KR910006788B1 - Treatment of metal with derivative of polyalkenylphenol - Google Patents

Abstract

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Description

Method of treating metals with poly-alkenyl phenol derivatives

The present invention relates to metal surface treatment technology.

In particular, the present invention relates to the treatment of metal surfaces with acid salt solutions of poly-alkenylphenol derivatives or poly alkenylphenol derivatives. This treatment improves the corrosion resistance and paint adhesion to the metal surface.

It is known in the metalworking and other metal arts that it is necessary to apply a protective coating to the metal surface to improve corrosion resistance and paint adhesion. In the past, metal surfaces have been treated with chemicals that form metal phosphate and / or metal oxide conversion coatings on the metal surface to improve their corrosion resistance and paint adhesion. In addition, in the past, the conversion-coated metal surface has been cleaned or post-treated with a solution containing a hexavalent chromium compound to obtain greater corrosion resistance and paint adhesion.

However, due to the toxicity of hexavalent chromium compounds, expensive treatment equipment had to be used to remove chromate from plant wastewater to prevent contamination of rivers, streams or water sources. Therefore, although the corrosion resistance and paint adhesion of the conversion-coated metal surface can be improved by the post-treatment solution containing the hexavalent chromium compound, much research and efforts have been made in recent years to develop other effective methods instead of using the post-treatment solution. come. One alternative is given in US Pat. Appl. Ser. No. 210,910, filed Nov. 28, 1980, "Compositions and Methods for Post-treatment of Phosphated Metal Surfaces" (Andreas Lindert). As a workup compound in our previous application, it is used in workup solutions with alkaline pH. However, the aftertreatment compound is preferably useful in an aftertreatment solution of a wide pH range, particularly in an acidic aftertreatment solution.

According to the present invention, a novel composition is provided which is substituted for a hexavalent chromium compound-containing solution used as a post-treatment solution in a novel process for post-treatment of a phosphate treated or conversion coated metal surface. The present invention also provides solutions and methods for treating untreated metal surfaces, including aluminum, steel and zinc metal surfaces. The solution and method of the present invention provide a coating on the metal surface and are effective in improving the corrosion resistance and paint adhesion of the metal surface which is not previously converted or coated. The invention can be better understood from the following specification, where all parts and percentages are by weight unless otherwise indicated.

According to the present invention the metal surface is treated by contacting the metal surface with a solution containing an effective amount of a soluble or dispersible treatment compound selected from the group consisting of polymers having the general formula, acid salts, and mixtures thereof.

In the above formula,

R _1-3 is hydrogen or an alkyl group having from 1 to about 5 carbon atoms; Y is hydrogen, Z, CR ₄ R ₅ OR ₆ , CH ₂ Cl or a C _1-18 alkyl or aryl group;

R ₄ -R ₁₀ is hydrogen or alkyl, aryl, hydroxyalkyl, amino-alkyl, mercapto-alkyl or phospho-alkyl, wherein R ₄ -R ₁₀ is a length in which the carbon chain length is such that the compound is not dissolved or dispersed N is from 2 to the number at which a polymer is not dissolved or dispersed.

The invention also relates to a preferred treatment solution composed of the treatment compound in which the Z moiety is present. This solution is an aqueous solution and preferably the Z portion is present in an amount sufficient to make the compound water soluble or water dispersible.

The metal surface in contact with the solution composed of the above-mentioned treatment compound has improved corrosion resistance and paint adhesion. Although the solution of the present invention is effectively applied to treated or untreated metal surfaces, the best results are generally obtained when the metal surface is preconverted. Conversion coatings are known and are described, for example, in the following references: Metal Handbook, Vol II, 8th Edition, p 529-547, American Society for Metals and Metal Finishing Guidebook and Directory, p 590-603 (1972 ).

In metal processing operations using the compositions and methods of the present invention, the metal to be treated is first washed by chemical or physical methods and washed with water to remove oil and contamination from the surface. The metal surface is then brought into contact with the treatment solution of the present invention. In addition, instead of applying the treatment solution following the washing process, the conversion coating solution is applied to the metal surface in a conventional manner to form the conversion coating thereon. The coated surface is then washed with water and the metal surface immediately brought into contact with the treatment solution of the present invention.

The present invention relates to iron phosphate, manganese phosphate, zinc phosphate, or metals having a surface coated with a suitable conversion coating such as zinc phosphate modified with calcium, nickel or magnesium ions, mixed metal oxides and titanium or zirconium organometallic coatings. It is useful for a wide range of metal surfaces. Suitable metal surfaces include, for example, zinc, iron aluminum and cold rolled, ground, pickled, hot rolled steel and galvanized steel surfaces. The term "metal surface" herein includes both untreated metal surfaces and converted coated metal surfaces.

According to the method of the present invention, the metal surface is treated by contacting the metal surface with a solution containing the treatment solution of the present invention. The treating solution is composed of an effective amount of a soluble or dispersible treating compound selected from polymers having the general formula, acid salts thereof, and mixtures thereof:

In the above formula,

R _1-3 is hydrogen or an alkyl group having from 1 to about 5 carbon atoms; Each Y is hydrogen, Z, CR ₄ R ₅ OR ₆ , CH ₂ Cl or a C _1-18 alkyl or aryl group;

R ₄ -R ₁₀ is hydrogen or alkyl, aryl, hydroxy-alkyl, amino-alkyl, mercapto-alkyl or phospho-alkyl, wherein R ₄ -R ₁₀ has a carbon chain length such that the compound does not dissolve or disperse Up to length; n ranges from 2 to the number at which the polymer is not dissolved or dispersed.

It is preferable that Z part exists in a process solution. In addition, the treatment solution is an aqueous solution, it is preferable that the Z portion is present in an amount sufficient to make the compound water-soluble or water acidic.

The alkyl group of the polymer backbone or chain in the above structural formula may be in ortho, meta or para position relative to the hydroxyl group in the phenol aromatic ring, but the monomer units of the general formula are preferably selected from para and ortho forms.

The treated compounds of the present invention in the form of polymers may be composed of a number of different special monomer units, each having the above general formula. For example, the polymer compound of the present invention may have the following general formula;

Wherein Y is as defined above (except hydrogen), and A, B, C and D are from 0 up to the number at which the polymer does not dissolve or disperse in solvent under the conditions of use. A + B + C + D should be at least 2 and if the water is a solvent, the methyleneamine moiety, i.e. the Z moiety mentioned above, should be present in an amount sufficient to make the polymer water soluble or water dispersible when neutralized with acid. The mole percent, which is the amount necessary to be water soluble or water dispersible, depends on the molecular weight of the polymer as well as the particular R ₄ -R ₁₀ in the polymer. Usually the mole percentage of amino group or Z per phenol group varies from 10-200%, but usually 50-150%, which is one phenol group per monomer.

Of course, the treating compounds of the present invention are based on poly-alkenyl phenolic polymer derivatives. Poly-alkenyl phenols or substituted alkenylphenols useful in the present invention include, for example, isopropenylphenol, isobutenylphenol, dimethylvinylphenol and the like. Suitable derivatives having the above general formula can be prepared, for example, by the Mannich reaction. Poly-4-vinylphenol polymers, for example, are reacted with formaldehyde and secondary amines and then neutralized with organic or inorganic acids to yield products that can yield aqueous or water dispersible solutions or emulsions of the treatment compounds of the invention.

The molecular weight of the poly-alkenylphenols used in the preparation of the derivatives claimed in the present invention can range from dimers, or more generally low molecular weight oligomers up to 360 molecular weight, to 30,000 or more high molecular weight polymers. The upper limit of molecular weight is determined by the functional limits from which the derivative is dissolved or dispersed.

The aforementioned derivatives of the general formula usually have a molecular weight up to about 200,000 and within this range about 700-70,000 are preferred. The upper limit of "n" in the structural formula of these derivatives is usually about 850, with about 10-300 being preferred. Similarly, the carbon chain length of the R ₄ -R ₁₀ substituent is usually about 1-18, with about 1-12 being preferred. Of course, in each example the percentage of the "Z" moiety and the "n" value and carbon chain length are chosen such that the desired solubility and / or dispersibility is obtained.

The treating compound of the present invention is soluble in organic solvents and can be used as a treating solution when dissolved in an organic solvent such as ethanol. However, the treating compound may advantageously be used in aqueous solution. To obtain a water soluble or water dispersible compound, organic or inorganic acids can be used to neutralize the "Z" portion thereof. Acids useful for this purpose are acetic acid, citric acid, oxalic acid, ascorbic acid, phenylphosphonic acid, chloromethylphosphonic acid, mono, di and trichloroacetic acid, trifluoroacetic acid, nitric acid, phosphoric acid, hydrofluoric acid, sulfuric acid, boric acid, hydrochloric acid, Acids such as hexafluorosilicic acid, hexafluororutanic acid, hexafluorozirconic acid are used alone or in combination. The addition of water to the aforementioned neutralized, over-neutralized or partially neutralized treatment compounds yields water-soluble or water-dispersible solutions or emulsions of polymers useful for metal treatment.

The pH of the aqueous solution can vary from 0.5-12 but is usually maintained at 2.0-8.0 for practical purposes, i.e. for the stability of the solution and for best results on the treated metal surface.

The treating compounds of the present invention are used, for example, in working solutions of diluent concentrations of about 0.01-5% by weight. Practically a working solution of 0.025% -1% concentration is preferred. However, in some cases concentrated solutions may be desirable, for example when transporting or storing solutions. The treatment solution may also contain pigments, i.e. it may be a coating composition which may itself be a treatment compound and a paint composition containing a solvent and an inorganic or organic pigment.

Of course, the treatment solution of the present invention may also contain other components of the treatment compound. For example, the treatment solution may optionally contain about 0.001% -1.0% metal ions in addition to the treatment compound, which metal ion is selected from the group consisting of titanium, zirconium and hafnium ions and mixtures thereof. These ions are Group IVB transition metals of the Periodic Table of the Elements, such as their water-soluble acids or salts, such as hexafluorotitanic acid, hexafluorozirconic acid, hexafluorohafenic acid or nitrates, sulfates, fluorides, acetates, citrates and / or chloride salts. It can be made into an aqueous solution by addition of one. The use of these additional metal ions can improve both the efficacy and performance of the treatment solution used, and also for such short periods of time as the application of the treatment solution to the metal surface on the coil line, such as 2-5 seconds. Can be reduced.

In addition to or in lieu of the above-mentioned metal ions, other optional components may be used. For example, in addition to the treatment compound and the metal ion selected from the group consisting of titanium, zirconium and hafnium ions and mixtures thereof, the treatment solution may be a component selected from the group consisting of thiourea, alkyl or arylthiourea compounds, tannic acid, vegetable tannin or organzatannin and mixtures thereof. About 0.01-4.0%. Suitable ingredients include, for example, methyl, ethyl or butylthiourea, what was tantannin, manclovtanin or chestnut tannin, gestational tannin and valonea acorn cup extracts.

Applying the treatment solution of the present invention to the metal surface during the treatment process can be accomplished by any conventional method. The metal surface is preferably a conversion coated metal surface, but the treatment step can also be done on the untreated metal surface to increase its corrosion resistance and paint adhesion. For example, the treatment solution may be applied by spray coating, roller coating or dipping. The temperature of the solution used can vary widely, but 19-70 ° C. is preferred. After the treatment solution is applied to the metal surface, the surface may be arbitrarily cleaned, but good results may be obtained even after the treatment. However, it is also desirable to clean some applications, such as electrostatic painting.

The treated metal surface is then dried. Drying is carried out, for example, by circulating air or oven drying. Room temperature drying may be used, but high temperatures are preferred to reduce drying time.

After drying, the treated metal surface is ready for painting. The surface is suitable for standard paint or other coatings such as electrocoating and brush painting, spray painting, electrostatic painting, dipping, roller coating. As a result of the treatment step of the present invention, the conversion coated surface has improved paint adhesion and corrosion resistance. The invention will be better understood from the following examples.

Example 1

45 kg of 95% ethanol solvent was charged to an approximately 3791 stainless steel reactor equipped with a turbine blade, nitrogen spurs and cooler. After heating to 50 ° C., 36 kg of poly-4-vinylphenol polymer having a molecular weight of 5000 was slowly added to the solvent with good stirring. After all the polymer was added, the reactor was sealed and heated to 80 ° C. to help dissolve the remaining polymer. After the reactor was cooled to 40 ° C, 22.5 kg of N-methylaminoethanol and 45 kg of deionized water were added. 24.5 kg of 37% formaldehyde solution was added over 1 hour while maintaining the temperature at 40 ° C ± 2 ° C. Subsequently, the reactor was heated at 40 ° C. for 3 hours, 143 kg of 10% nitric acid was added, and then diluted with 10% solids using deionized water to obtain a stable aqueous solution of the treated compound of the present invention.

Example 2

100 g of cellosolve solvent was charged to a 1000 ml reaction flask reactor equipped with a chiller, a nitrogen sparger, a head phase stirrer and a thermometer. Then, 80 g of poly-4-vinylphenol having a molecular weight of 5000 was added to dissolve it. 70 g of diethanolamine and 100 g of deionized water were added, and the reaction solution was heated to 50 ° C. 108 g of 37% formaldehyde solution was added over 1 hour and then heated at 50 ° C. for 3 hours and then at 80 ° C. for 3 hours. After cooling the reaction solution, 65% of 75% phosphoric acid and 227g of deionized water were added. Thus, a stable aqueous solution of the treated compound of the present invention was obtained.

Example 3

To prevent corrosion during transportation, the oil-cold cold rolled steel 24 gauge panel is cleaned with mineral oil, followed by strong alkaline cleaner (trademark PARCO). Cleaner 338, Parker Surface Treatment Products, Occidental Chemical Corp. Products) After further washing by spraying for 60 seconds at a solution temperature of 66 ℃ using an aqueous solution, iron phosphate conversion coating (trade name BONDERITE 1041, Parker Surface Treatment Products, Occidental Chemical Corp.) was applied at 43 ℃ for 60 seconds. After the conversion coating treatment, the panel was washed with cold water for 30 seconds, and then sprayed for 30 seconds at 43 ° C. solution temperature with 0.5% solution of the compound of Example 1. Subsequently, the panel was washed and dried in an 177 ° C. oven for 5 minutes.

The panels were painted with standard Duracron 200 paint (PPG Industries) and examined by standard saline spraying (ASTM B-117-61). After 504 hours, the panel treated with the compound of Example 1 showed the same result as the standard chromium treated control panel.

Example 4

After adding 24.5 kg of 37% formaldehyde solution, the reaction was heated at 80 ° C. for 3 hours, and 148 kg of 10% phosphoric acid was added, followed by the procedure of Example 1, and the reactor contents were dehydrated with 10% solids. Dilution gave a stable aqueous solution of the treated compound of the present invention.

Example 5

The cold rolled steel panel was washed with a strong alkaline cleaner and the washed metal surface was washed with hot water. Iron phosphate coating (BONDERITE 1000, Parker Surface Treatment Products, Occidental Chemical Corp.) was sprayed at 71 ° C. and washed with cold water prior to post-treatment. The dilution solution of the poly-4-vinylphenol derivative prepared as in Example 4 was mixed with hexafluorotitanic acid and then applied to the metal phosphate at 49 ° C. The concentrations of poly-4-vinylphenol derivatives and hexafuluro titanic acid varied from 0.05-0.2% and 0.06-0.03%, respectively. Some of the post-treated panels were rinsed while others were not. All panels were then baked at 177 ° C. oven for 5 minutes. As a control panel, pacollene 60 chrome washed was used.

In order to obtain a coating thickness of 0.95-1.00mm and uniform coating appearance, the prepared panel was used for 60-90 seconds at 120-140 volts using a bipolar electrocoating system and a POWCRON 300 acrylic electrocoating agent (PPG Industry) at 24 ° C. Painted. The coating was cured for 20 minutes at 165 ° C. metal peak temperature. The panel was drawn using a sharp knife from X to corner until bare metal appeared. The panels were then subjected to a standard salt fog test according to ASTM B117-61 to compare with the deionized control as well as the chromate treated. Results equivalent to those of Parker Surface Treatment Products (Occidental Chemical Corp.) at 0.1% poly-4-vinylphenol derivatives containing 0.03% hexafluorotitanic acid in the treatment bath were obtained. lost.

Example 6

Cold rolled steel (CRS) panels were washed and treated to produce iron phosphate conversion coatings on the panels. The rough rolled steel (TRG) was washed and treated to produce a zinc phosphate conversion coating or a conversion coating in the form of a complex. Substrate samples prepared as mentioned above were finally cleaned for 10 seconds with one of the following final cleaners.

The panels were then painted with one or two-coat paint systems.

The panels were then drawn and subjected to the standard ASTM B-117-61 5% salt spray test, ASTM 2247-64T humidity test, and the 180 ° T-bend adhesion test described in ASTM D 3794-79. the results are as follow :

5% salt spray test result

The grade of red rust, degree of blister and creepback from scribe are reported above. The creep bag of the scribe resulting from the final detergent containing the polymer was substantially less than that from the deionized water final cleaner. When titanium was added, the creep bag from the scribe with the polymer cleaner had at least four out of six less than that of the chromic acid wash.

The humidity results of the cleaned iron phosphate coated panel were substantially equivalent. Adhesion in the 180 (* image) -band was at least equal to or better than chromic acid cleaning for polymer-containing cleaning.

Example 7

The panels were treated as in Example 6 except reducing the treatment time to 5 seconds. Excellent results were obtained for the zinc phosphate and metal complex conversion coatings compared to the chromic acid post-treatment, but the poly-4-vinylphenol derivative solution prepared as in Example 4 was prepared at a concentration of 0.1% with 0.02% hexafluoroacetic acid. Slightly weak results were obtained with iron phosphate when used at pH 5.1 of the treatment bath. Improved corrosion resistance was obtained by doubling the concentration in the treatment bath of poly-4-vinylphenol derivatives and hexafluorotitanic acid while incorporating 0.2% thiourea and 0.05% tannic acid into the formulation.

Example 8

The cleaned aluminum panel was treated with a BONDERITE 789 treatment agent (chromium-free Parker Surface Treatment Product, Occidental Chemical Corp conversion coating). After washing with cold water, one set of panels was washed with Pacolene 88 (a chromium-free Parker Surface Treatemnt Proatemnt Products, cleaner from Occidental Corp.) and the other set with a post-treatment agent as prepared in Example 4. .

After washing, the panel was passed through the compresses to remove excess solution. A chromium control was made using a Bondite 722 treatment and a final pacolen 10 cleaner (both from Parker Suface Products, Occidental Corp.). The panel was also passed through the squeezing bone after 10 washes of pacolene.

The treated panels were painted with two single coatings.

1.Hanna Paint-Hickory Brown Polyester XR8298D

2. DuPont Paint-White Acrylic 884-5001 Lusite 2100

The painted aluminum panel was subjected to acetate spray for 504 hours. After each 168 hours, the scribe side was graded by observing tape pull and paint damage, general blister and edge creping. After 504 hours the following results were observed.

E = Edge Class

S = Scribe Class

Salt spray test results assessed by creeping and blister resulting from scribe showed that the aluminum panel treated with Bonderite 787 treatment agent and post-treated with the poly-4-vinylphenol derivative of Example 4 was treated with Bonderite 722 treatment agent and pacolene 10. It was shown to be as good as or better than that treated with the control system.

Example 9

The panels were treated as in Example 5 except that each was rinsed for 5 seconds with one of the following solutions.

Panels were painted and tested as above. Cleaner No. The result of 2 is the cleaning agent No. which is a chromic acid control. Equal to or better than 1, except for the iron phosphate system, the results were good but slightly weaker than the chromic acid control. The result of detergent No. 3 was the same as or better than No. 2.

Although various embodiments of the present invention have been enumerated and described above, the present invention is not limited to the above-described compositions and methods, and the specific embodiments described herein as described in the examples are described in various modifications by those skilled in the art. Note that modifications are possible. Accordingly, the invention is limited only by the following claims.

Claims (18)

A method of treating a metal surface comprising contacting the metal surface with a solution composed of an effective amount of a soluble or dispersible compound selected from the group consisting of polymers of the following general formula, acid salts and mixtures thereof.

Wherein R _1-3 is hydrogen or a C _1-5 alkyl group; Y is hydrogen, Z, CR ₄ R | ₅ OR ₆ , CH ₂ Cl or C _1-10 alkyl or aryl group;

R ₄ -R ₁₀ is hydrogen or alkyl, aryl, hydroxy-alkyl, amino-alkyl, mercapto-alkyl or phospho-alkyl and R ₄ -R ₁₀ is a carbon chain having a compound dissolved or dispersed Not up to length; n is from 2 to the number at which the polymer is not dissolved or dispersed. The method of claim 1 wherein the solution is an aqueous solution and Z is present so that the mole percent of Z per monomer is 10-200%. The process of claim 2 wherein the mole percent of Z per monomer is 50-150%. The method of claim 2 wherein the pH of the solution is 2.0-8.0. The method of claim 1, wherein the compound is present in an amount of 0.025-1%. The compound of claim 4, wherein Z is

How to be. The compound of claim 4, wherein Z is

How to be. The method of claim 1 wherein said compound is a reaction product of poly-4-vinylphenol, formaldehyde and secondary amines. A metal surface treatment solution composed of an effective amount of a soluble or separable compound selected from the group consisting of polymers of the general formula, acid salts thereof and mixtures thereof.

Wherein R _1-3 is hydrogen or an alkyl group of C _1-5 ; Each Y is hydrogen, Z, CR ₄ R ₅ OR ₆ , CH ₂ Cl or C _1-18 alkyl or aryl group,

R ₄ -R ₁₀ is hydrogen, alkyl, aryl, hydroxy-alkyl, amino-alkyl, mercapto-alkyl or phospho-alkyl and R ₄ -R ₁₀ is a length of which the carbon chain length is not dissolved or dispersed Until; n is from 2 to the number at which the polymer is not dissolved or dispersed, where Z is present at 10-200% mole percent per mole monomer. The solution of claim 9 wherein the pigment is contained. The solution of claim 9 wherein said solution is paint. The solution of claim 9 wherein said solution is an aqueous solution. The solution of claim 9 wherein the mole percent of Z per monomer is 50-150%. The solution of claim 13 wherein the pH of the solution is 2.0-8.0. The solution of claim 9 wherein said compound is present in an amount of 0.025-1%. The compound of claim 9, wherein Z is

Phosphorus solution. The compound of claim 9, wherein Z is

Phosphorus solution. The solution of claim 9 wherein said compound is a reaction product of poly-4-vinylphenol, formaldehyde and secondary amines.