Self-healing coating system

• US 7,723,405 B2
• Filed: 01/05/2007
• Issued: 05/25/2010
• Est. Priority Date: 01/05/2006
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Cho, Soo Hyoun, White, Scott R., Braun, Paul V.
• Primary Examiner(s): Gulakowski; Randy
• Assistant Examiner(s): NELSON, LINDSAY ANN
• Application Number:
  US11/620,276
• Publication Number:
  US 20070166542A1
• Time in Patent Office: 1,236 Days
• Field of Search: 523/212
• US Class Current: 523/212
• CPC Class Codes: B29C 73/163 Sealing compositions or agents, e.g. combined with propellant agents
• CPC Class Codes: B29C 73/22 the article containing elements including a sealing composition, e.g. powder being liberated when the article is damaged
• CPC Class Codes: C08G 77/04 Polysiloxanes
• CPC Class Codes: C08G 77/60 in which all the silicon atoms are connected by linkages other than oxygen atoms
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08K 9/10 Encapsulated ingredients
• CPC Class Codes: C08L 101/00 Compositions of unspecified macromolecular compounds
• CPC Class Codes: C08L 2666/28 Non-macromolecular organic substances
• CPC Class Codes: C08L 2666/52 Metal-containing compounds
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: C09D 5/00 Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced electrically insulating plastics, resins or waxes H01B3/30; Filling pastes
• CPC Class Codes: C09D 7/65 macromolecular C09D7/41-C09D7/48 take precedence
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: C09D 7/68 Particle size between 100-1000 nm
• CPC Class Codes: C09D 7/69 Particle size larger than 1000 nm
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: Y10T 428/2985 Solid-walled microcapsule from synthetic polymer

Abstract

A self-healing coating includes a polymer matrix, a polymerizer, and a set of capsules containing a corresponding activator for the polymerizer. The polymerizer may be present in another set of capsules, or the polymerizer may be phase separated from the polymer matrix. The coating may be prepared by depositing a coating composition on a substrate and solidifying the coating composition, where the coating composition includes the polymerizer, the activator capsules and a matrix precursor. A combination of polymerizer capsules and activator capsules may be part of a kit, which may be used to provide self-healing properties to a coating. The polymerizer and the activator may be wet-curable, and coatings containing the polymerizer and activator may be able to self-heal when in contact with water.

Claims

1. A composition, comprising:

a plurality of first capsules comprising a siloxane polymerizer;

a plurality of second capsules comprising a corresponding activator for the siloxane polymerizer; and

a polymer matrix;

where, when the composition is configured as a coating on a metal substrate and the coating is scribed to the substrate, heated at 50°

C. for 24 hours and placed in a 5 wt % aqueous sodium chloride solution for 120 hours, there is no visible corrosion at the metal below the scribed section.

2. The composition of claim 1, where the polymerizer comprises a polymerizer for poly(dimethyl siloxane).

3. The composition of claim 2, where the polymerizer comprises a mixture of hydroxyl terminated polydimethylsiloxane and polydiethoxysiloxane.

4. The composition of claim 1, where the corresponding activator comprises a catalyst selected from the group consisting of amines and metal salts.

5. The composition of claim 1, where the corresponding activator comprises a metal salt of a carboxylic acid.

6. The composition of claim 1, where the corresponding activator comprises a tin salt.

7. The composition of claim 6, where the tin salt is a salt of a carboxylic acid.

9. The composition of claim 1, where the siloxane polymerizer is a liquid.

10. The composition of claim 1, where the siloxane polymerizer and the corresponding activator are wet-curable.

11. The composition of claim 1, where the siloxane polymerizer and the corresponding activator, when contacted, can form a polysiloxane at room temperature.

12. The composition of claim 1, where the polymer matrix comprises an epoxy vinyl ester polymer.

13. The composition of claim 1, where the polymer matrix comprises an epoxy polymer.

14. The composition of claim 1, where the composition further comprises an adhesion promoter.

20. The composition of claim 2, where

the corresponding activator comprises a metal salt,

the siloxane polymerizer is a liquid,

the siloxane polymerizer and the corresponding activator are wet-curable and, when contacted, can form a polysiloxane at room temperature.

8. A method of making a coating, comprising:

contacting a composition with a metal substrate;

the composition comprising a plurality of first capsules comprising a siloxane polymerizer,

a plurality of second capsules comprising a corresponding activator for the siloxane polymerizer, and

a matrix precursor, and

solidifying the matrix precursor to form a coating on the substrate;

where when the coating is scribed to the substrate, heated at 50°

C. for 24 hours and placed in a 5 wt % aqueous sodium chloride solution for 120 hours, there is no visible corrosion at the metal below the scribed section.

15. The method of claim 8, where the polymerizer comprises a mixture of hydroxyl terminated polydimethylsiloxane and polydiethoxysiloxane.

16. The method of claim 8, where the corresponding activator comprises a catalyst selected from the group consisting of amines and metal salts.

17. The method of claim 8, where the composition further comprises an adhesion promoter.

18. The method of claim 8, where the matrix precursor comprises a precursor for an epoxy vinyl ester polymer.

19. The method of claim 8, where the matrix precursor comprises a precursor for an epoxy polymer.