WATER VAPOR BARRIER COATING FOR COMPOSITE MATERIALS

• US 20080017069A1
• Filed: 10/04/2007
• Published: 01/24/2008
• Est. Priority Date: 01/28/2004
• Status: Abandoned Application

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Greszczuk, Longin
• Application Number:
  US11/867,564
• Publication Number:
  US 20080017069A1
• Time in Patent Office: Days
• US Class Current: 106/272
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C08L 2666/26 Natural polymers, natural resins or derivatives thereof according to C08L1/00 - C08L5/00, C08L89/00, C08L93/00, C08L97/00 or C08L99/00
• CPC Class Codes: C08L 91/06 Waxes
• CPC Class Codes: C08L 91/08 Mineral waxes
• CPC Class Codes: C09D 191/06 Waxes
• CPC Class Codes: C09D 191/08 Mineral waxes
• CPC Class Codes: C09D 5/1637 Macromolecular compounds
• CPC Class Codes: C09D 5/38 Paints containing free metal not provided for above in groups C09D5/00 - C09D5/36
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/69 Particle size larger than 1000 nm

Abstract

Embodiments provide composites (and core materials) that are coated with a water vapor barrier coating to reduce water vapor incursion into the composites (and core materials) and to reduce loss of residual moisture content from composite formed during the cure reaction. In an exemplary embodiment, coated composite articles have a composite substrate with a surface that has a water vapor barrier coating. The water vapor barrier-coating reduces water vapor incursion into the coated composite article through the surface when the coated composite is in a hot and humid surrounding environment by at least about 80%. The water vapor barrier coating includes a mixture of waxes and paraffins having a dispersion therein of inorganic powder comprising powdered metal, powdered metal oxide, or powdered metal carbide. The water vapor barrier coating is applied to the surface without solvents and is substantially free of pinhole gaps.

Claims

1. A coated composite article comprising:

a composite substrate comprising a resin matrix having a filler embedded therein, the composite substrate comprising a surface; and

a water vapor barrier coating the surface, the water vapor barrier-coating reducing water vapor incursion into the coated composite article through the surface when the coated composite is in a hot and humid surrounding environment by at least about 80% as compared to a like uncoated composite article in a like environment, the water vapor barrier coating comprising a mixture comprising waxes and paraffins having therein a dispersion of inorganic powder comprising powdered metal, powdered metal oxide, or powdered metal carbide throughout the mixture, the water vapor barrier coating applied to the surface without solvents and substantially free of pinhole gaps.

2. The coated composite of claim 1, wherein the coated composite article comprises:

graphite/phenolic nozzles of launch vehicles;

interstages and other primary structures of launch vehicles utilizing monocoque and sandwich construction;

composite structures of aircraft, marine structures made of composites, composite pressure vessels and numerous other applications utilizing composites, and in particular sandwich construction.

3. The coated composite of claim 2, wherein the paraffins comprise primarily aliphatic hydrocarbons having chain lengths in a range from about 18 to about 36 carbon atoms.

4. The coated composite of claim 1, wherein the inorganic powder comprises aluminum, titanium oxide or aluminum oxide.

5. The coated composite of claim 1, wherein the inorganic powder comprises aluminum powder in a size range from about 25 to about 60 microns.

6. The coated composite of claim 3, wherein the inorganic powder comprises aluminum powder in a size range from about 25 to about 60 microns.

7. The coated composite of claim 1, wherein the mixture is a solid at temperatures in a range below about 140°

F., and liquefies upon heating to a temperature in a range from about 170 to about 190°

F.

8. The coated composite of claim 1, wherein the mixture comprises an amount of inorganic powder in a range from about 5 wt. % to about 15 wt. %, based on weight of the mixture.

9. The coated composite of claim 1, wherein the water vapor barrier coating reduces water vapor absorption by from about 60 to about 100% as compared to a like uncoated composite.

10. A coated composite core material comprising:

a sandwich composite comprising a core material, the core material comprising a surface; and

a water vapor barrier coating the surface of the core, the water vapor barrier coating reducing water vapor incursion through the surface into the core material, when the coated composite is in a hot and humid surrounding environment, by at least about 80% as compared to a like uncoated composite core material in a like hot and humid environment, the water vapor barrier coating comprising a mixture comprising waxes and paraffins having dispersed therein an inorganic powder comprising powdered metal, powdered metal oxide, or powdered metal, the water vapor barrier coating applied without solvents and substantially free of pinhole gaps.

11. The coated composite core material of claim 10, wherein the paraffins comprise primarily aliphatic hydrocarbons having chain lengths in a range from about 18 to about 36 carbon atoms.

12. The coated composite core material of claim 10, wherein the core material comprises a cellular core material or a foam core material.

13. A barrier-coated composite, the barrier-coated composite comprising:

a composite substrate comprising a resin matrix having a filler embedded therein, the composite substrate comprising a surface to be exposed to a surrounding environment under ordinary conditions of use, the composite substrate comprising residual moisture produced by a resin cure reaction in formation of the composite substrate; and

a water vapor barrier coating on at least the surface exposed to the surrounding environment, the water vapor barrier-coating reducing loss of the residual moisture from the barrier-coated composite by at least about 80%, as compared to a like uncoated composite in a like surrounding environment, the water vapor barrier coating comprising a mixture comprising waxes and paraffins having a dispersion of an inorganic powder comprising powdered metal, metal oxide, or metal carbide throughout the mixture, the water vapor barrier coating applied to the surface without solvents and substantially free of pinhole gaps.

14. The barrier-coated composite of claim 13, wherein the mixture comprises beeswax and paraffins.

15. The barrier-coated composite of claim 13, wherein the paraffins comprise primarily aliphatic hydrocarbons having chain lengths in a range from about 18 to about 36 carbon atoms.

16. The barrier-coated composite of claim 13, wherein the inorganic powder comprises aluminum powder comprising particulates in a size range from about 25 to about 60 microns.

17. The barrier-coated composite of claim 13, wherein the inorganic powder comprises titanium oxide, aluminum oxide or aluminum.

18. The barrier-coated composite of claim 13, wherein the mixture is a solid at temperatures in a range below about 120°

F., and liquefies upon heating to a temperature in a range from about 140°

to about 180°

F.

19. The barrier-coated composite of claim 13, wherein residual moisture loss from the barrier coated composite is reduced by from about 60 to about 100% as compared to a residual moisture loss from a like uncoated composite.

20. The barrier-coated composite of claim 13, wherein the mixture is a solid at temperatures in a range below about 140°

F., and liquefies upon heating to a temperature in a range from about 170 to about 190°

F.