Pretreatment compositions and methods of treating a substrate

Patent metadata

Field	Value
Publication number	US-10113070-B2
Application number	US-201514931913-A
Country	US
Kind code	B2
Filing date	Nov 4, 2015
Priority date	Nov 4, 2015
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

Disclosed is a pretreatment composition containing (a) a Group IIIB metal, a Group IVB metal, or combinations thereof; and (b) a compound containing at least six phosphorus-containing acid groups or salts thereof; wherein the molar ratio of (a) to (b) is at least 3:1. Also disclosed are methods of treating a substrate with the pretreatment composition and substrates treated with the pretreatment composition.

First claim

We claim:

1. A pretreatment composition for treating a metal substrate, comprising:
(a) a Group IIIB metal and/or a Group IVB metal present in a total amount of 20 ppm to 1000 ppm (calculated as elemental metal) based on the total weight of the pretreatment composition;
(b) a compound containing at least six phosphorus-containing acid groups or salts thereof present in an amount of 1.82×10 −4 moles per liter to 2.73×10 −2 moles per liter of pretreatment composition; and
(c) an electropositive metal;
wherein the molar ratio of (a) to (b) is at least 3:1;
wherein the pretreatment composition is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.

2. The pretreatment composition of claim 1 , wherein the Group IIIB and/or IVB metal comprise(s) zirconium, titanium, hafnium, yttrium, scandium, or a mixture thereof.

3. The pretreatment composition of claim 1 , wherein the compound containing at least six phosphorus-containing acid groups or salts thereof comprises phytic acid or salts thereof.

4. The pretreatment composition of claim 1 , wherein the electropositive metal is present in an amount of 2 ppm to 100 ppm based on the total weight of the pretreatment composition.

5. The pretreatment composition of claim 1 , further comprising a fluoride source present in an amount of 25 ppm to 500 ppm (calculated as total fluoride) based on the total weight of the pretreatment composition.

6. The pretreatment composition of claim 1 , further comprising an oxidizing agent present in an amount of 15 ppm to 300 ppm based on the total weight of the pretreatment composition.

7. The pretreatment composition of claim 1 , further comprising a fluoride source, an oxidizing agent comprising a metal source, or combinations thereof, wherein the molar ratio of Group TIM, Group IVB, and electropositive metals to the compound containing the at least six phosphorus-containing acid groups or salts thereof is greater than 1:1.

8. A pretreatment composition comprising:
(a) a Group IIIB and/or Group IVB metal;
(b) a compound containing at least six phosphorus-containing acid groups or salts thereof; and
(c) an electropositive metal;
wherein the molar ratio of (a) to (b) is at least 3:1;
wherein the pretreatment composition is substantially free of silicon;
wherein the pretreatment composition is substantially free of Group VB metals; and
wherein the pretreatment composition is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.

9. The pretreatment composition of claim 8 , wherein the Group IIIB and/or Group IVB metal comprises zirconium, titanium, hafnium, yttrium, scandium, or a mixture thereof.

10. The pretreatment composition of claim 8 , wherein the compound containing at least six phosphorus-containing acid groups or salts thereof comprises phytic acid or salts thereof.

11. The pretreatment composition of claim 8 , further comprising a fluoride source, an oxidizing agent, or combinations thereof.

12. A method for treating a metal substrate comprising:
contacting at least a portion of a surface of the substrate with a pretreatment composition comprising:
(a) a Group IIIB metal and/or a Group IVB metal in a total amount of 20 ppm to 1000 ppm (calculated as elemental metal) based on the total weight of the pretreatment composition;
(b) a compound containing at least six phosphorus-containing acid groups or salts thereof in an amount of 1.82×10 −4 moles per liter to 2.73×10 −2 moles per liter of pretreatment composition; and
(c) an electropositive metal;
wherein the molar ratio of (a) to (b) is at least 3:1; and
wherein the pretreatment composition is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.

13. The method of claim 12 , wherein the pretreatment composition further comprises a fluoride source, an oxidizing agent, or combinations thereof.

14. The method of claim 13 , further comprising contacting the surface with a pre-rinse composition prior to contacting at least a portion of the surface of the substrate with the pretreatment composition.

15. The method of claim 12 , further comprising contacting the surface that has been contacted with the pretreatment composition with a sealer composition.

16. The method of claim 15 , wherein the sealer composition comprises a Group IIIB metal, a Group IVB metal, a lanthanide, silica, aluminum, silane, organosilanes, phosphatized epoxies, or combinations thereof.

17. The method of claim 12 , further comprising depositing a coating composition comprising a film-forming resin onto at least a portion of the surface that has been contacted with the pretreatment composition.

18. The method of claim 15 , further comprising depositing a coating composition comprising a film-forming resin onto at least a portion of the surface that has been contacted with the sealer composition.

19. A treated metal substrate comprising:
a pretreatment layer formed on at least a portion of a surface of the substrate by contacting the portion of the surface of the substrate with a pretreatment composition comprising:
(a) a Group IIIB metal and/or a Group IVB metal in a total amount of 20 ppm to 1000 ppm (calculated as elemental metal) based on the total weight of the pretreatment composition;
(b) a compound containing at least six phosphorus-containing acid groups or salts thereof in an amount of 1.82×10 −4 moles per liter to 2.73×10 −2 moles per liter of pretreatment composition; and
(c) an electropositive metal;
wherein the molar ratio of (a) to (b) is at least 3:1; and
wherein the pretreatment composition is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.

20. The treated metal substrate of claim 19 , wherein the pretreatment composition further comprises a fluoride source, an oxidizing agent, or combinations thereof.

21. The treated metal substrate of claim 19 , further comprising a sealer layer comprising a Group IIIB metal, a Group IVB metal, a lanthanide, silica, aluminum, silane, organosilanes, phosphatized epoxies, or combinations thereof, wherein the sealer layer is formed on at least a portion of the pretreatment layer.

22. The treated substrate of claim 19 , further comprising a coating derived from a coating composition comprising a film-forming resin deposited over at least a portion of the layer formed by the pretreatment composition.

23. The treated substrate of claim 21 , further comprising a coating derived from a coating composition comprising a film-forming resin deposited over at least a portion of the layer formed by the sealer composition.

24. The pretreatment composition of claim 1 , wherein the pretreatment composition is substantially free of titanium metal.

25. The pretreatment composition of claim 8 , wherein the pretreatment composition is substantially free of titanium metal.

26. The method of claim 12 , wherein the pretreatment composition is substantially free of titanium metal.

27. The treated metal substrate of claim 19 , wherein the pretreatment composition is substantially free of titanium metal.

Assignees

• Ppg Ind Ohio Inc

Inventors

• Kolcun Adam
• Vargas Richard M
• Sylvester Kevin T
• Silvernail Nathan J
• Mcintyre John F

Classifications

• C23C22/34 Primary

  containing fluorides or complex fluorides · CPC title

• C23C22/36 Primary

  containing also phosphates · CPC title

• C23C22/83

  Chemical after-treatment · CPC title

• C09D5/10 Primary

  containing metal dust · CPC title

• C23C22/78

  Pretreatment of the material to be coated · CPC title