KR20010012658A - Lithium and vanadium containing sealing composition and process therewith - Google Patents

Abstract

Corrosion resistance of an article having a primary inorganic coating such as conversion coating on a metal substrate can be improved with a liquid composition containing a lithium cation and a vanadate anion. This treatment is advantageous for primary coatings formed on aluminum alloys by treating cobalt (II) cations, acetate ions, hydroxyalkyl amines and peroxides with a conversion coating forming aqueous composition prepared by reacting in aqueous solution.

Description

Lithium and vanadium-containing sealing composition and sealing method using same {LITHIUM AND VANADIUM CONTAINING SEALING COMPOSITION AND PROCESS THEREWITH}

This type of method is called " sealing process " because in some cases the effect of this method is shown theoretically as sealing the pores present during the primary coating. The presence of these pores is generally considered to be extremely powerful for coatings that occur when anodizing aluminum, for example, but the term "sealing" itself is now substantially sealed or present at the time of treatment. Irrespective of this, it has been applied to conventional coatings on metal surfaces, especially liquid coatings, which can be brought into contact with conversion coatings to improve the corrosion resistance of objects including metal surfaces and all protective coatings, and thereby methods for improving corrosion resistance. .

In this sense, the term "sealing" referred to in the present invention also includes other terms such as "passivating", "final cleaning", "post-cleaning" and the like. The sealing treatment according to the invention is particularly advantageous for surfaces which are not subjected to any further organic protective coating, such as paint, but also useful for substrates which are to be further protected in this way.

Conventionally, many sealing compositions for primary coatings are known, but in the case of aluminum substrates which have not been subjected to protective coating by a similar material containing substantial paint or organic binder, further improvement of corrosion resistance is required. .

The present invention improves the manner exerted by conventional primary coatings on metal surfaces, in particular zinc, aluminum and / or zinc and / or aluminum alloys, and more particularly aluminum and / or aluminum alloy surfaces. To compositions and methods for the same.

Accordingly, the main object of the present invention is to provide a sealing composition and a sealing method for improving the corrosion resistance in the known primary coating, especially in the absence of an organic protective coating.

Another object of the present invention is a more economical treatment method that minimizes adverse effects on the environment and does not inhibit the anticorrosive effect compared to conventional sealing materials frequently containing hexavalent chromium or other substances which easily destroy the environment. In providing.

Except where otherwise noted in the claims and Examples, all quantities expressing quantities of materials in the specification or quantities for reactions and / or conditions of use are used broadly in the term "about". You have to understand. However, it is preferable to carry out within the numerical limits mentioned. Also, unless otherwise indicated in the specification, values such as%, part, and ratio are concepts of weight or mass. "Polymer" means "oligomer", "copolymer", "terpolymer" and the like. One or a class of materials suitable or preferred for a given purpose in connection with the present invention means that two or more mixtures are likewise suitable or preferred. In chemical terminology, the description of each component refers to a component that is produced as-is in the composition or added to a combination specified in the specification in a chemical reaction between one or more newly added components and one or more components already present in the composition. However, it does not necessarily preclude unspecified chemistry between the components of the mixed mixture. An ionic component means that there is sufficient counterion present in the composition as a whole and in the materials added to the composition for electrical neutralization. Thus, a particular preferred counterion is selected from among other components explicitly specified in ionic form to the extent possible. Alternatively, these counterions may be arbitrarily selected, except for counterions which hinder the object of the present invention. "Mole" means "gram mole" and the term itself and all its grammatical variations are defined as any chemistry that exists in a stable neutral material with defined molecules, regardless of whether the reactants are ionic, neutral, unstable or hypothetical. Applicable to species and species of atoms. The terms “solution”, “soluble” and “uniformity” include not only intrinsic equilibrium solutions or homogeneous systems, but also at least 100, while the material is mechanically homogeneous and the material temperature is maintained at 18-25 ° C. It should be understood to include dispersions which do not exhibit a visually detectable tendency to cause phase separation for hours, preferably 1000 hours or more.

The sealing composition of the present invention is a homogeneous liquid composition which preferably comprises or consists essentially of water, lithium ions and vanadate anions, in particular decabanadate anions, hereinafter in decavanadate salts. PH 2 as a protonated derivative of the general formula 10 ₁₀ O _(28-i) (OH) _i- ^(6-i) , where i is an integer from 1 to 4, as well as the ions of formula V ₁₀ O ₂₈ ^-6 present And those considered to be predominantly present in aqueous solutions of ˜6. [FA Cotton and G. Wilkinson, Advanced lnorganic Chemistry, 4th Ed., (John Wiley & Sons, New York, 1980), p.712 Reference].

Optionally, the sealing composition of the present invention may contain at least one surfactant, pH adjusting component, and fluoride ion.

This sealing composition is suitable for sealing the primary coating layer containing metal and oxygen atoms, in particular cobalt and aluminum oxide, either as such or after dilution with water. The composition of the present invention may be referred to as a "working composition" if it is suitable for immediate use, and the composition of the present invention may be referred to as "concentrate", "concentrated composition" or "concentrated composition", etc., if it is preferable to use after dilution with water. You can also call these three terms. Of course, the various compositions of the present invention may be used as it is or after dilution with water, so that it may be referred to as a working composition or a concentrated composition.

The process of the present invention comprises contacting at least the composition of the present invention with a primary coating layer at a sufficient temperature for a sufficient time, followed by drying and optionally intermediate cleaning or other treatment with water after formation of the primary coating layer, and contacting with the sealing composition. Further cleaning after contact with the sealing composition prior to application, or further coating after drying, results in corrosion resistance of the treated object to at least one accelerated corrosion test or other identical object treated the same in at least one practical use. This goodness is measured, except that in this case, deionized water or at least equally purified purified water is used in the sealing composition of the invention used in the process of the invention. Additional process steps themselves include known steps which are part of the process of the invention. These other steps preferably do not include contacting the surface with a composition containing hexavalent chromium in increasing order of 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.003, 0.001 or 0.0002%. More preferably, the final protective coating system including primer coating may contain hexavalent chromium as one component. In protective coatings, such hexavalent chromium is generally moderately bound by organic binders to avoid adverse effects on the environment. Objects treated by the process of the invention also fall within the scope of the invention.

The compositions of the present invention described above which are preferred for a variety of reasons should be substantially free of the various components used in conventionally similar compositions. Specifically, the sealing composition of the present invention is a cobalt (II) cation than a hexavalent chromium, cyanide, nitrite ion, and cobalt (III) cation when directly contacted with the primary coating on the metal by the method of the present invention. It is preferable to contain a very small amount of the above components so as to contain 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.001 or 0.0002 or less in the order of increasing each of the components such as other coordination complexing agents for stabilizing.

The sealing composition of the present invention is in order of increasing the anionic form of tungsten to less than 0.033, 0.030, 0.027, 0.024, 0.021, 0.018, 0.015, 0.012, 0.009, 0.006, 0.003, 0.001, or 0.0003 per kg of the total composition It is preferable to contain (hereinafter, the unit of concentration of moles of component per kg of total composition is used for tungsten and other components of the anion type, hereinafter abbreviated as "M / kg").

Lithium ions required for the composition of the present invention are used as salts, hydroxides or oxides of lithium of sufficient solubility or those obtained by reaction with lithium metal. In the latter case, it is preferable not to use them in consideration of price and safety precautions. Do.

In general, for economic reasons, the lowest price is chosen, at least lithium hydroxide in the United States. Regardless of the source, the concentration of dissolved lithium cations in the working composition of the present invention is preferably at least 0.0040, 0.0070, 0.010, 0.020, 0.030, 0.040, 0.050, 0.060, 0.065, 0.070, or 0.072 M / kg in increasing order. More preferably, it is 0.75, 0.50, 0.30, 0.20, 0.130, 0.115, 0.105, 0.095, 0.085, 0.080, 0.077, 0.074 M / kg or less in increasing order.

Although vanadate having a certain degree of cohesion may be used to supply the dissolved vanadium atoms required in the composition of the present invention, decabanadate is most preferred. Sodium ammonium decabanadate of formula Na ₂ (NH ₄ ) ₄ V ₁₀ O ₂₈ is currently the most preferred because it is the cheapest source of decabanadate ions. When other vanadates are used, most of them are inadequate in water so it is better to select the counterion from the group consisting of alkali metal and ammonium cation. The concentration of vanadium atoms present in the vanadate ions in the sealing composition of the present invention is at least 0.00050, 0.0010, 0.0020, 0.0030, 0.0040, 0.0050, 0.0060, 0.0070, 0.0080, 0.0085, 0.0090 or 0.0092 M / kg in increasing order. It is preferable that it is more preferably 0.15, 0.10, 0.080, 0.060, 0.040, 0.030, 0.025, 0.020, 0.017, 0.014, 0.011 or 0.0095 M / kg or less in increasing order. Furthermore, at least 0.010: 1.0, 0.030: 1.0, 0.050 in order of increasing ratio of the concentration of vanadium atoms (M / kg) to the lithium cation concentration (M / kg) in the compositions of the present invention, independent of their actual concentrations. : 1.0, 0.070: 1.0, 0.080: 1.0, 0.090: 1.0, 0.100: 1.0, 0.110: 1.0, 0.120: 1.0 or 0.125: 1.0, more preferably 1.0: 1.0, 0.8: 1.0 in increasing order , 0.60: 1.0, 0.50: 1.0, 0.40: 1.0, 0.30: 1.0, 0.25: 1.0, 1.20: 1.0, 0.18: 1.0, 0.16: 1.0, 0.140: 1.0 or 0.130: 1.0 or less.

Typically the sealing composition of the present invention is good to contain an anion containing fluorine atoms, these anions of the formula F ^- simple fluoride anions, the formula HF ₂ ^{in-borate fluoroalkyl-acid} fluoride ion, the general formula BF ₄ of ions, formula MF ^-2 ₆ represents a (wherein, M is Si, Ti, Zr, Sn, Sb, or represents a Hf) metal ions, or acrylate chemistry class M'F ₆ ^-3 fluoroalkyl (where M 'is Al or Fe Fluoro metal ions may be used. Simple fluoride ions are economically desirable for no reason. Anions containing fluorine atoms may be derived from conventionally known suitable acids or salts. As mentioned above, the cation in commonly used salts should be selected from the cations of alkali metals and ammonium to minimize the risk of forming precipitates with high vanadate content. If present, the concentration of anionic fluorine atoms in the working composition of the present invention is preferably at least 0.005, 0.007, 0.009, 0.012, 0.016, 0.020, 0.030, 0.040, 0.045, 0.050, or 0.054 M / kg, more Preferably it is 0.50, 0.40, 0.30, 0.20, 0.10, 0.080, 0.070, 0.065, 0.060 or 0.056 M / kg or less in increasing order.

Independently, the ratio of the concentration (M / kg) of the anionic fluorine atom to the concentration (M / kg) of the lithium cation in the composition of the present invention is increased in order of at least 0.02: 1.0, 0.05: 1.0, 0.10: 1.0, 0.20: 1.0, 0.30: 1.0, 0.40: 1.0, 0.50: 1.0, 0.55: 1.0, 0.60: 1.0, 0.65: 1.0, 0.70: 1.0 or 0.74: 1.0, more preferably in increasing order of 10: 1.0, 5: 1.0, 3.0: 1.0, 2.0: 1.0, 1.7: 1.0, 1.5: 1.0, 1.3: 1.0, 1.1: 1.0, 0.97: 1.0, 0.93: 1.0, 0.89: 1.0, 0.85: 1.0, 0.81: 1.0 or 0.76: 1.0 or less.

Surfactants are added to the composition of the present invention to enhance the ability of the composition to make uniform contact with the primary coating surface. Any surfactant may be used as long as it achieves this purpose, and the surfactant may be omitted, and a quaternary amine surfactant having a molecule conforming to the following general formula is particularly preferable.

In the above formula, x and y in the molecule each represent a nonnegative integer, and R represents a hydrophobic group.

For surfactants whose molecules conform to the above formula, it is preferred that at least 2, 5, 7, 8, 10, 11 or 12 in order of increasing average sum of x and y, and more preferably in increasing order 27 , 22, 17, 15, 14, or 12 or less, in increasing order, at least 50, 60, 70, 80, 83, 86, or 89% of the R component is a saturated alkyl group, and at least 50, 60, 70, 80, 85, 90 or 95% is a linear alkyl group and is at least 8.0, 9.0, 10.0, 11.0 or 12.0 in increasing order of the average number of carbon atoms per R component, preferably 22, 20, 18.0, in increasing order 17.0, 16.0, 15.0, 14.0, or 13.0 or less. Most preferred are mixtures of hydrophobic components R derived from fatty acids resulting from saponification of neutral coconut oil. When using a surfactant, the concentration in the composition of the present invention is preferably at least 0.00010, 0.00030, 0.00050, 0.00070, 0.00080, 0.00090, 0.0010 or 0.0012 parts in order of increasing surfactant per 1000 parts of the total composition (hereinafter, other). Concentration units used for components and surfactants are usually abbreviated as "ppt"), more preferably in increasing order of 0.010, 0.008, 0.006, 0.004, 0.0030, 0.0025, 0.0020, 0.0017, or 0.0014 ppt.

Each component of the composition of the present invention described above has the ability to magnetize microorganisms introduced from the ambient atmosphere. You may add arbitrary preservatives to the composition of this invention in order to prevent the trouble resulting from such a source. Any preservative that does not impair the object of the present invention can be used in known amounts. As a preservative used for this invention, the isothiazolin-3-one component; Halogen, preferably bromine atom, more preferably at least two per molecule; And cyano components, preferably organic molecules containing at least one kind from the group consisting of at least two per molecule.

In particular, preservatives which have proven to be suitable are, for example, KATHON 886 MW sold by Rohm and Haas Corporation, KATHON®, which is 10-12% of 5-chloro-2-methyl-isothiazolin-3-one and 2 3 to 5% of methyl-isothiazolin-3-one as a preservative active ingredient, 14 to 18% of magnesium nitrate and 8 to 10% of magnesium chloride; will be. There is also a TEKTAMER® from Calgon, such as TEKTAMER 38LV, which is a 25% water dispersion of 1,2-dibromo-2,4-dicyanobutane.

In practice, it is often desirable to formulate the sealing composition of the present invention in a concentrated composition rather than as a working composition in order to reduce the transportation cost of the water-containing composition. In this case, the concentrated composition preferably contains the same components as described above for the working composition, but the concentration of each component except water is at least 2, 4, in order of increasing concentration of the above-mentioned working composition. 6, 8, 10, 20, 30, 40 or 50 times higher.

In order of increasing the pH value of the working sealing composition of the present invention is preferably at least 2.0, 3.0, 4.0, 4.5, 4.8, 5.1, 5.3 or 5.5, more preferably 8.0, 7.5, 7.0, 6.7, 6.4, 6.2 or 6.0 or less. If the pH is too high, the underlying metal is susceptible to attack, while if the pH is too low the primary coating dissolves instead of being sealed. If lithium hydroxide is used as the lithium source and any of the other necessary components described above are present in the desired amounts, then an acidifying pH adjusting component is usually required to bring the pH to at least the most desirable range. A weakly ionized acid is preferred to achieve a buffering effect within the preferred pH range, and it has been found that economical acetic acid is extremely suitable without fear of precipitating other conventional components of the sealing composition of the present invention.

The temperature of the sealing composition of the present invention during contact with the metal substrate first treated and optionally intermediate as described above is at least 15, 20, 22.0, 23.0, 24.0, 25.0 in increasing order as detailed below. , 26.0 or 26.5 ° C., mainly for economic reasons, below 90, 80, 70, 60, 50, 45, 40, 35, 30 or 28 ° C. in increasing order. At 26.7 ° C., the contact time between this sealing composition of the present invention and the previously treated and optionally intermediate metal substrate is increased in order of 0.5, 1.0, 2.0, 2.5, 3.0, 3.5, 4.0, 4.3, 4.6 or 4.9 minutes or more, mainly for economic reasons, in increasing order is 60, 30, 15, 12, 10, 8, 7.0, 6.5, 6.0, 5.7, 5.4 or 5.1 or less. As other temperature at the time of processing with this type of sealing composition, short time is preferable at high temperature, and long time is preferable at low temperature.

After the sealing process of the present invention the sealed surface is washed again with water, preferably after washing with deionized water or at least equally purified water and then drying. When heat is used to promote drying, the temperature of the metal during drying does not exceed 100, 85, 75, 66, or 60 ° C. in the order of increasing temperature, so as not to impair the quality of protection of the coating formed by the method of the present invention. Do not

Existing contacting metal surfaces, preferably cleaned and deoxygenated aluminum alloy surfaces, with primary treatment compositions prepared by reaction in aqueous solution containing or consisting essentially of water and dissolved components below It is preferable to apply the method of the present invention to the surface formed by the primary treatment.

(A) cobalt (II) cations,

(B) carboxylate anions,

(C) Species other than carboxylate anions which form more stable coordination bonds with cobalt (III) cations than cobalt (II) cations,

(D) oxidizing agents,

And any one or more of the following ingredients:

(E) Nitrate ion

(F) one component selected from the group consisting of cations of alkali metals and alkaline earth metals;

(G) fluoride anions and complex fluoride anions.

The ratio of the number of moles of component (B) to the number of moles of component (A) in the aqueous solution before reaction is 0.10-6.8 above.

Contacting the "active" metal substrate with such a primary treatment composition forms a metal substrate surface of an adhesive conversion coating containing several metal atoms and at least cobalt and oxygen atoms from the treated substrate (reacting in this manner Any metal can be referred to as "active metal" within the meaning of the following terms).

The concentration of the reacted component (a) is, in the preferred primary composition used for primary coating formation prior to the sealing treatment according to the present invention, in which the concentration of cobalt atoms increases in the order of 0.001, 0.002, 0.004, 0.008, 0.016, 0.032, 0.040, 0.045, 0.050, 0.055, 0.060, 0.063, 0.066, 0.069, 0.072, 0.074, or 0.076 M or more, preferably 0.8, 0.6, 0.4, 0.2, 0.17, 0.14, 0.11 in increasing order , 0.090, 0.085, 0.080, or 0.078M or less.

The specific counterion (s) in the salt state in which cobalt (II) is usually added in the aqueous solution in which the reaction takes place is not narrowly limited, but it is stably bound to cobalt (II) and reacts with other components in cobalt (III). Counter ions that prevent oxidation of the furnace should be avoided. However, in order to minimize the possibility of unnecessarily obstructing the required reaction, the counterion of cobalt added to the aqueous solution in which the reaction takes place is obtained from a group of nitrate ions which are relatively weak in forming complexes and carboxylate ions which are part of component (B). It is desirable to choose.

The component (b) is preferably selected from anions of unsubstituted carboxylic acids having 5, 4, 3 or 2 or more carbon atoms per molecule, more preferably in increasing order. Acetate ions are most preferred because they are much cheaper than most other carboxylates. The ratio of the number of moles of component (I) to the number of moles of component (A) in the solution before the reaction is at least 0.1: 1.0, 0.2: 1.0, 0.4: 1.0, 0.8: 1.0, 1.2: 1.0, 1.5: 1.0, 1.8: 1.0, 2.0: 1.0, 2.2: 1.0, 2.3: 1.0, 2.4: 1.0, 2.5: 1.0 or 2.6: 1.0. Preferably 6.5: 1.0, 6.0: 1.0, 5.5: 1.0, 5.0: 1.0, 4.5: 1.0, 4.0: 1.0, 3.7: 1.0, 3.4: 1.0, 3.1: 1.0, 3.0: 1.0, 2.9: 1.0, 2.8: 1.0 Or 2.7: 1.0 or less. Thus, the most preferred concentration of carboxylate ions is much larger than the cobalt (II) carboxylate itself can supply, and alkaline earth metal cations as alternative cations that act as counterions for these "excess" carboxylates. , In particular magnesium and calcium, most preferably alkali metal cations of magnesium cations, and alkali metal cations may also be used. Although possible within the scope of the present invention, it is not desirable to use carboxylic acids to supply the required amount of carboxylate ions, because using them results in a pH value of the composition of the present invention less than or equal to the most preferred values below. This is because there is a tendency to lower.

Component (C) is preferably selected from organic compounds containing at least one nitrogen atom with unshared electron pairs per molecule of the compound. Hydroxyalkyl amines, especially triethanol amines, are the most preferred ingredients of component (C). The ratio of the molar concentrations of nitrogen atoms with unshared electron pairs to the molar concentrations of component (a) present in the solution before the reaction is 0.03: 1.0, 0.06: 1.0, 0.13: 1.0, 0.20: 1.0, 0.24: 1.0 in increasing order. , 0.26: 1.0, 0.28: 1.0, 0.30: 1.0, 0.32: 1.0, 0.34: 1.0, 0.35: 1.0, or 0.36: 1.0 or more are preferred, and more preferably 2.0: 1.0, 1.75: 1.0, in increasing order, 1.50: 1.0, 1.25: 1.0, 1.00: 1.0, 0.75: 1.0, 0.60: 1.0, 0.50: 1.0, 0.45: 1.0, 0.41: 1.0, 0.39: 1.0, or 0.38: 1.0 or less.

After the addition of component (D) to the precursor solution containing only water, components (A), (B) and (C), the reaction product between these components should be sufficient. And increase ultraviolet absorption and / or color change at any wavelength within the wavelength range of 160 to 450 nanometers (hereinafter referred to simply as "nm") of the precursor mixture solution.

Conventional ambient air or other sources of oxygen gas are suitable as oxidizing agents, but at least a part of component (D) is preferred as a soluble compound including peroxide and / or superoxide components for production speed, convenience and easy process control. More preferred is peroxide, and most preferred is hydrogen peroxide (because peroxide is the cheapest and commercially available). The ratio of the molar concentration of the peroxide component present in the solution to the molar concentration of the cobalt atoms present in the solution is preferably at least 0.05: 1.0, 0.10: 1.0, 0.20: 1.0, 0.30: 1.0, 0.40 in increasing order. : 1.0, 0.45: 1.0, 0.50: 1.0, 0.55: 1.0, 0.60: 1.0, 0.65: 1.0, 0.68: 1.0, 0.71: 1.0, or 0.73: 1.0, more preferably in increasing order 10: 1.0, 7 : 1.0, 5: 1.0, 3: 1.0, 2: 1.0, 1.5: 1.0, 1.0: 1.0, 0.95: 1.0, 0.90: 1.0, 0.85: 1.0, 0.80: 1.0, 0.77: 1.0, or 0.74: 1.0 or less.

Even when peroxides are used in preparing the preferred primary compositions used to form the primary coatings prior to the sealing process according to the present invention, (1) a spray is used to contact the solution and the metal to be treated, and (2) Using a separate spray processor for the purpose of aeration in the process line where the preferred primary composition used for the primary coating prior to the sealing treatment of the present invention is circulated during use, or (3) the primary composition in this process line It is preferable that the primary composition is continuously and well aerated during use by venting with air and / or oxygen gas in the container (which is convenient when the dipping process is used).

In particular, it is preferred that nitrate ions be present from the start of the reaction in the reaction mixture reacted to produce the preferred primary composition used for the primary coating prior to the sealing treatment of the present invention, for this reason This is because more uniform primary coating was observed to form on aluminum. Therefore, the ratio of the molar concentration of nitrate ions before the reaction to the molar concentration of the cobalt atoms in the aqueous composition reacted for the preparation of the preferred composition used for the primary coating formation before the sealing treatment of the present invention is preferably In increasing order: 0.05: 1.0, 0.1: 1.0, 0.2: 1.0, 0.4: 1.0, 0.6: 1.0, 0.8: 1.0, 1.0: 1.0, 1.2: 1.0, 1.4: 1.0, 1.6: 1.0, 1.8: 1.0, 1.9 : 1.0 or 1.95: 1.0 or more, and independently, preferably 20: 1.0, 15: 1.0, 10: 1.0, 5: 1.0, 4: 1.0, 3.5: 1.0, 3.0: 1.0, 2.8: 1.0, 2.6: 1.0, 2.4: 1.0, 2.2: 1.0, 2.1: 1.0, or 2.05: 1.0 or less.

The pH value of the preferred working primary composition used for primary coating formation prior to the sealing treatment of the present invention is preferably at least 3, 4, 4.5, 5.0, 5.5, 6.0, 6.2, 6.3, 6.4 in increasing order. , 6.5, 6.6, 6.7 or 6.8, independently and preferably up to 10, 9, 8.5, 8.2, 8.0, 7.9, 7.8, 7.7, 7.6, 7.5, 7.4, 7.3 or 7.2 in increasing order. The pH values within these preferred ranges are obtained by using the above-mentioned preferred components in the preparation of the preferred composition used to form the primary coating before the sealing process of the present invention, but the pH values may be determined by other known acidic components or It can be adjusted by adding a small amount of the basic component. Cobalt containing precipitates is formed rapidly at a pH value above the preferred upper limit, thereby making the composition unsuitable for the intended use, whereas at a pH value below the preferred lower limit, cobalt (III) is destabilized to sufficiently inhibit the desirable function of the composition.

In preparing the preferred compositions used to form the primary coating prior to the sealing treatment of the present invention, other components except for the use of optional components (E) and counterions of components (A) and (B) In the absence, components (A) and (B) are first mixed in an aqueous solution, and then component (C) is added to the mixture. After mixing components (A), (B) and (C) into solution, add component (D) (except in equilibrium with aqueous solution). Since the temperature at the time of mixing is not narrowly limited, any temperature between the freezing temperature and the boiling point of the solution can be used, but all of these conditions are best balanced to bring the temperature of the solution to almost room temperature, that is, 20 to 25 ° C.

Typically, the surface of the metal substrate should be cleaned before the treatment of forming the primary coating sealed by the present invention, and if the substrate is one of metals such as aluminum and magnesium, in which a thick oxide film is naturally formed on the surface, it is known. Deoxygenation should be carried out in the manner of Preferred deoxygenation methods are described in the examples below.

The protective coating can be formed at least slightly rapidly at high temperatures within this range by using the preferred primary composition used in the primary coating formation prior to the sealing treatment of the present invention in a significant temperature range. In general, when using one of the preferred compositions described above, the preferred temperature during primary coating formation is at least 20, 25, 28, 30, 32, 34, 35, 36, or 37 ° C. in increasing order, more moderate than the best possible corrosion resistance. Preferred temperatures where it is important to accelerate coating formation are at least 40, 43, 45, 47 or 49 ° C. in increasing order. Independently generally the temperature at the time of primary coating formation when using one of the preferred compositions described above is preferably 90, 85, 80, 75, 72, 69, 67, 65, 63, 62, If the temperature is less than 61 or 60 ° C. and the highest possible corrosion resistance is required, the preferred temperatures are increased in the order of increasing, especially when the metal substrate treated by the present invention is used without paint or similar organic protective coating. It is 39 or 38 degrees C or less.

Contact between the preferred primary composition used for forming the primary coating before the sealing process according to the present invention and the metal substrate treated by the primary coating forming process can be achieved by a combination of conventional or various methods. . For example, immersion and spraying methods can all give completely satisfactory results. In general, the spraying method gives a greater opportunity by spraying oxygen in the atmosphere to participate in the coating formation reaction, or more effectively the part of the liquid primary composition adjacent to the surface treated with the liquid primary composition. Because of the mixing it is possible to achieve the required coating weight somewhat faster than dipping.

Whatever the practical reason, when spraying at 60 ° C., the preferred contact time is at least 5, 10, 20, 30, 40, 50, 60, 65, 70, 75, 80, 85 or 90 seconds in increasing order, independently Preferably it is 30, 15, 12, 10, 8, 6, 5, 4, 3, 2.5, 2.2, 2.0, 1.8, 1.7, 1.6 or 1.55 minutes or less in increasing order. Preferred contact times when immersed at 60 ° C. are at least 0.2, 0.5, 0.8, 1.0, 1.5, 2.0, 2.5, 2.8, 3.2, 3.6 or 3.9 minutes in increasing order independently, preferably in increasing order of 30, 25, 20, 15, 12, 9, 8, 7, 6, or 5 minutes. Preferred contact times when immersed at 38 ° C. are at least 2, 5, 8, 10, 11, 12, 13 or 14 minutes in increasing order, independently 60, 40, 30, 25, in increasing order 20, 18, 17 or 16 minutes or less. Contact times at other temperatures should generally be long at low temperatures and short at high temperatures.

After forming the first coating, the treated metal surface with the first coating is washed with water and then dried. In many cases, the primary coating may not be formed using the preferred compositions described above, including those containing cobalt, oxygen, and aluminum during the primary coating, but within one minute even if it can be formed, for example, by the method of WO94 / 00619. In addition to or instead of the conventional cleaning which is usually completed, it is advantageous to maintain the contact between the surface treated with the above-described primary treatment for a long time.

The total time required for this intermediate treatment is preferably at least 1.0, 2.0, 3.0, 3.5, 4.0, 4.3, 4.6 or 4.9 minutes in increasing order, independently and preferably 60, in increasing order mainly for economic reasons. 30, 20, 10, 8, 7.0, 6.5, 6.0, 5.7, 5.4 or 5.1 minutes or less. In general, it is preferable to use the intermediate treatment as an immersion method, because spraying for a relatively long time generates a large amount of waste water and increases evaporation loss of water. It is usually satisfactory with only one soak for the entire duration of the disturbance and this is also desirable because it is more economical but intermittently two or more times so that the treated substrate is not in contact with water between each soak and an immediate continuous soak. The total immersion time may be achieved by dipping. It is particularly preferable to carry out a sealing treatment containing vanadium in an amount greater than the desired amount of anionic tungsten after the intermediate treatment.

As described above, in the intermediate treatment, purified water is usually preferred, but an oxidizing agent such as nitrite ions added in the form of sodium nitrite may be included together with water if necessary. The temperature is not narrowly limited, but is usually in the range of 20 to 30 ° C, preferably 26 to 28 ° C, which is slightly higher than room temperature or room temperature.

Preferably, the primary coating sealed by the above sealing treatment comprises a metal selected from the group consisting of aluminum, cesium, cobalt, molybdenum, titanium, tungsten, vanadium, zinc and zirconium, more preferably aluminum and The total amount of metal selected from the group consisting of cobalt is contained at least 5 atomic percent, or at least 10, 15, 20 or 25 atomic percent in increasing order. These primary coatings, which are independently sealed by the above-mentioned sealing treatment, contain at least 5 atomic percent oxygen, or at least 10, 15, 20 or 25 atomic percent oxygen in increasing order.

After the intermediate treatment, sealing and drying treatment according to the primary coating need according to the present invention, the metal substrate is suitable as a substrate for paint or similar organic protective coating applied by a known method. By carrying out the most preferred primary coating, intermediate treatment and sealing treatment according to the present invention, the aluminum substrate has excellent corrosion resistance even without an organic protective coating.

The sealing composition according to the present invention may be somewhat inconsistent with the explicit description, but may be incorporated in US patents and pending US patents, namely US Patent Nos. 5,098,064 (1992, 2.18; Reghi), 5,268,042 (1993). Dolan) and 5,281,282 (1994, 1.25; Dolan); 5,342,456 (1994, 8.30; Dolan et al.) And 5,356,490 (1994, 10.18; Dolan et al.); 5,411,606 (1995, 5.2; Schriever) and 5,415,687 (1995, 5.16; Schriever); 5,427,632 (1995, 6.27; Dolan) 5,449,414 and 5,449,415 (1995, 9.12; Dolan); 5,472,984 (1995, 12.5; Schriever) and 5,487, 949 (1996, 1.30; Schriever); 5,534,082 (1996, 7.9; Dollman et al.); 5,541,994 (1996, 9.3; Schriever); And primary coatings formed by treating metal surfaces by the compositions and methods described in International Patent Application No. PCT / US94 / 13273 (designated United States of America, application date 1994, 11.23).

Furthermore, even if the scope of claims in these patents and patent applications is limited to coatings formed by drying intact, treatment with the compositions disclosed herein to form coatings and then cleaning are also possible with the sealing compositions and methods of the present invention. Preferred primary coating for sealing.

The present invention is explained in more detail according to the following non-limiting examples, comparative examples and test results. A working primary coating composition was prepared as follows. That is, 1063 g of an aqueous solution of cobalt nitrate (II) containing 13% cobalt and 670 g of magnesium acetate tetrahydrate was added to about 15 liters of deionized water, and these components were thoroughly mixed at room temperature and aeration of the liquid mixture was started. Then 131 g of 99% pure triethanolamine were added and mixed, followed by 168 g of hydrogen peroxide solution containing 35% H ₂ O ₂ .

Deionized water was added to this liquid mixture to dilute to a total volume of 30.3 liters to form a solution, and then diluted with 10 times the initial volume with deionized water to absorb 4 to 40% of UV light at a wavelength of 362 nm at a transmission path of 1 cm. Phosphorus primary coating liquid was obtained. The solution thus diluted started to heat and the aeration continued to raise the temperature of the mixture to 54 ± 1 ° C. and maintained at the operating temperature selected during use of the primary coating forming composition below.

A rectangular panel made of type 2024-T3 aluminum alloy having a size of 7.6 x 25.4 cm was used as the substrate. These substrates were processed in the following process steps. All products in these process steps are available from Henkel Surface Technologies Division of Henkel, USA.

1. RIDOLINE 53 Silicate Suppression Washing by dipping at 60 ° C for 5 minutes in an aqueous solution containing 15 g / L alkaline cleaner.

2. Wash with hot water

3. Deoxygenate by soaking for 5 minutes at 21 ° C. in an aqueous solution of DEOXDIZER 6-16 concentrate prepared according to the manufacturer's instructions.

4. Wash with cold water.

5. Immersion in said working primary coating forming composition for 4-10 minutes at said temperature depending on the thickness of said primary coating.

6. Complete contact with the working primary coating-forming composition and rinse with cold water.

7. Immersion for 5 minutes at 60 ± 1 ° C. in the sealing composition according to the invention or the comparative composition described below.

8. End contact with sealing composition and flush with cold water.

9. Drying by blowing with air and / or drying in oven at 32-66 ° C.

The sealing composition 1 according to the present invention contained each of the following components, which were added to about 900 parts of deionized water in the following order.

° Glacial acetic acid 4.54 parts

° Lithium hydroxide 1 beard 3.08 parts

° Ammonium decabanadate 1.00 parts

(Commercially available as SAVAN from Kerr-McGee Chemical)

° CHEMEEN C-12 surfactant (commercially available from Chemax, 100% PEG-12 cocamine)

° anhydrous potassium fluoride 3.2 parts

° Add deionized water to 1000 parts in total.

The sealing composition 2 which is not by this invention contained the same component as the sealing composition 1 except having omitted sodium ammonium decabanadate.

The sealing composition 3, which is also not according to the present invention, was a solution obtained by adding 7.5 g of sodium ammonium decabanadate per liter in deionized water.

The aluminum panel was subjected to a salt spray test at an angle of 6 ° to the horizontal. The results are expressed as the number of pit per panel after at least a specific exposure time. The results are shown in Table 1 below.

TABLE 1

Cobalt g per 1st coating (㎡) Number of sealing compositions used Feet per panel after salt spray 168 hours 336 hours 0.124 One none none 0.243 2 Too many feet to count Not measurable 0.121 3 10-25 Not measurable 0.122 One none none

It is clear from the results of Table 1 that the corrosion resistance of each panel treated by the present invention is extremely superior to that of each panel treated with the comparative composition.

Claims (11)

In the composition as it is or after dilution with water to contact the metal substrate to seal the first coating on the metal substrate, the composition is Water, (A ') lithium cation, and (B ') A homogeneous liquid composition containing a vanadate anion. The method of claim 1, Water, (A ') at least about 0.0040 M / kg of lithium cation, (B ′) The vanadate anion at a concentration of at least about 0.00050 M / kg and the concentration of the vanadate anion (M / kg) have a ratio of from about 0.01: 1.0 to the concentration (M / kg) of lithium cations in the same composition. About 1.0: 1.0, (C ') The concentration of the fluorine-containing anion corresponding stoichiometrically to the concentration of the fluorine atom is (a) at least about 0.005 M / kg and (b) the concentration of lithium cation in the same solution (M / kg) A composition containing a fluorine containing anion having a ratio to about 0.02: 1.0 to about 10: 1.0. The method of claim 2, Water, (A ′) lithium cations at a concentration of at least about 0.020 M / kg, (B ′) The vanadate anion at a concentration of at least about 0.0030 M / kg and the concentration (M / kg) of the vanadate anion have a ratio of from about 0.050: 1.0 to the concentration (M / kg) of the lithium cation in the same composition About 0.60: 1.0, (C ') The concentration of the fluorine-containing anion corresponding stoichiometrically to the concentration of the fluorine atom is (a) at least about 0.005 M / kg and (b) the concentration of lithium cation in the same solution (M / kg) Fluorine-containing anions having a ratio of from about 0.20: 1.0 to about 2.0: 1.0, (D ') A composition containing at least 0.00030 ppt of surfactant. The method of claim 3, Water, (A ′) lithium cations at a concentration of at least about 0.60 M / kg, (B ′) The concentration of decabanadate anion at a concentration of at least about 0.080 M / kg and the decabanadate anion (M / kg) have a ratio of about 0.10 to the concentration (M / kg) of lithium cations in the same composition: 1.0 to about 0.18: 1.0, (C ') The concentration of fluorine-containing anions corresponding stoichiometrically to the concentration of fluorine atoms is (a) at least about 0.04 M / kg, and (b) the concentration of lithium cations in the same solution (M / kg) Fluorine-containing anions having a ratio of from about 0.55: 1.0 to about 1.1: 1.0, (D ′) A composition containing at least 0.010 ppt of surfactant component, consistent with the general formula below. In the above formula, x and y each represent a non-negative integer, R represents a hydrophobic group of a saturated alkyl component, the average value of the sum of x and y of all molecules in the surfactant component is 10 to 14, and The number of carbon atoms is 9.0-14.0. In the composition as it is or after dilution with water to contact the metal substrate to seal the first coating on the metal substrate, the composition is A homogeneous liquid composition obtained by dissolving and stably dispersing water and at least one other material in pure water, or by dissolving the following components in a liquid in which both of them are dissolved and stably dispersed. (A ") when the lithium cation of at least one source, and the source of the lithium cation is not a source of vanadate anion, (B ") Vanadate anion of one or more sources. The method of claim 5, wherein the composition is prepared by dissolving and dispersing the following components in pure water or by dissolving and stably dispersing water and at least one other material. Composition. (A ″) The composition, wherein the composition comprises a lithium cation source containing a lithium cation in an amount corresponding to a lithium cation concentration of at least about 0.0040 M / kg, and wherein the source of dissolved lithium cation is not supplied to the composition The concentration of the vanadate anion in is (a) at least about 0.00050 M / kg, and (b) the ratio to the concentration (M / kg) of the lithium cation supplied to the same composition is from about 0.01: 1.0 to about 1.0: 1.0 Vanadate anions dissolved in an amount corresponding to (B ″) the vanadate anion supplied to the composition by a lithium cation source, wherein the concentration of the vanadate anion is (a) at least about 0.0030 M / kg and (b) the lithium cation supplied to the same composition A source of vanadate anion that supplies a vanadate anion having a ratio to a concentration (M / kg) of about 0.050: 1.0 to about 0.60: 1.0, and a source of dissolved lithium cation and vanadate anion is not supplied to the composition The stoichiometry of the concentration of fluorine atoms is (a) at least about 0.005 M / kg and (b) the ratio to the concentration (M / kg) of lithium cations supplied to the same solution is from about 0.02: 1.0 to about 10: 1.0 Fluorine-containing anions dissolved in theoretically corresponding amounts, In addition to the fluorine-containing anions supplied by the source of (C ″) lithium cation and vanadate anion, the concentration of fluorine atoms in the composition is (a) at least about 0.005 M / kg and (b) is supplied to the same solution A fluorine-containing anion in an amount stoichiometrically corresponding to a ratio of the concentration of lithium cations (M / kg) to from about 0.02: 1.0 to about 10: 1.0. The composition of claim 6, wherein the composition is prepared by dissolving and dispersing the following components stably in preparing the composition, or by dissolving the following components in a solution in which the two components are dissolved in water and stably dispersed. (A ") The concentration of the vanadate anion is a lithium cation source containing an amount of lithium cation corresponding to a lithium cation concentration of at least about 0.020 M / kg, and if the source of dissolved lithium cation is not supplied to the composition, A) at least about 0.0030 M / kg and (b) a ratio of the concentration (M / kg) of the lithium cation supplied to the same composition that is water soluble and / or naturally redispersed in water, from about 0.050: 1.0 to about 0.60: 1.0 Vanadate anions dissolved in an amount corresponding to (B ") In addition to the vanadate anion supplied to the composition by a lithium cation source, the composition has a concentration of vanadate anion, (a) at least about 0.0030 M / kg, (b) water soluble and / or naturally A source of vanadate anion that supplies a vanadate anion having a ratio of the concentration (M / kg) of lithium cation supplied to the same composition to be redispersed, from about 0.050: 1.0 to about 0.60: 1.0, and the dissolved lithium cation and vanadate If no source of anion is supplied to the composition, the concentration of fluorine atoms is (a) at least about 0.005 M / kg, and (b) the ratio to the concentration (M / kg) of lithium cations supplied to the same solution is about 0.20: Fluorine-containing anions dissolved in stoichiometric equivalent amounts to 1.0 to about 2.0: 1.0, (C ") together with the fluorine-containing anions supplied by the source of the lithium cation and the vanadate anion, the concentration of the fluorine-containing anion is (a) at least about 0.005 M / kg, and (b) of the lithium cation supplied to the same solution. The composition is supplied with a source of lithium cation, vanadate anion and fluorine containing anion in an amount that is stoichiometrically equivalent to a ratio of concentration (M / kg) from about 0.20: 1.0 to about 2.0: 1.0 If not at least 0.00030 ppt of surfactant, (D ″) A surfactant added to the composition in an amount of at least 0.00030 ppt with the surfactant supplied to the composition by lithium cations, vanadate anions and fluorine-containing anions. 8. The composition of claim 7, wherein the composition is prepared by dissolving the following components in water when the composition is prepared. (A ") the concentration of decabanadate anion when the source of lithium cation containing an amount of lithium cation corresponding to a lithium cation concentration of at least about 0.60 M / kg and a source of dissolved lithium cation are not supplied to the composition, (A) at least about 0.080 M / kg and (b) in the same composition, the decabana dissolved in an amount corresponding to a ratio of the concentration (M / kg) of the lithium cation to about 0.10: 1.0 to about 0.18: 1.0 Dating Anion, (B ") in addition to the decabanadate anion supplied to the composition by a lithium cation source, the concentration of decabanadate anion in the composition is (a) at least about 0.080 M / kg and (b) is supplied to the same composition The source of the decabanadate anion supplying the decabanadate anion having a ratio to the concentration (M / kg) of the lithium cation is from about 0.10: 1.0 to about 0.18: 1.0, and the source of the dissolved lithium cation and decabanadate anion The concentration of fluorine atoms, if not supplied, is (a) at least about 0.04 M / kg, and (b) the ratio to the concentration (M / kg) of lithium cations supplied to the same solution is from about 0.55: 1.0 to about 1.1: Fluorine-containing anions dissolved in stoichiometric equivalents to 1.0, (C ") together with the fluorine-containing anions supplied by the source of the lithium cation and the decabanadate anion, the concentration of the fluorine atom is (a) at least about 0.04 M / kg, and (b) of the lithium cation supplied to the same solution. A source of fluorine-containing anions supplied in the composition with a quantity of fluorine-containing anions stoichiometrically corresponding to a ratio of concentration (M / kg) of about 0.55: 1.0 to about 1.1: 1.0, and a dissolved lithium cation, de The surfactant component of the general formula below at least 0.010 ppt when no source of cabanadate anion and fluorine containing anion is supplied to the composition, In the above formula, x and y each represent a non-negative integer, R represents a hydrophobic group of a saturated alkyl component, the average value of the sum of x and y of all molecules in the surfactant component is 10 to 14, and The number of carbon atoms is 9.0-14.0. (D ") a source of at least 0.010 ppt of surfactant molecules conforming to the general formula below In the above formula, x and y each represent a non-negative integer, R represents a hydrophobic group of a saturated alkyl component, the average value of the sum of x and y of all molecules in the surfactant component is 10 to 14, and The number of carbon atoms is 9.0-14.0. A method of improving the corrosion resistance of a metal having a primary protective coating on the surface of the metal, the method comprising contacting the primary protective coating with the composition according to any one of claims 1 to 8. How to improve. 10. The method of claim 9, wherein the primary protective coating is formed by treating the cleaned metal surface with a primary treatment composition prepared by reacting the washed metal surface in an aqueous solution containing water and the dissolved components below. (A) cobalt (II) cations, (B) carboxylate anions, (C) Species which form more stable covalent bonds with cobalt (III) cations than cobalt (II) cations, except carboxylate anions, (D) oxidizing agents, In the above, the ratio of the number of moles of component (I) to the number of moles of component (A) in the aqueous solution before the reaction is 0.10 to 6.8. The method of claim 10, wherein the metal substrate is cleaned to deoxygenate the aluminum alloy, and the primary treatment composition is reacted among the dissolved components shown below. (A) Cobalt (II) cations having a concentration of about 0.60 to about 0.90 M (B) an acetate anion having a ratio of cobalt (II) cation concentration from about 2.3: 1.0 to about 3.4: 1.0, (C) hydroxyalkyl amines that impart a molar concentration of nitrogen atoms with unshared electron pairs to the primary treatment composition, wherein the ratio of molar concentrations of cobalt cations to from about 0.30: 1.0 to about 0.50: 1.0, (D) a peroxide component having a ratio of molar concentration of cobalt atoms from about 0.60: 1.0 to about 0.1: 1.0, and (E) nitrate ions having a ratio of cobalt ions to a molar concentration of about 1.0 to about 2.4, Optionally one or more of the following components (F) one component selected from the group consisting of cations of alkali metals and alkaline earth metals, and (G) fluoride anions and complex fluoride anions.