Multilayer erosion resistant protective films
Multilayer polymeric films which may be useful for protecting the leading edges of aircraft from rain and sand erosion are presented. Typical surface protection films comprising two or more layers of a first material alternating with one or more layers of a second material, wherein the first and second materials are different materials, wherein the first and second materials comprise first and second polymers, wherein the first and second materials have a first and second Shore hardness, and wherein the first Shore hardness is greater than the second Shore hardness by more than 5 A or more typically more than 10 A.
1. A surface protection film comprising five or more layers of a first material alternating with four or more layers of a second material, wherein the first and second materials are different materials, wherein the first and second materials comprise first and second polyurethane polymers, wherein the first and second materials have a first and second Shore hardness, and wherein the first Shore hardness is greater than the second Shore hardness by more than 5 A, wherein an outermost layer of the surface protection film is comprised of the first material.
2. The surface protection film of claim 1 wherein adjacent layers of first and second materials are in intimate contact.
3. The surface protection film of claim 1 wherein adjacent layers of first and second materials are linked by covalent bonds.
4. The surface protection film of claim 1 wherein adjacent layers of first and second materials are linked by covalent bonds of polymerization of the first and second polymers.
5. The surface protection film of claim 1 wherein the first and second materials comprise first and second fillers.
6. The surface protection film of claim 5 wherein the first and second fillers are different fillers.
7. The surface protection film of claim 5 wherein the first and second fillers are the same filler.
8. The surface protection film of claim 5 wherein the first and second polymers are the same polymer.
9. The surface protection film of claim 6 wherein the first and second polymers are the same polymer.
10. The surface protection film of claim 7 wherein the first and second polymers are the same polymer and wherein the first and second materials differ by amount of filler present.
11. The surface protection film of claim 1 wherein the first Shore hardness is greater than the second Shore hardness by more than 10 A.
12. The surface protection film of claim 1 wherein the first and second materials differ in hue or brightness.
13. The surface protection film of claim 1 comprising ten or more layers of the first material alternating with nine or more layers of the second material.
14. The surface protection film of claim 1 additionally comprising a layer of adhesive.
15. The surface protection film of claim 1 bound to an outer surface of an aircraft.
16. The surface protection film of claim 14 bound to an outer surface of an aircraft by the layer of adhesive.
17. A surface protection film comprising five or more layers of a first material alternating with four or more layers of a second material, wherein the first and second materials are different materials, wherein the first and second materials comprise first and second polymers, wherein the first and second materials have a first and second Shore hardness, wherein the first Shore hardness is greater than the second Shore hardness by more than 5 A, wherein the surface protection film is made by reactive co-extrusion of layers of the first and second materials and adjacent layers of first and second materials are linked by covalent bonds of polymerization of the first and second polymers, and wherein an outermost layer of the surface protection film is comprised of the first material.
18. The surface protection film of claim 17 wherein first and second polymers are different polymers belonging to a single class of polymers.
19. The surface protection film of claim 18 wherein the class of polymers is selected from the group of classes consisting of polyurethanes, polyureas, polyamides, polyesters, polyacrylates, silicones and polyolefins.
20. The surface protection film of claim 17 wherein the first and second materials comprise first and second fillers.
21. The surface protection film of claim 20 wherein the first and second fillers are different fillers.
22. The surface protection film of claim 20 wherein the first and second fillers are the same filler.
23. The surface protection film of claim 20 wherein the first and second polymers are the same polymer.
24. The surface protection film of claim 21 wherein the first and second polymers are the same polymer.
25. The surface protection film of claim 22 wherein the first and second polymers are the same polymer and wherein the first and second materials differ by amount of filler present.
26. The surface protection film of claim 17 wherein the first Shore hardness is greater than the second Shore hardness by more than 10 A.
27. The surface protection film of claim 17 wherein the first and second materials differ in hue or brightness.
28. The surface protection film of claim 17 comprising ten or more layers of the first material alternating with nine or more layers of the second material.
29. The surface protection film of claim 17 additionally comprising a layer of adhesive.
30. The surface protection film of claim 17 bound to an outer surface of an aircraft.
31. The surface protection film of claim 29 bound to an outer surface of an aircraft by the layer of adhesive.
32. A surface protection film comprising five or more layers of a first material alternating with four or more layers of a second material, wherein the first and second materials are different materials, wherein the first and second materials comprise first and second polymers, wherein the first and second materials have a first and second Shore hardness, and wherein the first Shore hardness is greater than the second Shore hardness by more than 5 A, and wherein the first Shore hardness is greater than or equal to about 90 A, wherein an outermost layer of the surface protection film is comprised of the first material.
33. The surface protection film of claim 32 wherein adjacent layers of first and second materials are in intimate contact.
34. The surface protection film of claim 32 wherein adjacent layers of first and second materials are linked by covalent bonds.
35. The surface protection film of claim 32 wherein adjacent layers of first and second materials are linked by covalent bonds of polymerization of the first and second polymers.
36. The surface protection film of claim 32 wherein first and second polymers are different polymers belonging to a single class of polymers.
37. The surface protection film of claim 36 wherein the class of polymers is selected from the group of classes consisting of polyurethanes, polyureas, polyamides, polyesters, polyacrylates, silicones and polyolefins.
38. The surface protection film of claim 32 wherein the first and second materials comprise first and second fillers.
39. The surface protection film of claim 38 wherein the first and second fillers are different fillers.
40. The surface protection film of claim 38 wherein the first and second fillers are the same filler.
41. The surface protection film of claim 38 wherein the first and second polymers are the same polymer.
42. The surface protection film of claim 39 wherein the first and second polymers are the same polymer.
43. The surface protection film of claim 40 wherein the first and second polymers are the same polymer and wherein the first and second materials differ by amount of filler present.
44. The surface protection film of claim 32 wherein the first Shore hardness is greater than the second Shore hardness by more than 10 A.
45. The surface protection film of claim 32 wherein the first and second materials differ in hue or brightness.
46. The surface protection film of claim 32 comprising ten or more layers of the first material alternating with nine or more layers of the second material.
47. The surface protection film of claim 32 additionally comprising a layer of adhesive.
48. The surface protection film of claim 32 bound to an outer surface of an aircraft.
49. The surface protection film of claim 47 bound to an outer surface of an aircraft by the layer of adhesive.
50. The surface protection film of claim 36 wherein first and second polymers are different polymers belonging to a single class of polymers.
51. The surface protection film of claim 50 wherein the class of polymers is selected from the group of classes consisting of polyurethanes, polyureas, polyamides, polyesters, polyacrylates, silicones and polyolefins.
52. The surface protection film of claim 1 wherein the first and second materials comprise first and second thermoplastic polyurethane polymers.
53. The surface protection film of claim 1 wherein the first Shore hardness is greater than the second Shore hardness by more than 20 A.
54. The surface protection film of claim 1 wherein the first Shore hardness is greater than the second Shore hardness by more than 25 A.
55. The surface protection film of claim 17 wherein the first Shore hardness is greater than the second Shore hardness by more than 20 A.
56. The surface protection film of claim 17 wherein the first Shore hardness is greater than the second Shore hardness by more than 25 A.
57. The surface protection film of claim 32 wherein the first Shore hardness is greater than the second Shore hardness by more than 20 A.
58. The surface protection film of claim 32 wherein the first Shore hardness is greater than the second Shore hardness by more than 25 A.