Method for producing scratch-resistant coatings

• US 6,777,458 B1
• Filed: 02/25/2002
• Issued: 08/17/2004
• Est. Priority Date: 08/25/1999
• Status: Expired due to Fees

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Kranwetvogel, Reiner, Schwalm, Reinhold, Jaworek, Thomas, Königer, Rainer
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): McClendon, Sanza L.
• Application Number:
  US10/049,646
• Time in Patent Office: 904 Days
• Field of Search: 522/1, 522/6, 522/90, 522/96, 522/100, 522/104, 522/107, 522/150, 522/152, 522/153, 522/157, 522/169, 522/170, 522/915, 522/12, 522/902, 522/120, 427/487, 427/491, 427/508, 427/510, 427/495, 264/494, 204/157.15, 204/157.44, 204/471, 204/478
• US Class Current: 522/1
• CPC Class Codes: B05D 3/0486 Operating the coating or treatment in a controlled atmosphere
• CPC Class Codes: B05D 3/067 Curing or cross-linking the coating
• CPC Class Codes: Y10S 522/902 Air inhibition

Abstract

A process for producing scratch-resistant coatings, encompassing the following steps:

applying at least one UV-curable coating composition to at least one surface of an article to be coated, said coating composition comprising at least one polymer and/or oligomer P1 containing on average at least one ethylenically unsaturated double bond per molecule, and

curing the coating composition by exposure to UV radiation,

which comprises conducting the curing of the coating composition under an oxygen-containing protective gas which has an oxygen partial pressure in the range from 0.2 to 18 kPa.

Claims

1. A process for producing a scratch-resistant coating, said process comprising:

applying at least one UV-curable coating composition to at least one surface of an article to be coated, said coating composition comprising at least one polymer and/or oligomer P1 containing an average of at least one ethylenically unsaturated double bond per molecule, and

curing said coating composition by exposure to UV radiation under an oxygen-containing protective gas which has an oxygen partial pressure in the range of from 0.5 to 18 kPa.

2. The process as claimed in claim 1, wherein the polymer and/or oligomer P1 has a double bond content in the range of from 0.01 to 1 mol/100 g of P1.

3. The process as claimed in claim 1, wherein a number-average molecular weight of P1 is in the range of from 400 to 10,000 daltons.

4. The process as claimed in claim 1, wherein the ethylenic double bonds in P1 are in the form of acrylate, methacrylate, acrylamido or methacrylamido groups.

5. The process as claimed in claim 4, wherein P1 is selected from the group consisting of urethane (meth)acrylates, polyester (meth)acrylates, oligoether (meth)acrylates and epoxy (meth)acrylates.

6. The process as claimed in claim 1, wherein the UV-curable coating composition further comprises one or more reactive diluents.

7. The process as claimed in claim 6, wherein the reactive diluent is selected from the group consisting of compounds having one or two acrylate groups, compounds having one or two methacrylate groups and mixtures thereof.

8. The process as claimed in claim 1, wherein the article to be coated is a three-dimensional structure.

9. The process as claimed in claim 1, wherein a region of an installation in which the coating is cured by exposure to UV radiation is flushed with a protective gas.

10. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 0.5 to 17 kPa.

11. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 0.5 to 15.3 kPa.

12. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 0.5 to 13.5 kPa.

13. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 0.5 to 10 kPa.

14. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 0.5 to 6.3 kPa.

15. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 0.9 to 6.3 kPa.

16. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 1.8 to 6.3 kPa.

17. The process as claimed in claim 1, wherein the oxygen partial pressure is in the range of from 2.5 to 6.3 kPa.