Metal pretreatment composition containing zirconium, copper, zinc and nitrate and related coatings on metal substrates

Patent metadata

Field	Value
Publication number	US-2018237918-A1
Application number	US-201815961262-A
Country	US
Kind code	A1
Filing date	Apr 24, 2018
Priority date	Dec 28, 2009
Publication date	Aug 23, 2018
Grant date	—

Abstract

A pretreatment composition for metal that provides enhanced corrosion resistance, enhanced paint adhesion and reduced chip damage to a wide variety of metal substrates. The pretreatment is also cleaner because it is based on zirconium rather than zinc phosphates. The pretreatment coating composition in use preferably comprises 50 to 300 parts per million (ppm) zirconium, 0 to 100 ppm of SiO2, 150-2000 ppm of total fluorine and 10-100 ppm of free fluorine, 150 to 10000 ppm of zinc and 10 to 10000 ppm of an oxidizing agent and has a pH of 3.0 to 5.0, preferably about 4.0. The coating composition can optionally include 0 to 50 ppm of copper. The suitable oxidizing agents can be selected from a large group.

First claim

What is claimed is:

1 . A metal pretreatment coating composition comprising the following components: 50 to 300 ppm of zirconium; 0 to 50 ppm of copper; 0 to 100 ppm of SiO 2 ; 150 to 2000 ppm total fluorine; 10 to 100 ppm free fluorine; 600 to 10000 ppm zinc; and 10 to 10,000 ppm of an oxidizing agent; and having an acidic pH; wherein at least one oxidizing agent is an ion or salt of nitrate, present in an amount of from 600 to 10,000 ppm and said components are selected such that the coating composition is capable of depositing an amount of zirconium that is less than an otherwise identical coating composition that is devoid of zinc under the same process conditions.

2 . The metal pretreatment coating composition according to claim 1 comprising 75 to 300 ppm of zirconium, 10 to 40 ppm of copper and 20 to 100 ppm of SiO 2 .

3 . The metal pretreatment coating composition according to claim 1 wherein said oxidizing agent comprises at least one of a nitrate ion or salt, a nitrite ion or salt, an inorganic peroxide, a permanganate ion or salt, a persulfate ion or salt, a perborate ion or salt, a chlorate ion or salt, a hypochlorite ion or salt, a vanadate ion or salt, a vanadyl ion or salt, a ceric ion or salt, a tungstate ion or salt, a stannic ion or salt, a hydroxylamine, a nitro-compound, an amine oxide, hydrogen peroxide, or a mixture thereof.

4 . The metal pretreatment coating composition according to claim 3 wherein said oxidizing agent comprises at least one of ammonium nitrate, sodium nitrate, potassium nitrate, sodium nitrite, sodium peroxide, potassium permanganate, sodium persulfate, sodium perborate, sodium chlorate, sodium hypochlorite, sodium vanadate, vanadyl sulfate, ceric sulfate, ceric ammonium sulfate, ceric ammonium nitrate, sodium tungstate, stannic fluoride, hydroxylamine, hydroxylamine sulfate, sodium nitrobenzene sulfonate, sodium m-nitrobenzene sulfonate, and N-methylmorpholine N-oxide.

5 . The metal pretreatment coating composition according to claim 1 having a pH of about 3.0 to about 5.0.

6 . The metal pretreatment coating composition according to claim 1 wherein said oxidizing agent comprises hydrogen peroxide present in an amount of from 10 to 30 ppm and has a pH of about 3.5 to about 4.5.

7 . A pretreatment coated metal substrate comprising: a pretreatment coating on a metal substrate wherein said pretreatment coating is derived from a pretreatment coating composition according to claim 1 .

8 . The pretreatment coated metal substrate according to claim 7 wherein said pretreatment coating is derived from a pretreatment coating composition further comprising: 75 to 300 ppm of zirconium, 0 to 40 ppm of copper and 20 to 100 ppm of SiO 2 .

9 . The pretreatment coated metal substrate according to claim 7 wherein said oxidizing agent comprises at least one of a nitrate ion or salt, a nitrite ion or salt, an inorganic peroxide, a permanganate ion or salt, a persulfate ion or salt, a perborate ion or salt, a chlorate ion or salt, a hypochlorite ion or salt, a vanadate ion or salt, a vanadyl ion or salt, a ceric ion or salt, a tungstate ion or salt, a stannic ion or salt, a hydroxylamine, a nitro-compound, an amine oxide, hydrogen peroxide, or a mixture thereof.

10 . The pretreatment coated metal substrate according to claim 7 wherein said oxidizing agent comprises an ion or salt of nitrate or sulfate present in an amount of from 600 to 10000 ppm.

11 . The pretreatment coated metal substrate according to claim 7 wherein said oxidizing agent comprises hydrogen peroxide present in an amount of from 10 to 30 ppm.

12 . The pretreatment coated metal substrate according to claim 7 wherein said metal substrate comprises metals selected from the group consisting of cold rolled steel (CRS), hot-rolled steel, stainless steel, steel coated with zinc metal, a zinc alloy, electrogalvanized steel (EG), galvalume, galvanneal, hot-dipped galvanized steel (HDG), an aluminum alloy and an aluminum and combinations thereof.

13 . A component comprising the pretreatment coated metal substrate according to claim 12 wherein the metal substrate comprises a combination of at least two of said metals.

14 . The metal pretreatment coated metal substrate according to claim 7 further comprising an electrocoating layer having a thickness of from 0.7 to 1.2 mils on top of said pretreatment coating.

15 . A coated metal substrate comprising a zirconium based conversion coating layer deposited on a metal substrate comprising cold rolled steel, said zirconium based conversion coating layer comprising Zr, Fe, Cu and Zn.

16 . The coated metal substrate according to claim 16 wherein the Zr is present in an amount of 20 atomic % or less and the Zn is present in an amount of at least 0.5 atomic %.

17 . The coated metal substrate according to claim 16 wherein the zirconium based conversion coating layer has a coating weight of 18 to 83 mg/m 2 , measured as Zr.

18 . The metal pretreatment coated metal substrate according to claim 17 further comprising an electrocoating layer having a thickness of from 0.7 to 1.2 mils on top of said pretreatment coating.

19 . The metal pretreatment coated metal substrate according to claim 17 further comprising a topcoat layer on top of said electrocoating layer.

Assignees

• Henkel Ag & Co Kgaa

Inventors

• Vonk Donald
• Kapic Edis
• Goodreau Bruce
• Bobadilla Alvaro

Classifications

• Y10T428/12139

  Nonmetal particles in particulate component · CPC title

• C23C22/34 Primary

  containing fluorides or complex fluorides · CPC title

• C23C22/06

  using aqueous acidic solutions with pH less than 6 · CPC title

• C23C22/80 Primary

  with solutions containing titanium or zirconium compounds · CPC title

• C23C22/78

  Pretreatment of the material to be coated · CPC title