Rinsable metal pretreatment methods and compositions

a pretreatment method and metal technology, applied in the direction of metal material coating process, coating, solid-state diffusion coating, etc., can solve the problem of significant disposal of solid sludge from such waste treatment procedures, and achieve the effect of improving corrosion protection

US20060151070A1Inactive Publication Date: 2006-07-13CHEMETALL CORP
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
Publication Date
2006-07-13
Estimated Expiration
Not applicable · inactive patent

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Abstract

Chromate-free and metal phosphate free treatments and compositions for applying a conversion or passivation coating for metals, more particularly, steel, zinc coated steel, and aluminum surfaces. The methods of the invention comprise contacting the requisite metal surface with a treatment composition comprising a member or members comprising one or more Group IV B elements, fluoride, and phosphonic acid or phosphonate. Optionally, a silane may be added as a treatment component.
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Description

FIELD OF INVENTION

[0001] The present invention relates to non-chrome containing coatings for metals. More particularly, the present invention relates to rinsable, non-chromate, non-metal phosphate coatings for steel, zinc coated steel, and aluminum surfaces to improve the adhesion of siccative coatings to the surface and provide enhanced corrosion protection. BACKGROUND OF THE INVENTION

[0002] It is well known to those skilled in the art to employ a chromate or phosphate conversion or passivation coating on the surface of metals to impart improved corrosion resistance of bare and painted metal, improve adhesion of coatings, and for aesthetic purposes. For example, see Corrosion, L. L. Sheir, R. A. Jarman, G. T. Burstein, Eds. (3rd Edition, Butterworth-Heinemann Ltd, Oxford, 1994), Volume 2, chapter 15.3.

[0003] Growing concerns exist regarding the toxicity profile of chromium and the pollution effect of chromates, phosphates and other heavy metals discharged into rivers and waterwa...

Examples

example 1

[0047] The following formulations were evaluated to examine the effect of phosphonate addition to the base titanium+zirconium formulation Panels were processed and painted as in Comparative Example 1. Test results are contained in

TABLE 2Grams / LiterA-1A-2A-3A-4A-5A-6A-7Ti(ioPr)40.120.120.120.120.120.120.12H2ZrF61.51.51.51.51.51.51.5EBO0.250.250.250.25BBPA0.50.31.0CEPA0.300.51.0THSPMP0.5WaterRemainderRemainderRemainderRemainderRemainderRemainderRemainderGrams / LiterA-8A-9A-10C-1 (comparative)Ti(ioPr)40.120.120.12TEOS5.0H2ZrF61.51.51.5GPTMS7.5EBO0.25UPTMS7.5BBPAEDPA0.5CEPAWaterRemainderTHSPMP0.5TBBPA0.30.5WaterRemainderRemainderRemainder

Abbrevations used:

Ti(ioPr)4 = Titanium Isopropoxide

EBO = mixed linear and cyclic EBOs

Linear EBO = Phosphonic acid [[2-hydroxyethyl)imino] bis (mythylene)] bis-, N-oxide

Cyclic EBO = Phosphonic acid [(tetrahydro-2-hydroxy-4H-1,4,2-oxazaphosphorin-4-yl)methyl]-N, P-dioxide

BBPA = 4-bromobenzylphosphonic acid

CEPA = 2-carboxyethylphosphonic acid

TEOS =...

example 2

[0049] The following additional formulations were prepared and painted as in Comparative Example 1.

Grams / LiterX-1X-2X-3X-4X-5X-6X-7Ti(ioPr)40.120.240.120.240.120.240.12H2ZrF6 (45%)1.53.01.53.01.53.01.5EBO0.250.250.250.512.53BBPA0.070.3PPA0.1310.701.41.0WaterRemainderRemainderRemainderRemainderRemainderRemainderRemainderGrams / LiterX-8X-9X-10X-11X-12X-14X-15Ti(ioPr)40.240.120.240.120.230.120.24H2ZrF6 (45%)3.01.53.01.52.91.53.0EBO5.0BBPA0.070.130.62TBBPA2.17WaterRemainderRemainderRemainderRemainderRemainderRemainderRemainder

Abbrevations used:

Same as in Example 2, additionally PPA = phenylphosphonic acid.

[0050] Neutral Spray Salt Tests in accordance with ASTM B-117 and D-1654 were conducted as reported in Example 1. Results are reported in Table 3.

TABLE 3Average MeanCreepage -millimeters.Formulation168 hours336 hoursX-11.23.0X-22.66.3X-33.37.5X-45.010X-50.92.6X-61.12.1X-73.18.75X-84.910.0X-91.42.7X-101.73.8X-113.38.7X-1210.0NAX-141.03.9X-151.53.1

example 3

[0051] Additional phosphonates were evaluated as in Example 1. A base formulation of Ti and Zr components was prepared as follows:

[0052] Base Formulation:

ComponentsGrams / LTi(iOPr)40.12H2ZrF6 (45%)1.5 WaterRemaining

[0053] Neutral salt spray results are reported in Table 4.

TABLE 4Phosphonate168 hours336 hoursLevelNSS (mmNSS (mmPhosphonate(grams / L)creep)creep)2-Carboxyethylphosphonic Acid0.50.72.84-Bromobenzylphosphonic Acid0.50.31.24-tertbutylbenzenephosphonic Acid0.51.72.33-Trhihydroxysilylpropylmethyl-phosphonate0.50.81.44-hydroxybenzylphosphonic acid0.250.71.04-nitrobenzylphosphonic acid0.251.11.44-methylbenzylphosphonic acid0.251.31.54-Bromobenzyl phosphonate ester0.250.91.4Bromophenyltrimethoxysilane0.50.81.4Iminobis(methylphosphonic acid)0.11.02.7tert-butylphosphonic Acid0.10.71.5EBO phosphonate0.25*1.5 + / − 0.4*2.5 + / − 0.6*Zinc phosphate / chrome sealedB958 / P600.911.85*Zinc phosphate / non-chrome sealedB958 / P950.951.93

Note

NSS results are averages of 2 panels.

*Average of 20 pa...