling of the surface upon heating to 1000 ° C. is prevented and corrosion is also prevented for aggressive media (eg HCI atmosphere) over a very long period of time.
• the coating according to the invention was applied to various steel grades, to copper and to magnesium. It is transparent and thus does not affect the natural appearance of the metals, the coating is rather not visible at all. It offers permanent protection even under extreme conditions.
• V2A sheets (steel 1.4301, X5 CrNi 18 10 / Cr 18%, Ni 10%, Si 1%, Mn 2%, P 0.045%, S 0.03%, C ⁇ 0.07%, Fe balance) were with 20% PHPS solution (NN 120-20) at a pull rate of 0.3 m / min in air by immersion in the solution. After drying (about 30 minutes) at room temperature, the coated sheets were stored in the oven in air to 1000 0 C with a holding time of 1 h and a heating and cooling rate of 3 K / min outsourced. The oxidation test can be repeated several times, without a scaling of the steel can be seen.
• V2A sheets (steel 1.4301, X5 CrNi 18 107 Cr 18%, Ni 10%, Si 1%, Mn 2%, P
• the oxidation test can be repeated several times, without a scaling of the steel can be seen.
• Example 3 V2A sheets (steel 1.4301, X5 CrNi 18 10 / Cr 18%, Ni 10%, Si 1%, Mn 2%, P 0.045%, S 0.03%, C ⁇ 0.07%, Fe remainder ) were coated with 20% PHPS solution (NN 120-20) by spin coating at 300 rpm in air. After drying (about 30 min) at room temperature, the coated sheets were in the oven in air to 1000 0 C with a holding time of 10 h and a heating and cooling rate of 3 K / min outsourced.
• 20% PHPS solution N 120-20
• the oxidation test can be repeated several times, without a scaling of the steel can be seen.
• Example 4 V2A sheets (steel 1.4301, X5 CrNi 18 107 Cr 18%, Ni 10%, Si 1%, Mn 2%, P 0.045%, S 0.03%, C ⁇ 0.07%, Fe remainder) were coated with 20% ABSE solution in toluene at a pull rate of 0.5 m / min in air by immersion in the solution. After drying (about 30 minutes) at room temperature, the coated sheets were stored in the oven in air to 1000 0 C with a holding time of 1 h and a heating and cooling rate of 3 K / min outsourced. The oxidation test can be repeated several times, without a scaling of the steel can be seen.
• Example 5 St14 steel sheets (deep drawing steel) were coated with 20% PHPS solution (NN 120-20) at a pulling rate of 0.3 m / min by dipping in the solution in air. After drying (about 30 minutes) at room temperature, the coated sheets in the oven in air to 700 0 C with a holding time of 10 h and a heating and cooling rate of 3 K / min outsourced.
• 20% PHPS solution N 120-20
• St37 steel sheets (structural steel) were obtained by immersion in a suspension of 20% PHPS solution (NN 120-20) with 5 wt.% BN powder (average particle size approx. 0.7 ⁇ m) at a drawing rate of 0.3 m / min coated in air. After drying (about 30 min) at room temperature, the coated sheets were removed from the oven in air to 700 0 C with a holding time of 10 h and a heating and cooling rate of 3 K / min outsourced. There was no oxidation of the steel in the coating area.
• Example 7 Cu sheets were coated with 20% PHPS solution (NN 120-20) at a pulling rate of 0.3 m / min in air by immersion in the solution. After drying (about 30 min) at room temperature, the coated sheets were stored in the oven in air to 500 0 C with a holding time of 5 h and a heating and cooling rate of 3 K / min outsourced. The oxidation test can be repeated several times without oxidizing the surface of the Cu sheet.
• Example 1 The V2A sheets of Example 1 were mounted on a rack and transferred to a vessel whose bottom was covered with 1N HCl to a level of 1 cm. After sealing the container, the samples remained for 30

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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)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Paints Or Removers (AREA)

Applications Claiming Priority (2)

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• 2006
  • 2006-02-23 DE DE102006008308A patent/DE102006008308A1/de not_active Withdrawn
• 2007
  • 2007-01-24 TW TW096102688A patent/TW200745284A/zh unknown
  • 2007-02-12 RU RU2008137804/04A patent/RU2008137804A/ru not_active Application Discontinuation
  • 2007-02-12 BR BRPI0708167-7A patent/BRPI0708167A2/pt not_active Application Discontinuation
  • 2007-02-12 JP JP2008555668A patent/JP5374161B2/ja not_active Expired - Fee Related
  • 2007-02-12 KR KR1020087023193A patent/KR20080099332A/ko not_active Application Discontinuation
  • 2007-02-12 AU AU2007218312A patent/AU2007218312A1/en not_active Abandoned
  • 2007-02-12 CA CA002643377A patent/CA2643377A1/en not_active Abandoned
  • 2007-02-12 MX MX2008010898A patent/MX2008010898A/es unknown
  • 2007-02-12 US US12/224,361 patent/US8153199B2/en not_active Expired - Fee Related
  • 2007-02-12 WO PCT/EP2007/001171 patent/WO2007096070A1/de active Application Filing
  • 2007-02-12 CN CNA2007800064656A patent/CN101389721A/zh active Pending
  • 2007-02-12 EP EP07703403A patent/EP1989270A1/de not_active Withdrawn
• 2008
  • 2008-08-08 ZA ZA200806857A patent/ZA200806857B/xx unknown
  • 2008-08-14 IL IL193487A patent/IL193487A0/en unknown
  • 2008-08-26 NO NO20083677A patent/NO20083677L/no not_active Application Discontinuation

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