Two-component systems for producing flexible coatings

• US 7,927,704 B2
• Filed: 09/20/2006
• Issued: 04/19/2011
• Est. Priority Date: 10/04/2005
• Status: Active Grant

• Current Assignee: Covestro Deutschland AG
• Original Assignee: Bayer Materialscience AG (Covestro AG)
• Inventors: Niesten, Meike, Mager, Michael, Homann, Malte
• Primary Examiner(s): Tran; Thao T.
• Application Number:
  US11/524,001
• Publication Number:
  US 20070078255A1
• Time in Patent Office: 1,672 Days
• Field of Search: 428/423.1, 528/59, 528/60, 528/61
• US Class Current: 428/423.1
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/3821 Carboxylic acids; Esters thereof with monohydroxyl compounds
• CPC Class Codes: C08G 18/4854 Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
• CPC Class Codes: C08G 18/4866 having a low unsaturation value
• CPC Class Codes: C08G 18/7837 containing allophanate groups
• CPC Class Codes: C09D 175/12 from compounds containing nitrogen and active hydrogen, the nitrogen atom not being part of an isocyanate group
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]

Abstract

The present invention relates to two-component coating systems for producing flexible coatings. The coating systems comprise polyurethane prepolymers with allophanate structures and also amino-functional polyaspartic esters as curing agents.

Claims

1. A two-component coating composition comprising

A) a polyisocyanate prepolymer having polyether groups attached via allophanate groups and

B) an amino-functional polyaspartic ester of formula I)

2. The two-component coating composition of claim 1, wherein A1) and A3) said aliphatic and/or cycloaliphatic polyisocyanates used to prepare the allophanate modified polyisocyanate prepolymer A) comprises hexane diisocyanate (hexamethylene diisocyanate, HDI), 4,4′

-methylenebis(cyclohexyl isocyanate) and/or 3,5,5-trimethyl-1-isocyanato-3-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI).

3. The two-component coating composition of claim 1, in which component A1) and component A3) comprise the same polyisocyanate.

4. The two-component coating composition of claim 1, wherein A4) said catalyst comprises one or more zinc(II) compounds.

5. The two-component coating composition of claim 4, wherein said zinc(II) compounds comprise zinc(II) bis(2-ethylhexanoate), zinc(II) bis(n-octoate), zinc(II) bis(stearate) or mixtures thereof.

6. The two-component coating composition of claim 1, wherein A2) comprises exclusively one or more polyether polyols having number average molecular weights M_n of 2000 to 6000 g/mol, an average OH functionality of ≦

1.95 and a degree of unsaturated end groups of less than or equal to 0.01 meq/g.

7. The two-component coating composition of claim 1, wherein the equivalent ratio of the OH groups of the compounds of component A2) to the NCO-groups of the polyisocyanates from A1) and A3) is from 1:

2 to 1;

10.

8. The two-component coating composition of claim 1, wherein A5) said stabilizers comprise organic or inorganic acids, acid halides or esters.

9. A coating obtained from the coating composition of claim 1.

10. A substrate that has been coated with the composition of claim 1.