THERMAL ACOUSTIC INSULATION BLANKETS

Abstract

The present invention pertains to an insulation system comprising one or more insulation blankets, wherein each of said multilayer insulation blankets comprises: a core consisting of an insulation material [material (I)], and a shell encapsulating said core, said shell comprising at least one multilayer assembly comprising: (1) an outer layer [layer (L1)] consisting of a composition [composition (C1)] comprising, preferably consisting of at least one thermoplastic polymer [polymer (1)] having a limiting oxygen index (LOI) of at least 20% by volume, wherein at least one surface, preferably the inner surface, of said layer (L1) comprises one or more grafted functional groups [surface (L1-f)], (2) directly adhered to said at least one surface (L1-f), a layer consisting of at least one metal compound (M1) [layer (L2)], and (3) optionally, directly adhered to the opposite side of the layer (L2), a layer consisting of at least one metal compound (M2) [layer (L3)], said metal compound (M2) being equal to or different from said metal compound (M1). The present invention also pertains to a process for the manufacture of said insulation system and to uses of said insulation system in various applications including aircraft applications.

Claims

1. A process for the manufacture of an insulation system comprising one or more insulation blankets, said process comprising: encapsulating a core consisting of an insulation material (I) with a shell comprising a multilayer assembly, said multilayer assembly being obtainable by: treating at least one surface of a layer (L1) by a radio-frequency glow discharge process in the presence of an etching gas medium, wherein layer (L1) consists of a composition (C1) comprising at least one thermoplastic polymer (1) having a limiting oxygen index (LOI) of at least 20% by volume, applying by electroless deposition a layer (L2) onto said at least one treated surface of layer (L1), wherein layer (L2) consists of at least one metal compound (M1), and optionally, applying by electro-deposition a layer (L3) onto the opposite side of layer (L2) wherein layer (L3) consists of at least one metal compound (M2), said metal compound (M2) being equal to or different from said metal compound (M1).

2. The process according to claim 1, wherein layer (L1) is the outer layer of the shell.

3. The process according to claim 1, wherein polymer (1) is selected from the group consisting of: a fluoropolymer (F) having a limiting oxygen index (LOI) of at least 30% by volume, and a poly(aryl ether ketone) having a limiting oxygen index (LOI) of at least 30% by volume.

4. The process according to claim 3, wherein fluoropolymer (F) is selected from the group consisting of: polymers comprising recurring units derived from at least one fluorinated monomer selected from tetrafluoroethylene (TFE) and chlorotrifluoroethylene (CTFE), and from at least one hydrogenated monomer selected from ethylene, propylene and isobutylene, optionally containing one or more additional comonomers; polymers comprising recurring units derived from vinylidene fluoride (VDF), and, optionally, from one or more fluorinated monomers different from VDF; polymers comprising recurring units derived from tetrafluoroethylene (TFE) and at least one fluorinated monomer different from TFE selected from the group consisting of: perfluoroalkylvinylethers of formula CF.sub.2CFOR.sub.f1 wherein R.sub.f1 is a C.sub.1-C.sub.6 perfluoroalkyl group; perfluoro-oxyalkylvinylethers of formula CF.sub.2CFOX.sub.0 wherein X.sub.0 is a C.sub.1-C.sub.12 perfluorooxyalkyl group comprising one or more ether groups; C.sub.3-C.sub.8 perfluoroolefins; and perfluorodioxoles of formula (I): ##STR00007## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4, equal to or different from each other, are independently selected from the group consisting of F, a C.sub.1-C.sub.6 fluoroalkyl group, optionally comprising one or more oxygen atoms, and a C.sub.1-C.sub.6 fluoroalkoxy group, optionally comprising one or more oxygen atoms; and polymers comprising recurring units derived from at least one cyclopolymerizable monomer of formula CR.sub.7R.sub.8CR.sub.9OCR.sub.10R.sub.11(CR.sub.12R.sub.13).sub.a(O).sub.bCR.sub.14CR.sub.15R.sub.16, wherein each R.sub.7 to R.sub.16, independently of one another, is selected from F and a C.sub.1-C.sub.3 fluoroalkyl group, a is 0 or 1, b is 0 or 1 with the proviso that b is 0 when a is 1.

5. The process according to claim 1, wherein the etching gas medium is selected from the group consisting of air, N.sub.2, NH.sub.3, CH.sub.4, CO.sub.2, He, O.sub.2, H.sub.2 and mixtures thereof.

6. The process according to claim 5, wherein the etching gas medium comprises N.sub.2 and/or NH.sub.3 and, optionally, H.sub.2.

7. The process according to claim 1, wherein metal compound (M1) is selected from the group consisting of Rh, Ir, Ru, Ti, Re, Os, Cd, Tl, Pb, Bi, In, Sb, Al, Ti, Cu, Ni, Pd, V, Fe, Cr, Mn, Co, Zn, Mo, W, Ag, Au, Pt, Ir, Ru, Pd, Sn, Ge, Ga, alloys thereof and derivatives thereof.

8. The process according to claim 1, wherein layer (L3) is applied onto the opposite side of the layer (L2) by electro-deposition.

9. The process according to claim 8, wherein metal compound (M2) is selected from the group consisting of Rh, Ir, Ru, Ti, Re, Os, Cd, Tl, Pb, Bi, In, Sb, Al, Ti, Cu, Ni, Pd, V, Fe, Cr, Mn, Co, Zn, Mo, W, Ag, Au, Pt, Ir, Ru, Pd, Sn, Ge, Ga, alloys thereof and derivatives thereof.

10. An insulation system comprising one or more multilayer insulation blankets, wherein each of said multilayer insulation blankets comprises: a core consisting of an insulation material (I), and a shell encapsulating said core, said shell comprising at least one multilayer assembly comprising: (1) an outer layer (L1) consisting of a composition (C1) comprising at least one thermoplastic polymer (1) having a limiting oxygen index (LOI) of at least 20% by volume, wherein at least one surface (L1-f) of said layer (L1) comprises one or more grafted functional groups, (2) directly adhered to said at least one surface (L1-f), a layer (L2) consisting of at least one metal compound (M1), and (3) optionally, directly adhered to the opposite side of the layer (L2), a layer (L3) consisting of at least one metal compound (M2), said metal compound (M2) being equal to or different from said metal compound (M1).

11. The insulation system according to claim 10, wherein the one or more grafted functional groups are selected from the group consisting of amine groups (NH.sub.2), imine groups (CHNH), nitrile groups (CN) and amide groups (CONH.sub.2).

12. The insulation system according to claim 10, wherein layer (L2) has a thickness between 0.05 m and 5 m.

13. The insulation system according to claim 10, wherein layer (L3), if any, has a thickness between 0.1 m and 30 m.

14. An aircraft insulation system comprising the insulation system according to claim 10.

15. The process according to claim 1, wherein composition (C1) consists of at least one thermoplastic polymer (1) having a limiting oxygen index (LOI) of at least 20% by volume.

16. The insulation system according to claim 10, wherein composition (C1) consists of at least one thermoplastic polymer (1) having a limiting oxygen index (LOI) of at least 20% by volume.

17. The insulation system according to claim 12, wherein layer (L2) has a thickness between 0.8 m and 1.5 m.

18. The insulation system according to claim 13, wherein layer (L3), if any, has a thickness between 1 m and 15 m.

Description

EXAMPLE 1

Manufacture of an Insulation System

[0197] 1-AManufacture of PEEK-1 Layer

[0198] The PEEK-1 layer was manufactured by processing PEEK-1 pellets in a coextrusion cast film line equipped with a 2.5 single stage extruder. The extruder was connected to a flat auto-gauge die. Upon exit from the die, a molten tape was casted on three subsequent chill rolls, whose speed was adapted so as to obtain the desired film thickness. Total thickness and thickness variation along the width were controlled by a Beta-ray gauge control system with retrofit to the die.

1-BSurface Modification

[0199] The PEEK-1 layer obtained according to Example 1-A was treated at atmospheric pressure by a radio-frequency plasma discharge process. The etching gas was a mixture of N.sub.2 (95% by volume) and H.sub.2 (5% by volume). The working frequency was 40 kHz and the voltage was 20 kV. It has been found by XPS analysis that the so treated surface of the PEEK-1 layer comprises functional groups containing nitrogen groups (2.87 At %).

1-CMetallization Process

[0200] The PEEK-1 layer obtained according to Example 1-B was coated with metallic copper by electroless plating. Prior to copper deposition, the PEEK-1 layer so treated was activated by immersion in an aqueous solution containing 0.03 g/L of PdCl.sub.2 for 1 minute, resulting in the treated PEEK-1 layer being entirely coated with Pd particles at a high density. The activated PEEK-1 layer was then immersed in an aqueous plating bath containing 10 g/L of CuSO.sub.4 and 0.01 g/L of formaldehyde. The plating temperature was 25 C. and its pH value was 4.

COMPARATIVE EXAMPLE 1

[0201] The PEEK-1 layer obtained according to Example 1-A was provided as such. As confirmed by XPS analysis, the surface of the PEEK-1 layer does not contain functional groups containing nitrogen groups.

[0202] It has been found that the metallized polymer (1) layers of the insulation system according to the invention advantageously provide for lower water vapour permeability as compared with untreated polymer (1) layers (see Table 1 here below).

TABLE-US-00001 TABLE 1 WVTR Run [perms U.S.] Ex. 1 0.1 C. Ex. 1 0.2

[0203] The insulation system according to the invention is thus particularly suitable for use in aircraft applications.