AIRCRAFT FLUID RESISTANT SEALANT FOR USE ON AIRCRAFT PARTS

Abstract

A number of sealants are provided that are resistant to degradation by aircraft fluids. In some embodiments, the sealants are resistant to degradation by Jet A fluid and at least one of the three types of hydraulic fluids typically used in aircraft. These embodiments are also typically cure in place from a two part polyurethane or polyurea mix, with cure to a visibly clear coating. In some embodiments, they may be sprayed on an aircraft surface or applied by hand (brush or injectable). In other of these embodiments, the sealants comprise, at least in part, a cured, soft, tacky polyurethane gel that is resistant to at least one of a synthetic hydrocarbon based or mineral oil based hydraulic fluid.

Claims

1. A method for sealing an aircraft surface, the method comprising: providing a two-part cartridge, the two-part cartridge having a first compartment and a second compartment, and a mixing straw in fluid communication with each compartment, wherein the first compartment contains a resin and the second compartment contains a hardener; providing a spray gun assembly dimensioned to accept the two-part cartridge and to, when triggered, apply pressure to the resin and hardener such that the resin and hardener mix in the mixing straw and are emitted from the mixing straw as an atomized spray of uncured mix; aiming, from a spaced apart position, the spray gun assembly at an aircraft surface and triggering the spray gun assembly such that the aircraft surface is struck with the atomized spray of uncured mix; and allowing the atomized spray to cure to form a visibly clear sealant coat on the aircraft surface, which visibly clear sealant is resistant to at least one of a phosphate ester based hydraulic fluid, a mineral oil-based hydraulic fluid or a synthetic hydrocarbon based hydraulic fluid and also resistant to Jet A fuel.

2. The method of claim 1, wherein the cure of the allowing step allows sealant coat to reach a hardness between 20 to 80 Shore A after 24 hours at about 77? F. (50% RH).

3. The method of claim 1, wherein the cured sealant coat of the allowing step is removable, tough and workable.

4. A sealant for use with a cartridge assembly, the cartridge assembly adapted to engage a spray gun, the spray gun for applying the sealant, the sealant comprising: a first polymer and a second polymer, the two polymers for curing upon being mixed and sprayed upon an aircraft surface, the curing forming a sealant coat that is aircraft fluid resistant.

5. The sealant of claim 4, wherein the sealant coat has a peel strength between 1 and 10 piw.

6. The sealant of claim 4, wherein the sealant coat has an elasticity of at least 125%.

7. The sealant of claim 4, wherein the sealant coat is visibly clear.

8. The sealant of claim 4, wherein the sealant coat cures rapidly.

9. The sealant of claim 4, wherein the sealant coat has a tensile strength of at least 100 psi.

10. A cartridge assembly for use with a spray gun, the spray gun for applying a sealant coating, the cartridge assembly comprising: a body having a first compartment and a second compartment, the first compartment containing a first component, the second compartment containing a second component, the body dimensioned to engage the spray gun, and a mixing straw engaged to the first and second compartments, the mixing straw configured to receive and when the cartridge assembly is engaged with the spray gun and the spray gun is energized, combine the first and second components to form an uncured sealant mix and emit the uncured sealant mix, under pressure, from a tip of the mixing straw at a removed end thereof to form a visibly clear, cured in place, sealant coat on an aircraft workpiece, the clear sealant coat being one of a polyurea, polyurethane or hybrid coat; wherein the cured sealant coat is resistant to at least one of a phosphate ester based hydraulic fluid, a mineral-based hydraulic fluid or a synthetic hydrocarbon based hydraulic fluid and also resistant to Jet A fuel.

11. The cartridge assembly of claim 10, wherein the sealant coat cures rapidly.

12. The cartridge assembly of claim 10, wherein the sealant coat has a hardness of between 20 and 80 Shore A.

13. The cartridge assembly of claim 10, wherein the sealant coat is removable, tough and workable.

14. A gasket for use as a sealant, the gasket comprising: a gasket body, the gasket body including a perimeter portion and a non-perimeter portion; and a skeleton, the skeleton at least partly encapsulated in the body, the skeleton having a perimeter portion and a non-perimeter portion; wherein the body is, at least in part, comprised of a cured polymer, the cured polymer being fluid resistant to a synthetic hydrocarbon based hydraulic fluid and also resistant to Jet A fuel.

15. The gasket of claim 14, wherein at least part of the body is soft and tacky.

16. The gasket of claim 15, wherein at least part of the body has a hardness of between 20 and 80 Shore A.

17. A tape for use as a sealant, the tape comprising: a carrier and a cured, non-adhesive polymer sealant some of which is in contact with the carrier and on an outer surface thereof, the cured, non-adhesive polymer sealant being fluid resistant to a synthetic hydrocarbon based hydraulic fluid and also resistant to Jet A fuel.

18. A gasket or gasket tape, the gasket or gasket tape comprising: a soft, tacky polymer gel body; and a carrier or skeleton at least partly saturated with the tacky polymer gel; wherein the gasket or gasket tape is Jet A fuel resistant and resistant to a synthetic hydrocarbon based hydraulic fluid.

19. The gasket or gasket tape of claim 18, wherein the gasket or gasket tape has a peel strength of between 1 and 5 piw.

20. The gasket or gasket tape of claim 18, wherein the gasket or gasket tape is a gasket tape and the carrier is at least partly open cell foam.

21. The gasket or gasket tape of claim 18, wherein the skeleton is fiberglass.

22. The gasket or gasket tape of claim 18, wherein the body comprises an outer surface of the gasket or gasket tape.

23. The gasket or gasket tape of claim 18, wherein the gasket or gasket tape has an elasticity of up to 400%.

24. The gasket or gasket tape of claim 18, wherein the gasket or gasket tape passes 12 second vertical burn.

25. The use on an aircraft of a two-part polyurethane or polyurea as a sealant, that when the two parts are mixed cures to form a visibly clear sealant coat on the aircraft, which visibly clear sealant coat is resistant to at least one of a phosphate ester based hydraulic fluid, a mineral oil based hydraulic fluid or a synthetic hydrocarbon based hydraulic fluid and also resistant to Jet A fuel.

26. The use according to claim 25, wherein the two parts of the polyurethane or polyurea comprise a resin and a harder.

27. The use according to claim 26, wherein the sealant is a sprayable sealant or a gasket.

28. The use according to claim 25, wherein the two parts of the polyurethane or polyurea are situated in a first compartment and a second compartment of a two-part cartridge, the two-part cartridge having a mixing straw in fluid communication with each compartment, wherein the first compartment contains a resin and the second compartment contains a hardener; the use of the two-part polyurethane further comprising, providing a spray gun assembly dimensioned to accept the two-part cartridge and to, when triggered, apply pressure to the resin and hardener such that the two mix in the mixing straw and are emitted from the mixing straw as an uncured mix, the spray gun assembly for emitting the uncured mix as an atomized spray; aiming from a spaced apart position the spray gun assembly at an aircraft surface and triggering the spray gun assembly such that the aircraft surface is struck with the atomized spray; and allowing the atomized spray to cure to form the visibly clear sealant coat on the aircraft, which visibly clear sealant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGS. 1 and 2 show a block of cured TS1228 aircraft fluid resistant sealant before testing as set forth herein.

[0024] FIGS. 1A and 1B show fluid spray test results for Jet A and Skydrol?, respectively.

[0025] FIGS. 2A and 2B show submersion test results for Jet A and Skydrol?, respectively, for the cured polyurethane aircraft fluid resistant sealant.

[0026] FIG. 3 is a perspective view cutaway of a gasket using at least in part Applicant's aircraft fluid resistant polymer as part of a body thereof.

[0027] FIG. 4 illustrates a view of a gasket in which Applicant's aircraft fluid resistant polymer is used, in a top view showing an inner and outer perimeter and fastener perimeters in a non-perimeter portion.

[0028] FIGS. 4A, 4B, 4C, 4D, 4E, and 4F illustrate various configurations of a gasket which uses Applicant's aircraft fluid resistant polyurethane sealant as all or a part thereof, in a straight cut (FIGS. 4A and 4B) overcut (FIG. 4C) undercut) (FIG. 4D) configuration, with FIGS. 4E and 4F showing an outer perimeter and gasket subject to compression between a workpiece and a base.

[0029] FIGS. 4G and 4H show the method of making and use of a fuel resistant perimeter encapsulating a mesh.

[0030] FIG. 5 shows an injection assembly having two compartments for use with Applicant's two component aircraft fluid resistant mix, illustrated making a cure in place wet seal.

[0031] FIG. 6 illustrates, when viewed in conjunction with FIG. 8, a cartridge assembly for use with a pneumatic spray gun for applying a two-part aircraft fluid resistant polyurethane coating to an aircraft part.

[0032] FIG. 7 illustrates one environment for use with Applicant's aircraft fluid resistant polyurethane sprayable coating; namely, an exterior surface of an aircraft fuel tank.

[0033] FIG. 8 illustrates a side view of a spray gun and cartridge assembly for applying Applicant's sprayable aircraft fluid resistant polyurethane coating to an aircraft part.

[0034] FIG. 9 illustrates a sealant for use with a backshell for connecting a cable to a connector.

[0035] FIGS. 9A-9E illustrate a fluid resistant backshell sealant and a method for encapsulating part or all of a space within a boot, the boot surrounding all or part of the backshell and some of the wires as well.

[0036] FIG. 10 illustrates a stretchable tape with aircraft fluid resistance for wrapping electrical connectors. FIGS. 10A, 10B, and 10C illustrate a stretchable aircraft fluid resistant tape used to wrap cable and cable connectors.

[0037] FIG. 11 illustrates a fluid resistant, clear sealant for use in seat tracks of aircraft. FIGS. 11A and 11B illustrate an aircraft fluid resistant sealant used as a filler in an aircraft seat track.

[0038] FIG. 12 illustrates an aircraft antenna having an aircraft fluid resistant coating on at least part of a leading edge thereof.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Applicant provides a two-part, polyurethane aircraft fluid resistant sealant, such as a gasket, tape, spray sealant, or injectable sealant, used at least in part, to make a sealant on aircraft parts. Applicant's sealant may be provided, in some embodiments, by use of TS1228 (available from KBS Chemical, Dodd City, Tex.) a two-part polyurethane that, when mixed, cures to form a watertight, tough, workable, durable elastomeric seal and may be used as all or part of a sealant on an aircraft part assembly, in some embodiments, a gasket, tape, injectable, or a sprayable sealant.

[0040] The TS1228 polyurethane sealant was tested in accordance with RTCA DO-160G Section 11, Fluids spray and submersion susceptibility to simulate accelerated real world application scenarios. All testing was performed at room temperature and only applicable fluids were tested (see Tables 1 and 2).

[0041] FIGS. 1 and 2 illustrate test specimens pre-immersion and pre-spray. FIG. 1A illustrates submersion results for a body comprised 100% of cured TS1228 after 168 hrs. in Jet A, visual inspection showing no change dimensionally and a 2% weight gain (see Table 1). Weight gain after 24 hours was 1%. The same material, TS1228 is illustrated in FIG. 1B after 168 hrs. of submersion in Skydrol LD-4, a phosphate ester based aircraft hydraulic fluid. An increase in weight of about 7% after 24 hours (19 percent after 168 hrs) in Skydrol LD-4 is observed. Both results are believed to be appreciably better than comparable products. (Table 1, for submersion test results and after 24 and 168 hrs. for a total of 16 different liquids, including Jet A, Skydrol? LD-4, and Mobil Aero HF.)

[0042] Submersion testing involves placing the sealant samples in a glass basin and completely submerging them in the fluid at room temperature and ambient air pressure. The samples are removed after 24 hrs. of exposure, air dry for 24 hrs., visually inspected, examined and weighed. They are then placed back in the fluid until a total of 168 hrs. of exposure is complete, then air dried, visually inspected, examined, and weighed.

[0043] TS1228 was also tested for aircraft fluid spray exposure and FIGS. 2A and 2B illustrate TS1228 after 24 hrs. of spray in Jet A fuel (FIG. 2A), Skydrol LD-4 (FIG. 2B). FIG. 2 shows the test assembly pre-testing. After 8/16/24 hours of spray, Jet A fuel showed the following weight change: 0.08%/0.06%/0.07%. Visible inspection and examination showed no physical deterioration. FIG. 2B shows Skydrol LD-4 after 24 hrs. The 8/16/24 hr. weight change is 65%/1.02%/1.66%, visible inspection and examination showing no physical deterioration. Table 2 attached shows seventeen fluids tested and results.

[0044] Applicants' SF2470 (KBS, Dodd City, Tex.) is a two-part polyurea cure in place sealant with workability, removability, toughness and durability. Where the dry to touch time of TS1228 is 15-30 min. at 77? F., SF2470 is 8-20 min. Dry through means a 6 pound thumb press and 90? turn at 77? F. does not leave a permanent impression. Dry through time for TS1228 is 3-6 hours and SF2470 is 1-2 hours.

[0045] Test SpecimensBoth Spray and Submersion

[0046] Material under testAv-DEC? TS1228 Injectable Sealant, as cured, measuring approximately 1.8?1.1?0.9 with an embedded wire

[0047] Test AssemblyBoth Spray and Submersion

[0048] A length of wire sufficient to hang specimen from rack was cut, measured and the mass was recorded. The material was injected into a Peel-A-Way disposable mold (R-40). The wire was embedded into the sealant. The specimens prepared for testing were allowed to cure for a period of 24 hours and then were removed from the mold. The mass of each test assembly was measured and recorded.

[0049] Applicants' cured sealants have a hardness (Shore A 50-60 in one range, Shore A 20 to 80 in another), elasticity (meaning elastomeric), moisture proof ability (observed and salt fog test), thermal range (?85? F. to 275? F.) and ability to withstand thermal and pressure cycling, either as a sprayable on the surface of an aircraft part, an injectable or on a gasket between facing surfaces under compression, or tape.

[0050] Applicant's sealant is also flame retardant under 14 CFR 25.853(a), Appendix F, Part 1(A)(1)(ii) (12 second vertical burn). It is amber, VOC-free, solvent-free, and visually clear in coating up to about ? to ?. Moreover, it is UV resistant, being exposed to over 5,000 hours of UV light without degradation.

[0051] Applicant's aircraft fluid resistant polymer sealant has a first part, resin which may have, at about 77? F. of viscosity between 70 to 250 cps, and a second part, such as a hardener, which may have at 77? F. viscosity of about 600 to 1200 cps. The gel time of a 10 gram mass at about 77? F. is less than about 15 mins. and it reaches full cure at about 8 to 24 hours. Thus, it may be termed fast curing. It has a working life after mixing of about ten minutes or less. It has a shelf life in original packaging and use within 24 hours after opening, of about nine months. It may, in some embodiments, have a peel strength of about 4.92 lbs. per inch width (4-6 in one range and 2-10 in another range), a tensile strength (ASTMD 412) of about 260 psi (or greater than 100 psi) and, in testing as an injectable, shows no corrosion present after 3000 hrs. salt fog (ASTMB 117). Peel strength is measured on a clean, dry surface of aluminum 6061/alloy with a cured ? thick layer, 90? peel slow, constant speed. When used as disclosed herein, it should retain its physical and chemical properties with no or minimal loss in functional properties.

[0052] FIG. 3 illustrates the use of Applicant's aircraft fluid resistant sealant in a gasket 10a with a body 12 and a skeleton 22. FIGS. 3 and 4 illustrate a gasket 10a/10b with body 12. Body 12 may include an outer perimeter 14 and an inner perimeter 16 (gasket 10b, FIG. 4), in some embodiments, fastener perimeters 20, as well as a non-perimeter portion 18. Gaskets 10a/10b may also include a skeleton 22, which has openings, and may be flat, and is typically encapsulated. All or part of body 12, including 14/16/18/20, may be made from any of Applicant's aircraft fluid resistant sealant. In some embodiments, non-perimeter portion 18 is a soft, tacky gel as described in U.S. Pat. No. 7,229,516, and one or more of 14/16/20 may be Applicant's fluid resistant polymers. In other embodiments, it is the soft, tacky aircraft fluid resistant gel as set forth below in FIG. 10.

[0053] Applicant's aircraft fluid resistant sealants TS1228, SF2470 or U1020/P1021 may be used to comprise any part or all of gasket body 12/14/16/18/20 and the rest of the body (if any) may be a polyurethane gel as set forth in U.S. Pat. Nos. 6,530,577 6,695,320; and 7,229,516, incorporated herein by reference. There may be no perimeter portions when the entire body is comprised of TS1228, for example.

[0054] Any gasket comprising at least in part body 12 may be made according to the methods described in the foregoing patents. When perimeter parts are made from Applicant's aircraft fluid resistant sealant, they may be made according to US Publication No. 2014/0167367, incorporated herein by reference.

[0055] FIG. 5 shows a use of the aircraft fluid resistant sealant being used as part of an injectable assembly 24, which includes two compartments 26/28, in some embodiments, one part for polyol and one part for isocyanate, the two parts being, in some embodiments, approximately a 2 to 1 volume ratio. The assembly is shown being used to apply a wet (uncured) seal around fastener holes 30. Injectable assembly 24 may have a forcing element 29 acting on the two separate compartments and forcing each to mix in through a mixing straw or nozzle 24a, from which they will emerge as a viscous liquid to cure in place on the gasket or aircraft part. A gasket made at least in part by Applicant's aircraft fluid resistant sealant may have either a fastener perimeter 20 cured in place during the manufacturing process of the gasket, or fastener holes or perimeters 30 may be left without a perimeter and may use a wet seal about the fastener holes when installed on an aircraft. The wet seal may include an uncured polyurethane TS1228 mix 32 injected when the gasket 10a/10b is placed on the workpiece and just before the fasteners are inserted through holes 30. The uncured mix cures to form a tough, aircraft fluid resistant polyurethane seal around the fastener and helps prevent corrosion while maintaining an environmental seal. More generally, TS1228 or SF2470 may be used as a cure-in-place injectable in any void or space on an aircraft where fluid resistance is needed and flame retardant is helpful also. In other embodiments, gaskets may be made with U1020/P1021 where tackiness and softness is needed along with fluid resistance.

[0056] FIGS. 4A, 4B, 4C, and 4D illustrate Applicant's at least partially fluid resistant gaskets 10a/10b used between a base and a workpiece, which base and workpiece typically have generally parallel surfaces and place the gasket, all or part, under compression therebetween. In these illustrations, the gasket is seen to have a non-perimeter portion 18 and an outer perimeter portion 14. (the gasket may also have a fastener perimeter 20 and/or an inner perimeter 16). In FIG. 4A, it is seen that the gasket may be die cut such that the outer perimeter of the gasket lies about even with the edge of the workpiece (the base is shown in FIG. 4F only). In this Figure, the skeleton 22 is a woven or mesh material, flexible. This is considered straight cut and compression will be applied to the entire gasket body, including the outer perimeter when fasteners or the like are used. FIG. 4B shows that a skeleton 22a may be a non-woven or non-mesh material like an impervious sheet. In FIG. 4C, it is seen that the gasket is made slightly larger (for example, about 2 mil to 750 mil or about 30 to 400 mil) so that the outer (or inner) perimeter extends beyond the edges of the workpiece in a pre-compressed state. FIG. 4C can be considered an overcut gasket. FIG. 4D is an undercut gasket where the gasket is cut slightly smaller (for example, about 2 mil to 750 mil or about 30 to 400 mil) at the outer perimeter than the outer perimeter of the workpiece. In FIG. 4E it is seen that a straight cut, under cut or overcut, may create an aircraft fuel resistant perimeter 14/16/20 (inner, outer or fastener), sealing completely around the workpiece WP, protecting a non-perimeter portion 18 that may or may not be a fluid resistant polymer or a tacky polyurethane gel. It is noted that the use of all perimeters 14/16/20 or some perimeters may provide for an entire gasket when under compression that is fluid resistant even when non-perimeter portion 18 may not be. That is, perimeters 14/16/20 may be configured such that, after compression, the only exposed portion of the gasket body is comprised of aircraft fluid resistant sealant.

[0057] FIGS. 4E and 4F show a perimeter portion 14, which may be an aircraft fluid resistant sealant, which does not physically encapsulate and cure around the skeleton 22/22a as seen, for example, in FIGS. 4A, 4B, 4C, and 4D, and in FIGS. 4G and 4H. FIGS. 4E and 4F show the body 12 undercut such that under compression as seen in FIG. 4F, the outer edge of 14 is about aligned with the outer edge of the workpiece or bulges out. In FIGS. 4E and 4F, the portion of the gasket body shown in the Figures may be added at or about the time (or anytime) the workpiece is connected to the base by using an injectable assembly 24 with a mixing nozzle 24a.

[0058] In FIGS. 4G and 4H, a perimeter 14/16/20 is provided to a gasket having a non-perimeter portion 18, which perimeter may be fluid resistant sealant and may be created by manufacturing a gasket with a portion of skeleton 22 extending beyond non-perimeter portion 18. In other words, a gasket with a skeletal perimeter initially sticking out beyond the body. Then, at the worksite when a gasket is placed between the workpiece and the base, a perimeter may be applied as illustrated in FIG. 4G with an uncured mix injected, poured or otherwise applied along the edge so it contacts and cures at least on that portion of the skeleton extending beyond the non-perimeter portion 18. Applicant's aircraft fluid resistant sealant cures fairly quickly, typically less than about 30 minutes and, in some cases, less than 15 minutes, and at the worksite (after applying the uncured mix and before it cures), one can use a tool straightedge or shaped tool to provide a straight cut as seen in FIG. 4H, solid line extending down from the perimeter of the workpiece to the base. Or, a shaped tool may be used to provide a fuel resistant perimeter with a shape that extends outward, shown by the dash line in FIG. 4H. It is to be noted that at least some of the embodiments of the gasket set forth herein may include a body being at least partially tacky, such as a body made at least in part by the tacky gel disclosed in U.S. Pat. No. 7,229,516, or U1020/P1021 (fluid resistant). Moreover, the aircraft fluid resistant body may have some tackiness, including for example, by applying to a surface thereof after cure, a thin veneer, such as about 1 to 10 mil, of the tacky gels disclosed in U.S. Pat. No. 7,229,516.

[0059] Although the gasket depicted in FIG. 4 as having a basic polygonal shape for sealing around a simple flange or against mating surfaces that surround an opening, it will be appreciated that the gasket is not limited to this or any other shape. Indeed, the gasket can be manufactured in a variety of shapes, sizes, and configurations. Woven fibers of the skeleton can be selected from a variety of fibers, including but not limited to, fiberglass fibers, carbon fibers, aramid fibers, cotton fibers, and polyester fibers. It is to be appreciated that other types of woven sheets having strands of threads in bundled fibers woven together in a variety of perpendicular and non-perpendicular, symmetrical or non-symmetrical patterns are possible.

[0060] FIGS. 5, 6, and 8 illustrate uses of Applicant's aircraft fluid resistant sealant as a two-part polymer sprayable (mix and spray simultaneously), which has, when cured, aircraft fluid resistant properties. The sealant is for spraying on aircraft parts to provide a tough, durable, workable and removable, sprayed on sealant coat. It has been found that a cartridge assembly 40 may be used for applying a two-part polymer sealant coating which results in a tough, visibly clear aircraft fluid resistant, sprayed on polymer sealant coat 42, the cartridge assembly with two parts used with a pneumatic mix and spray gun 44. Cartridge assembly 48 may have body 46 comprising a first compartment 48 and a second compartment 50. The first compartment may contain a first part of the two-part polyurethane or polyurea mix, for example, a polyol and the second compartment 50 may include a second part, such as an isocyanate. The polyol and isocyanate typically combine and mix in a nozzle 52 and are emitted as a spray. In one embodiment, a two part polyol to one part isocyanate ratio by volume is used. The spray may be sprayed on any aircraft workpiece, including the exterior and/or interior of hydraulic fittings, joints, surfaces, fuel fittings, tanks or surfaces, galleys, floors, cargo bays, and the like. Applicants' sealant may be applied to vertical aluminum alloy surfaces (sprayed on in some embodiments with Sulzer Mixpac MixCoat Spray Gun) in one embodiment, modified with compressed gas port on tip of nozzle 52 of the mixing straw to break up the mix into small particles. Typically HVLP dispensers or air spray guns will not be used, rather airless or air assisted spray equipment may be used. For more details regarding the use of a clear sprayable sealant and its optical properties (see '196 publication, incorporated herein by reference).

[0061] FIG. 7 illustrates two additional uses of applicants' sprayed on sealant coat 42. First, on the surface-outer or inner, of the fuselage of an aircraft. The second, as a secondary fuel barrier on aircraft fuel tanks such as the center wing box tank illustrated. Embodiments of a clear sprayable sealant for aircraft exteriors may have peel strengths of 25-30 piw and are flame retardant, per 12 second vertical burn.

[0062] Applicant's TS1228 or SF2470 sealant, whether used as an injectable, sprayable, gasket or tape, may be used in a thickness of about 3 to 60 mil in one range or about 10 to 50 mil in another range or up to ? in a third range and, in these ranges, and has sufficient clarity to see cracks (for example, when used as a sprayable) in the underlying aircraft part, while still being resistant to Jet A fuel and Skydrol as set forth herein.

[0063] Applicant's aircraft fluid resistant polyurethane sealant is VOC and solvent-free. It displays good cohesion, when sprayed on or applied in an uncured condition, to a metallic or non-metallic surface. It displays good cohesion to a knitted or woven mesh, metallic or non-metallic of a gasket when used as part of a gasket body. A gasket made at least in part of Applicant's aircraft fluid resistant sealant work well for corrosion resistance on an aircraft workpiece comprised of an aluminum alloy. Applicant's sealant, in an uncured but mixed condition, may have a viscosity typically between about 700 and 1200 cps, allowing it to be sprayed or injected and poured pursuant to methods found in U.S. Pat. No. 9,701,388, and the other documents incorporated herein by reference.

[0064] FIGS. 9-9E illustrate the use of two part, cure in place TS1228 in a cable and connector assembly 60. A method set forth herein describes the installation in an aircraft for use with injectable sealant TS1228 or SF2470, including fluid resistance and moisture protection to the connector. Cable and connector assemblies are used in a number of environments, including carrying electrical signals in aircraft. Cable and connector assemblies typically include a connector 62, which may be a plug (male) or a receptacle (female) connector, typically having multiple electronically conductive prongs or recesses (not shown), and a cable or a cable bundle 64 comprising multiple wires for connecting to multiple plugs or receptacles for transmitting electrical signals. Typically, a connector backshell 66 is used to help engage the cable or cable bundle to the connector. Connector backshell 66 has components specifically designed to be placed around that portion of a connector (plug or receptacle) which contains the facilities for attaching wires or cables. Backshell 66 is used to shield the wire connection points having interconnecting cable and a connector. Some backshells may include a cable clamp to secure the cable to the backshell and the connector. Backshells 66 may be used with any type of connector to protect the cable connections and to provide strain relief to the solder joints. Backshells may be straight, 45? or 90? as required by the design. Illustrated is a straight backshell 66, which includes a coupling ring 68 that may threadably couple the connector 62 to matching male or female connection (not shown). A molded boot 70 may be provided, such as an AvDEC feet shrink molded boot. Molded boots are available from many different sources and may be, as here, heat shrinkable to provide environmental protection to the coupling.

[0065] Following the method set below, it is seen in FIGS. 9C and 9E that boot 70, covering at least the upper part of the cable and connector assembly, may be at least partially filled with fluid resistant sealant 72, such as TS1228 or SF2470 as set forth herein, which will cure to provide a tough, hard, durable environmental sealant for providing resistance to fluids as set forth herein.

[0066] The surfaces should be cleaned with a clean cloth moistened with a cleaning solvent, such as isopropyl alcohol. Surfaces should be free of dirt, oil, grease, and other contamination prior to boot installation, including the cable, the connector, and the backshell.

[0067] The ends of molded boot 70 are labeled H (and lower) and J (upper). Slide the boot J end first over the electrical connector. Ensure that H end is facing the connector. Heat the H end of the boot with a hot air tool capable of producing sufficient heat to fully recover (shrink) the boot. The boot should be located and shrunken uniformly around the connector backshell, (leaving typically at least the lower part of the connector and the coupling ring uncovered) and only until it shrinks uniformly around the backshell. With the assembly held vertical, apply heat to the J end of the boot, moving up from H end. The molded boot may be removed by disconnecting the receptacle and plug and scoring the surface of the molded boot and concentrating the heat on the scored line. The boot should begin to separate along the line after which it can be peeled off. Injectable assembly 24 should be held firmly in place above the annulus around the cables or wires while forcing element 29 urges uncured mix 32 into the void. When cured, it will help create a moisture barrier between the regular surfaces and providing corrosion protection.

[0068] A sealant is provided for gasket, tape and injectable, where hardness is not needed but tackiness is, the sealant comprising soft gel in a tape, injectable or gasket, the gel with resistance to at least one of the three types of hydraulic fluid as well as Jet A fuel. In the form of a stretchable tape as illustrated in FIGS. 10, 10A-C, the tape may be to wrap cable connectors where they are in close proximity to hydraulic fluids. This two part polyurethane gel is available from KBS, Dodd City, Tex. U/1020/P1021 and when cured is tacky and soft, between 30-150 measured with a 35 gram half cone penetrometer. They may also be used in conjunction with injectables. See FIG. 10A.

[0069] FIG. 10 illustrates a stretchable, fluid resistant tape 80 that contains a cured mix 82 of U1020/P1021. This foam is at least partially or fully opened cell foam 84. It is resistant to hydraulic fluids, such as Aeroshell 31 (a synthetic hydrocarbon hydraulic fluid).

[0070] The gel, when subject to submersion in Aeroshell 31 showed the following results: 24 hours/1.7% weight gain; 48 hours/2.9% weight gain; 72 hours/3.9% weight gain; 5 days/5.2% weight gain; 10 days/5.4% weight gain; 20 days/5.5% weight gain; and, 32 days/5.5% weight gain. A weight gain of less than 10% for 24 hour immersion of the gel may be considered hydraulic fluid resistant, synthetic hydrocarbon.

[0071] Tape is typically provided in a roll and, as set forth herein, may provide some tackiness or stickiness to surface for optimal corrosion protection. It also passes 12 second vertical burn. It may be used with stringers, antennas, door shelves, access panels, windscreen installations, and other suitable locations.

[0072] FIGS. 11, 11A, and 11B illustrate a seat track sealant 90 for maintaining the position of a seat in an aircraft interior. Seat track sealant 90 may have an upper surface 90a. An injectable two-art sealant, such as TS1228, may be used in a seat track using injectable 24 to provide a cure in place seat tracker sealant 90 that provides a tough, durable, clear seal that keeps debris from entering the seat track, yet is removable, that is, has low adhesion to the walls of the seat track. In some embodiments, seat track sealant 90 may be filled to the level of top wall 90a. The injectable assembly 24 may be comprised of AvDEC Part No. SF2470, which, while it cures to amber, still retains sufficient clarity that cracks, debris or corrosion beneath the surface of the sealant may be readily identified (visually clear). This product is a two-component polyurea that cures to full cure in less than 4 hours and gels in 8 to 14 minutes. It has a peel strength of between 2 and about 10 piw, and passes salt fog 3000 hr. ASTMB 117, as well as 12 second vertical burn, 14 CFR Part 25 subpart d, Section 25.853, Compartment Interiors, and Section 25.855, Cargo or Baggage Compartments. The material will form a complete environmental seal, but is capable of being cleanly pull out of the track seat application in one piece, yet retains its tensile strength greater than 100 psi (ASTNB 412).

[0073] FIG. 12 illustrates an antenna sealant 96 for the exterior of an aircraft, in some cases, an antenna that depends below the fuselage of an aircraft behind at least some of the landing tires. Thus, the antenna may be subject to debris, such as rocks and pebbles, getting kicked up and striking the leading edge, especially when landing on unimproved runways. Applicant provides a two-component polyurethane material in some embodiments, spray or brush on TS1228 that cures smoothly and rigidly to the aircraft surface, including leading edge 96a, and at least part way to trailing edge 96b. Antenna sealant 98 being a two-component material that cures smoothly and rigidly to the surface of the antenna. It creates a watertight seal that can endure the toughest operational environments. Its rigid cure means increased abrasion resistance. It removes easily facilitating quick repair and inspections. In some embodiments, the hardness is in the Shore A range, for example, about 20 to 80, and it cures to full cure in less than 8 hours. The peel strength may be greater than 4 piw, in some embodiments, in the range of 4 to 10 piw. It passes the 12 second vertical burn test as set forth above and 3000 hours soft fog per ASTMB 117.

[0074] Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the invention.

TABLE-US-00001 TABLE 1 TS1228-Care Pre-Test 24 hours 168 Hours Facture Total Sample Change Total Sample Change Total Sample Sample Fluid Type Weight (g) Weight (g) Weight (g) (%) Weight (g) Weight (g) (%) Weight (g) Weight (g) Change (%) 1 Jet A Fuel 0.1129 23.9631 23.8502 0% 24.0871 23.9742 1% 24.3557 24.2428 2% 2 Autozone Brake Fluid 0.1041 22.5095 22.4054 0% 23.2124 23.1053 3% 24.3112 24.2071 8% 3 StycrolLD-4 0.1167 21.6004 21.4837 0% 23.0662 22.9495 7% 25.7519 25.6352 19% 4 AES Silicone Stoke 0.105 22.8783 22.7693 0% 12.994 22.885 1% 23.0107 22.9017 1% Fluid 5 Royco 752 0.1184 21.5808 21.5624 0% 21.8689 21.7505 1% 21.8248 21.7054 1% 6 White Mineral OS 0.1195 23.3362 23.2367 0% 23.4525 23.333 0% 23.4303 23.3108 0% 7 Royal Purple Sym 0.1156 21.6241 21.5063 0% 22.7459 21.6301 1% 21.737 21.6212 1% 8 Isopropyl 0.1196 21.3139 21.6343 0% 21.585 21.8654 1% 22.3207 22.2011 2% 9 Denatuced Ethyl 0.1263 22.4003 22.274 0% 22.7273 22.601 1% 23.4813 23.365 5% 10 Sky-Cleen 0.1184 23.1272 23.0088 0% 24.3259 24.2075 3% 26.6327 26.3143 13% 11 Dynalece EG 0.1168 22.5846 22.4678 0% 22.7036 22.5868 1% 22.6371 22.5203 0% 12 Dynalece PG 0.134 22.6515 22.5173 0% 22.7645 22.6305 1% 22.7245 22.5905 0% 13 Fluid PA 0.1219 21.1519 21.03 0% 21.2707 21.1488 1% 21.1833 21.0614 0% 14 Water 0.1198 22.2668 22.147 0% 22.2387 22.1189 0% 22.2398 22.12 0% 15 Mobil Aero HF 0.1264 22.235 22.1066 0% 22.3495 22.2231 1% 22.3943 22.2679 1% 16 5% NaCl Solution 0.1119 23.0594 22.5475 0% 23.0781 22.9652 0% 23.0756 22.5537 0% indicates data missing or illegible when filed

TABLE-US-00002 TABLE 2 % Weight % Weight % Weight Change Change Change Visual Test Fluid Class (8 hrs) (16 hrs) (24 hrs) Inspection Jet A Fuel Aviation Jet A Fuel 0.08% 0.06% 0.07% No change AutoZone Brake Non-Mineral Based 0.30% 0.47% 0.64% No change Fluid Hydraulic Fluid Skydrol LD-4 Phosphate Ester- 0.65% 1.02% 1.66% No change Based Hydraulic Fluid AGS Silicone Brake Silicone-Based 0.13% 0.12% 0.21% No change Fluid Hydraulic Fluid Royco 782 Synthetic 0.11% 0.12% 0.22% No change Hydrocarbon Based Hydraulic Fluid Mobil Aero HF Mineral-Based 0.16% 0.20% 0.17% No change Hydraulic Fluid White Mineral Oil Mineral-Based 0.23% 0.09% 0.18% No change Lubricating Oil Royal Purple Ester-Based 0.19% 0.15% 0.14% No change Synthetic Lubricating Oil Isopropyl Alcohol Isopropyl Alcohol 0.08% 0.06% 0.13% No change Solvent Denatured Ethyl Denature Alcohol 0.03% 0.03% 0.06% No change Solvent Sky-Kleen Solvent N/A 0.17% 0.24% 0.52% No change Dynalene EG Ethylene Glycol De- 0.24% 0.15% 0.18% No change Icing Fluid Dynalene PG Propylene Glycol 0.22% 0.15% 0.25% No change De-Icing Fluid De-Icing Fluid N/A 0.61% 1.05% 1.12% Salt Deposits Potassium Acetate on sample De-Icing Fluid N/A 0.34% 0.31% 0.18% No change Potassium Formate De-Ionized Natural Fluid 0.07% 0.04% 0.05% No change Water