U.S. patent application number 15/799022 was filed with the patent office on 2018-03-08 for non-adhesive thin gel sealants and methods of making and using the same.
The applicant listed for this patent is THE PATENT WELL LLC. Invention is credited to Kent Boomer, Matt Boyd, Jeff Busby, Mike Dry, Chad Knight, David Schmidt, Peter Sibello.
Application Number | 20180066693 15/799022 |
Document ID | / |
Family ID | 54367438 |
Filed Date | 2018-03-08 |
United States Patent
Application |
20180066693 |
Kind Code |
A1 |
Busby; Jeff ; et
al. |
March 8, 2018 |
NON-ADHESIVE THIN GEL SEALANTS AND METHODS OF MAKING AND USING THE
SAME
Abstract
Applicant provides a number of embodiments of a sealant, the
sealant comprising a polyurethane gel which, in some embodiments,
has a thickness of 12 mil or less (uncompressed). Uses of the
sealant are shown, including uses between aircraft parts under
compression. Sometimes the sealant may have a very thin skeleton.
Sometimes the sealant is in the form of a die cut gasket, a tape or
a tacky gel sprayable. Methods for making the sealant are also
disclosed. The sealants may be used pre-cured or may be sprayed on
to the aircraft parts and form in place.
Inventors: |
Busby; Jeff; (Millsap,
TX) ; Schmidt; David; (Egg Harbor Township, NJ)
; Boomer; Kent; (Alvedo, TX) ; Boyd; Matt;
(Fort Worth, TX) ; Dry; Mike; (Fort Worth, TX)
; Knight; Chad; (Dodd City, TX) ; Sibello;
Peter; (Benbrook, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE PATENT WELL LLC |
Fort Worth |
TX |
US |
|
|
Family ID: |
54367438 |
Appl. No.: |
15/799022 |
Filed: |
October 31, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14704030 |
May 5, 2015 |
9803674 |
|
|
15799022 |
|
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61988949 |
May 6, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 15/095 20130101;
B32B 2581/00 20130101; B64C 1/00 20130101; Y10T 29/49959 20150115;
C09J 5/00 20130101; C09J 2301/50 20200801; B64C 1/12 20130101; F16J
15/14 20130101; C09J 7/403 20180101; F16B 5/04 20130101; C09J 7/40
20180101; F16B 19/00 20130101; F16B 19/008 20130101; B32B 15/016
20130101; B32B 15/20 20130101; F16B 19/04 20130101 |
International
Class: |
F16B 19/00 20060101
F16B019/00; B32B 15/095 20060101 B32B015/095; B32B 15/20 20060101
B32B015/20; B64C 1/00 20060101 B64C001/00; B64C 1/12 20060101
B64C001/12; C09J 5/00 20060101 C09J005/00; C09J 7/02 20060101
C09J007/02; F16B 19/04 20060101 F16B019/04; F16J 15/14 20060101
F16J015/14; B32B 15/01 20060101 B32B015/01 |
Claims
1. A device for use on an aircraft assembly, the aircraft assembly
having a first part having an inner face portion; a second part
having an inner face portion; and a multiplicity of fasteners for
joining the two parts, the device comprising: a sealant for
placement between the two inner face portions, the sealant
comprising a tacky, deformable body of polyurethane gel, the body
with tacky outer faces wherein the body has a thickness of 12 mil
or less uncompressed; further comprising a skeleton configured with
many openings, the skeleton encapsulated in the body and the
skeleton having an uncompressed thickness of 12 mil or less.
2. The device of claim 1, wherein the body has a thickness of
between about 1-6 mil when compressed between the two parts.
3. The device of claim 1, wherein the polyurethane gel is
cured.
4. The device of claim 1, wherein the assembly is a lap joint, a
double, a patch, a heat shield or include electronic equipment.
5. The device of claim 1, wherein the tacky body is deposited on
one or both of the first or second part by a pneumatic spray
gel.
6. The device of claim 1, wherein the body is pre-cured before
placement on one of the two inner face portions.
7. The device of claim 1, wherein the body cures after placement on
one of the two inner face portions.
8. The device of claim 1, further comprising a release film.
9. The device of claim 1, wherein the skeleton is a woven mesh.
10. The device of claim 1, wherein the skeleton is metallic.
11. The device of claim 1, wherein the skeleton is
non-metallic.
12. The device of claim 1, wherein the skeleton is molded or
extruded polyamide or polypropylene.
13. An aircraft having a fuselage, the fuselage comprising:
multiple panels which overlap partially, the overlaps comprising
multiple lap joints; wherein the lap joints comprise facing
surfaces, the facing surfaces having a thin, tacky, cured,
deformable, resilient polyurethane gasket for compression
therebetween.
14. The fuselage of claim 13, wherein the compressed gasket
thickness is less than about 6 mil.
15. The fuselage of claim 13, wherein the gasket includes a
skeleton.
16. A method of joining two adjacent parts on an aircraft, the
method comprising the steps of: obtaining a thin gasket assembly
comprising a cured polyurethane gel body gasket or tape having a
first, tacky side and a second tacky side, the gasket assembly
comprising a release film on one of the sides; applying the first
side to an inner face of one of the two parts; positioning an inner
face of the other of the two parts adjacent the gasket or tape;
removing the release film from the second side of the gasket before
the following step; and, joining the parts with fasteners.
17. A method of manufacturing a thin gasket having a tacky
polyurethane gel body, the method comprising the steps of:
providing a release film that has been to easily release from a
cured tacky polyurethane gel body; applying an uncured mix of the
gel to the adapted release film to a thickness of about 12 mil or
less; and allowing the uncured mix to cure.
18. The method of claim 17, wherein the release film of the
providing step has multiple perforations therethrough.
19. The method of claim 17, wherein the release film of the
providing step is at least partly coated with release agent.
20. The method of claim 17, wherein the release film of the
providing step is meltable.
21. A sealant for use with an aircraft having a first part and a
second part connected with fasteners, the sealant consisting
essentially of: a sealant for receipt between the parts of the
aircraft, the sealant comprising a resilient, cured, deformable,
polyurethane body having a tacky polyurethane upper surface and a
tacky polyurethane lower surface; and at least one release film for
placement against at least one of the upper or lower surfaces of
the body, the release film for removal from the body before
placement of the sealant on an aircraft part.
22. The sealant of claim 21, wherein the body has an uncompressed
thickness of less than 12 mil.
23. The sealant of claim 21, wherein the body has an uncompressed
thickness of between 2 and 12 mil.
24. The sealant of claim 21, wherein the body has a compressed
thickness of between about 1-6 mil.
25. The sealant of claim 21, further including a temporary tack
decreasing agent on at least one of the upper or lower surface of
the body.
26. The device of claim 21, wherein the at least one release film
is one release film on one of the upper or lower surface of the
sealant and a second release film on the other of the upper or
lower surface of the sealant.
27. The device of claim 21, wherein the release film has multiple
small perforations.
28. The device of claim 21, wherein the release film is dissolvable
in a liquid.
29. The device of claim 21, wherein the release film is heat
meltable.
30. The device of claim 21, wherein the release film is an FEP
(fluorinated ethylene propylene) sheet.
31. The device of claim 21, wherein the release film is
plastic.
32. The device of claim 21, wherein an inert agent is applied to a
surface of the release film which engages the sealant.
33. A method of joining with multiple fasteners, adjacent, inner
and outer overlapping panels of an aircraft fuselage, the panels
having fastener holes, the method comprising the steps of:
obtaining a sealant tape comprising a thin, cured, tacky
polyurethane gel body having a first, tacky polyurethane surface
and a release film on a second cured tacky polyurethane surface;
applying the first, tacky polyurethane surface of the body to an
outer edge of one of either the inner panel or the outer panel of
the overlapping panels; positioning the outer edge of the other
panel of the overlapping panels adjacent the sealant tape such that
an overlap width approximates a sealant tape width; removing the
release film from the second surface of the sealant tape; and
joining the panels with the fasteners so the edges hold the
polyurethane gel body under sufficient compression to cause some
deformation of the polyurethane gel.
34. The method of claim 33, further comprising the step of:
applying an uncured mix of polyurethane gel proximate the
fasteners.
35. The method of claim 33, wherein the release film of the
providing step has multiple perforations therethrough.
36. The method of claim 33, wherein the release film of the
providing step is at least partly coated with release agent.
37. The method of claim 33, wherein the release film of the
providing step is meltable.
38. The method of claim 33, wherein the release film is
plastic.
39. The method of claim 33, wherein the release film is
dissolvable.
40. The method of claim 33, further including the step of, prior to
the joining step, covering at least partly the first surface with a
temporary tack release agent.
41. The method of claim 33, wherein the uncompressed thickness of
the sealant tape is about 12 mil or less and the compressed
thickness is between about 1-6 mil.
42. A device for use with an aircraft assembly having a first part
and a second part, and fasteners, for applying compression to the
two parts, the device comprising: a sealant for receipt between the
parts of the aircraft, the sealant comprising a resilient, cured,
deformable, skeleton-free, polyurethane body having a tacky
polyurethane upper surface and a tacky polyurethane lower surface;
and a skeleton between 1-12 mm thick, the skeleton covered and
encapsulated in the polyurethane body.
Description
[0001] This application claims the benefit of, priority to, and
incorporates herein by reference and is a continuation in part of
U.S. patent application Ser. No. 14/704,030 filed May 5, 2015 which
claims the benefit of Provisional Patent Application No.
61/988,949, filed May 6, 2014; incorporated by reference US
Publication No. 2003/0234498. This application incorporates by
reference and claims the benefit of U.S. application Ser. No.
15/472,859, filed Mar. 29, 2017.
FIELD OF THE INVENTION
[0002] Gaskets, more specifically, a thin, pre-cured gel sealing
member for in one use between two parts in an aircraft, the two
parts under compression, such as a lap joint on a fuselage of an
aircraft, and methods for making an assembly, such as a gasket and
lap joint.
BACKGROUND OF THE INVENTION
[0003] A number of problems may be encountered with sealants. They
must be dimensionally appropriate; they must provide an effective
environmental seal; they must be adapted to receive rivets or other
fasteners; they must maintain resiliency and avoid excessive creep
under load; they must be able to withstand repeated thermal and
pressure cycling; and they must be cost effective taking into
account labor, manufacturing, installation, and in-service. Thus,
typically, prior art sealant materials tend to be a compromise.
[0004] Applicant has heretofore used gaskets, gasket tape, and
other sealants, as well as a method for making gaskets and other
sealants as found and set forth in the following issued patents
that are incorporated herein by reference: U.S. Pat. Nos.
6,530,577; 6,695,320; 7,229,526; and U.S. application Ser. No.
15/472,859. These patents also show uses for tacky polyurethane gel
gaskets in aircraft which are also uses for the sealants disclosed
herein.
[0005] Applicant has found certain problems inherent in the
manufacture and use of very thin polyurethane only (no skeleton)
gaskets. Applicant's disclosures herein solve some of these
problems.
SUMMARY OF THE INVENTION
[0006] Resilient materials are provided for, in some embodiments,
sealing complementary overlapping or closely abutting edges of
aircraft on an aircraft fuselage, such as on lap joints or at other
locations. Air and watertight seals are sometimes created by the
use of cured in-place materials, where two parts are mixed
together, then applied uncured very thinly to a sealing surface,
and allowed to cure after assembly--that is to say, wet installed.
In some assemblies the use of a thin, precured non-adhesive gel,
such as polyurethane gel may be desirable. Applicants have found,
however, that there are difficulties in handling very thin gel, in
particular a gel with either no skeleton or a very thin
skeleton--and less than about 12 mil thick. The gel tends to come
apart very easily as it is tacky and, being thin and lacking
structural integrity (no skeleton embodiments) may stick to the
release paper upon which it is placed.
[0007] A thin, cured gel gasket is disclosed, including methods of
making the thin gel gasket and the use of the thin gel gasket with
aircraft parts, including in an aircraft lap joint. In some
embodiments, the thin gel gasket has no skeleton or other structure
and is comprised of only a stretchable, cured polyurethane gel and
has a thickness of less than 12 mil. The gasket may be manufactured
using a release film that is adapted in a number of ways to make
removal from the gel prior to use easier. In certain methods of
making and using this thin gel gasket, it is applied to a joint or
assembly which is subject to compression, such as, for example, a
lap joint of an aircraft fuselage.
[0008] A joint or assembly for use on an aircraft fuselage is also
disclosed. The joint may include: a first aluminum panel (or one
made of other suitable material) having an outer edge portion; a
second aluminum panel having an outer edge portion; a multiplicity
of rivets, each having a rivet head and rivet shaft, the rivets for
joining the two panels along facing overlapping outer edge
portions; a sealant between the overlapping edge portions, the
sealant comprising a resilient cured polyurethane gel gasket having
a tacky body. In some embodiments, the gasket has a thickness of
less than 12 mil uncompressed. The gasket may have a thickness of
between about 1-6 mil when compressed between the two panels or
other aircraft parts.
[0009] In certain embodiments, at least some of the multiplicity of
rivets may include a tacky polyurethane uncured gel mix on the
shaft thereof. The gel mix may cure after a few minutes. This gel
mix is uncured when first applied. The joint further may include a
temporary tack decreasing agent on a surface of the gasket. The
joint or assembly may, for example, be a lap joint, a double lap
joint, a tapered lap joint or a snap joint.
[0010] An aircraft having a fuselage is disclosed, the fuselage
comprising: multiple partially overlapping panels, the overlap
comprising multiple lap joints; wherein the lap joints comprise
facing surfaces with rivets, the facing surfaces with a thin,
tacky, cured, deformable, resilient polyurethane preformed gasket
therebetween; wherein the compressed gasket thickness is less than
6 mil.
[0011] A method of joining adjacent overlapping panels on an
aircraft fuselage is disclosed, the method comprising: obtaining a
thin, cured polyurethane gasket or gasket tape having a first,
tacky side and release paper on a second side; applying the first,
tacky side to an outer edge of one of either an inner panel or an
outer panel of the overlapping panels; positioning an outer edge of
the other panel of the overlapping panels adjacent the gasket or
gasket tape such that an overlap width approximates a tape width;
removing the release paper from the second side of the gasket or
gasket tape before the following step; and joining the panels with
rivets so the edges hold the gasket or gasket tape under
compression.
[0012] A method of manufacturing a thin gel gasket assembly is also
disclosed. The method may include: providing a release film that
has been adapted to easily release from a thin gel gasket; applying
an uncured mix of the gel to the adapted release film to a
thickness of 12 mil or less; and allowing the gel to cure. The
release film of the providing step, in certain embodiments, has
multiple perforations therethrough. The release film of the
providing step is, in some embodiments, at least partly coated with
release agent. The release film of the providing step is, in
particular embodiments, meltable.
[0013] In an effort to meet environmental sealing problems,
Applicants provide, in certain embodiments, a thin,
polyurethane-only (no skeleton) sealant, gasket or tape as more
particularly set forth below. A method of making and using the same
in a lap joint or other aircraft assembly is also provided.
[0014] In certain embodiments, there is provided a lap joint for
use on an aircraft fuselage. The lap joint may include a first
aluminum panel having an edge portion; a second aluminum panel
having an outer edge portion; a multiplicity of rivets joining the
two panels along complementary overlapping edge portions; a
sealant, such as a tape, for placement between the overlapping edge
portions, the sealant, in one embodiment, consisting essentially of
a cured polyurethane tape gasket having a tacky upper and lower
surface, the gasket having a pre-compression thickness of between
2-12 mil, more preferably, 6-8 mil, wherein the multiplicity of
rivets includes an uncured polyurethane mix applied immediately
upon mixing and before curing to the rivets and/or panel rivet
holes, just before installation of the rivets, wherein optionally a
temporary tack decreasing agent is applied to either or both of the
edge portion(s) of the panels and/or the surfaces of the gasket,
prior to contacting the gasket with the panel(s).
[0015] There is provided, in particular embodiments, a method of
manufacturing a thin, tacky polyurethane gasket. The method may
include: applying a thin film 2-12 mil thick, of an uncured
polyol/isocynate mix to at least one release film that has a low
bonding cohesion with respect to the polyurethane; allowing the
polyurethane to cure; removing the release film; and applying the
gasket to a lap joint of an aircraft.
[0016] The embodiments of the sealant disclosed is tacky, but not
an adhesive. Adhesive based products and gel based sealants differ
in several ways. One of them is not only what their intended use
is, but also in their basic structures, bonding, and physical
characteristics. Adhesives provide a more permanent, rigid and
durable bond as opposed to sealants, such as gels, which are lower
in strength and far more malleable. Sealants are typically not used
to bond parts, such as parts under compression, permanently
together. Adhesives have more power for holding and bonding, but
sealants are good for air and water tight spaces and as gap
fillers. Sealants have lower bonding strength and a higher
elongation percentage than adhesives. Sealants are meant to provide
a watertight seal, but are easily removable when necessary.
Adhesives typically are not meant to be removed from the part to
which they are bonded.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 illustrates a gasket assembly comprising a tacky
polyurethane gasket with release film on one or both sides for use
in making a lap joint.
[0018] FIGS. 2A, 2B, and 2C illustrate a method of making a tacky
polyurethane gasket for use in a lap joint or other assembly.
[0019] FIGS. 3A, 3B, and 3C illustrate a gasket having a bottom or
top film that is perforated or mesh-like (FIG. 3A,); dissolvable
(FIG. 3B); or, heat meltable (FIG. 3C).
[0020] FIG. 3D illustrates a gasket assembly comprising two release
films, one on the top and one on the bottom of a thin, cured tacky
polyurethane gasket.
[0021] FIGS. 4A, 4B, 4C, 4D, 4E, 4F, 4G, and 4H illustrate a method
using applicant's thin skeleton-less gasket on an aircraft fuselage
to create a lap joint.
[0022] FIG. 5A illustrates in isometric view another method for
making a thin polyurethane gasket.
[0023] FIG. 5B illustrates a method of preparing a bottom film so
that it releases cleanly from a polyurethane that has cured on
it.
[0024] FIGS. 5C and 5D illustrate a device for and method of
obtaining a controlled thickness on a thin polyurethane sealing
member.
[0025] FIGS. 6A, 6B and 6C illustrate additional uses of
applicants, then gasket, namely a double lap joint, a tapered joint
and a snap joint, respectively.
[0026] FIGS. 7A, 7B, 7C, 7D, and 7E illustrate uses of Applicant's
novel sealants disclosed herein.
[0027] FIGS. 7C1, 7C2, and 7C3 all illustrate a lap patch which
uses embodiments of Applicant's sealants disclosed herein.
[0028] FIGS. 8A and 8B illustrate the use of Applicant's sealants
disclosed herein with a titanium heat shield.
[0029] FIG. 9 illustrates the use of Applicant's sealants disclosed
herein with joints comprised at least in part of laminated
composites.
[0030] FIGS. 10A and 10B illustrate a two-part sealant that comes
in a cartridge for use with a spray gun, the two-part sealant
forming a mix that will cure to a tacky gel.
[0031] FIG. 10C illustrates a fitted part on which a tacky
polyurethane gel has been sprayed and a cover has been applied.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0032] Applicant provides, as seen in FIGS. 1, 2D, 3D, 4G, and 4H,
for example, a gasket assembly 10, including a gasket 12, the
gasket comprised of tacky, cured polyurethane for use, in one
embodiment, in a lap joint 11 (see FIGS. 4D and 4F). A lap joint 11
may include a first panel A and a second, adjacent panel B, the two
panels of an aircraft fuselage overlapping and riveted together
with a series of rivets R (or other attaching hardware) and with
gasket 12 therebetween. Gasket 12 will create an effective
environmental seal and help prevent corrosion of the panels at the
joint. In a preferred embodiment, gasket 12 is, prior to placement
on the workpiece, is part of the gasket assembly 10 which includes
a release film 14 on at least one side thereof, the other side
being tacky (see FIG. 1) or having a release film 14 on both sides.
In one form, a thin, cured polyurethane gasket 12 is provided (see
FIG. 3D). As further set forth below, release film 14 is not placed
between the two overlapping riveted panels, but is simply useful in
handling, prior to placement of gasket 12 on the workpiece, of
gasket assembly 10 as the polyurethane of gasket 12 may be tacky
and tacky or dimensionally somewhat unstable. The release film is
removed after the tacky side is attached to the workpiece surface
as set forth in more detail below. Thus, gasket assembly 10 is used
to refer to gasket 12 having at least one release film 14 on the
upper or lower surface thereof or on both surfaces.
[0033] Gasket 12, in one embodiment, has an uncompressed thickness
of about 2 to 12 mil or, more preferably, about 6 to 8 mil, which
thickness is the thickness as applied (see FIG. 4B) prior to any
compression between members A and B of the lap joint or other
aircraft assembly. Compression between the panels may cause some
thinning and squeeze out as gasket 12 is both tacky, deformable and
subject to flow or squeeze out 42 under compression, see FIG. 4E.
Compressed thickness as, for example, in a lap joint, may be less
than about 6 mil.
[0034] The composition of gasket 12 may be found in the patents
incorporated herein by reference and is typically pre-cured, that
is, cured prior to placement between panels A and B (see FIG. 4F)
in a manner more specifically set forth below. Some of the patents
incorporated herein by reference are: U.S. Pat. Nos. 6,530,577;
6,695,320; and 7,229,516. In preferred embodiments, there is no
skeleton in gasket body 12. Handling and making the gasket with
polyurethane gel that is both tacky and is thin as set forth in the
ranges set forth above, creates some unique problems that are
typically not present in dealing with polyurethane gaskets that are
thicker, such as those having bodies between about 15 and 55 mil
thickness, for example.
[0035] A. Methods of Making the Thin Gasket
[0036] One of the difficulties in working with a thin polyurethane
gasket is in the manufacture of the gasket. FIGS. 2A, 2B, and 2C
illustrate a method of manufacturing gasket assembly 10 that may
overcome some of these difficulties. Gasket assembly 10 is seen to
be, in one embodiment elongated, in the nature of a tape having a
quite a small thickness range, a larger width, and an even
substantially larger length. Width may be, for example, about 0.05
inches to 18 inches, and length may be about 80 inches to 218
inches.
[0037] In one embodiment, a flat, level mold 18 is provided having
a bottom wall and side walls 20 and an open top. The mold may be
about 2' wide and about 12' long. A bottom film 16 (a release film
designated with 16 because of its placement beneath uncured mix) of
release film or non-release film is laid either across the bottom
or across the bottom and at least partially up the sides of the
mold. In one embodiment, a two-part polyurethane comprising a
polyol 24 and an isocyanate 26 is injected into mold 18 using a
mixing cartridge 22 that has a nozzle 22a for mixing the two parts.
The volume of the mix injected is known and set so that it provides
the selected body thickness, for example, about 6 to 8 mil or in
the range of 2-12 mil. The mix will chemically react and set (cure)
at ambient temperature in mold 18 on top of bottom film 16.
Typically, the cure (to about 90%) of final hardness occurs in
about 30 to 90 minutes. Before it sets, it, being self-leveling,
the mix will be spread out or may be leveled with a handheld
straight edge. Bottom film 16 is provided for the releasing,
post-curing of the tacky gasket polyurethane material from the
mold.
[0038] FIG. 2B illustrates the cured polyurethane which cured upon
bottom film 16 and upon which, after it is cured, a second release
film 14 may be placed as a top film. Removal of polyurethane gasket
body 12 with bottom film 16 attached thereto may be achieved as by
manually lifting out. Following removal, a sharp knife may be used
to produce a number of smaller width tape strips--for example,
about twenty four one-inch strips.
[0039] It has heretofore been difficult to remove the release films
from a thin polyurethane gel gasket 12. In an effort to help
achieve clean removal of the release film, several solutions are
set forth below.
[0040] B. Physical Configuration or Chemical Composition of the
Film
[0041] In FIG. 3A, a first specific embodiment 16a of bottom film
16 is shown to be perforated with multiple small holes 17 and thus
may be removed more easily than if it were a solid film. In the
same form, this may be used as a release film on the top surface of
the cured gel also.
[0042] In FIG. 3B (shown with gasket assembly inverted after
removal from the mold to show bottom film 16 on top), a second
specific embodiment 16b of film 16 is provided with water or
chemical dissolvability. For example, water from a spray container
28 or damp cloth 30 may be applied to such dissolvable film and the
film allowed to dissolve. This is in lieu of a mechanical
separation as used in FIG. 3A above, with perforated film 16a.
Adhesive Research provides a dissolvable film, including a water
dissolvable film, that may be tailored in thickness, dissolution
rate, texture, and tensile strength (see www.adhesiveresearch.com).
Rice paper may also be used, as it is dissolvable in water and
non-toxic.
[0043] In FIG. 3C, a heat meltable film 16c is provided as a bottom
film for the manufacturing of a thin polyurethane gel gasket.
Following removal of the gasket assembly from the mold 18, a heat
lamp or other heat source 32 may be provided on or adjacent heat
reactive meltable film 16c to remove it from gasket 12. In one
embodiment, the heat meltable film melts at below about 275.degree.
F.
[0044] FIG. 3D illustrates that when gasket body 12 is removed from
a mold and a bottom film removed from the surface thereof, a second
release film 14 may be placed on the cured top surface so it is
easy to handle by a user. This second release film is placed on
cured gel so its removal may not be as problematic as film 16. In
one embodiment, the top release film is in the same nature as
bottom film 16 or it may be made from another material such as FET.
While some embodiments use release film and agents disclosed herein
are used with thin gaskets or skeleton-free gasket, they may be
used with gaskets from 13 to 75 mil thick with or without
skeleton.
[0045] In some embodiments (see FIG. 4H), the thin gel gasket has a
very thin skeleton 13, encapsulated in the gel such as embodiment
of a skeleton found in U.S. application Ser. No. 14/484,570, filed
Sep. 12, 2014 (see FIG. 4H). A thin gel gasket may also have or
thin skeleton, in some embodiments the skeleton in range of 2-12
mil in a body about 12 mil or less (uncompressed) (see FIG. 4H).
The skeleton may be metal or non-metal. Metal skeletons may be made
from aluminum, stainless steel, bronze, monel, and copper
(including any alloys of these metals) and may be a mesh (woven
from metal fibers or strands) or may be expanded metal sheet.
Non-metal may be woven mesh, molded or extruded and may be any
skeleton found in the U.S. application Ser. No. 14/484,570, filed
Sep. 12, 2014, and US Publication No. 2003/0234498, which are
incorporated by reference, but has numerous holes or openings for
the gel to fill.
[0046] C. The Use of a Release Agent Applied to the Release
Film
[0047] FIG. 5A illustrates a preferred alternate embodiment of
making a very thin polyurethane-only tape, wherein no mold is used,
just a flat bottom film 16, which may be a bottom film with any of
the clean release qualities set forth herein. A two-part polyol
isocyanate mix 24/26 is applied to the top surface of the bottom
film 16. It may be applied in a known volume on a bottom film
marked by a rectangle or other shape. The rectangle will show the
area on which to spread the known volume of mix to give the desired
"thinness." An S-shaped motion of handheld mixing cartridge 22 will
help application of the mix and a handheld straightedge may be used
to help level--though in a preferred embodiment, the mix may be
self-leveling. It will spread out somewhat and typically is applied
(uncured) in an elongated stream (with a consistency similar to
motor oil) and will start to set up and cure after it has spread
out "width-wise."
[0048] By controlling the speed at which one moves the mixing
cartridge across the film and the rate of mix application, one can,
with experience, obtain a thin, relatively wide strip. A top film
may be placed on it, for example, after curing. Then it may be cut
in multiple strips, lengthwise, to the desired width. In either
method, leveling and a selected "thinness" may be further
controlled by using a rigid roller 40 having end ridges 41, such as
that shown in FIGS. 5C and 5D. This is done with a top release film
in place and before the mix is fully cured. In an alternate method,
the roller may be made from or coated with a polyurethane non-stick
material.
[0049] FIG. 5B illustrates another manner in which release may be
obtained from the polyurethane mix that cures in place on bottom
film 16. In this application, a release agent 27 in liquid, dust or
other suitable form may be applied to the bottom film before the
uncured mix is applied thereto. Such an agent should be inert and
non-volatile as regards to the polyurethane and may be applied with
a brush 29, a spray application 28 or any other suitable method.
One such material that may be applied is a hydrophobic material
known as Rain-X.RTM.. Another is sold under the trademark PAM.RTM..
PAM.RTM. is made from a vegetable oil, typically canola oil, and
Rain-X is a hydrophobic silicon polymer that also helps with
release of cured polyurethane gel. The primary active ingredients
in Rain-X are polysaloxines. In one embodiment, films 14/16, for
example, when used with the method set forth in FIG. 5A above, may
be glass, plastic or FET with Rain-X or other release agent 27
applied thereto, which Rain-X bonds well with the glass, but does
not bond the polyurethane and thus allows easy release. Other
release agents are wax, oil and other compositions as set forth in
Publication No. US 2009/0020917, which publication is incorporated
herein by reference.
[0050] Certain types of release film may work by being physically
altered, chemically altered or receiving a release agent on the
surface thereof as set forth in FIG. 5B. These include: Teflon,
PET, PVC, PP, nylon, FEP (fluorinated ethylene propolene), and
polyurethane. Any of the foregoing or any other film may be adapted
as set forth herein.
[0051] D. Joint or Other Aircraft Assemblies Using Applicant's Thin
Polyurethane Gel Sealant
[0052] FIGS. 4A-4G illustrate a lap joint 11 wherein a single-sided
tacky (release film on one side only) tape embodiment may be
applied along a complementary edge of panel A, such as aluminum
panel of the fuselage of an aircraft. The edge of gasket 12 is
aligned with the edge of the panel. The bottom side is tacky
polyurethane and will immediately adhere to the location at which
it is placed with only a minimal ability to move it after it
touches. This requires careful alignment and placement of the tape,
tacky side down. However, the placement of the gasket may be less
critical, if the edge of panel A and panel B, or the surfaces of
gasket 12, are first treated with a temporary tack reduction
material 37, FIG. 4B. This renders them temporarily non-tacky to
the polyurethane. Temporarily is in the nature of minutes,
typically, up to about 5-20 minutes, during which there may be some
relative movement between gasket body 12 and either the lower
and/or the upper panels. This ability to move allows careful
alignment of the gasket along one panel and careful alignment of
the second panel with respect to the first panel and the gasket.
Alignment is especially important if the panels are pre-drilled for
the placement of rivets (or other attaching hardware) therein and,
thus, require careful alignment of the rivet holes.
[0053] FIG. 4B shows a container of such temporary tack reduction
material 37, which may be applied to both the underside of panel B
or the upper surface of gasket 12 or (not shown) the upper surface
panel A or the bottom surface of the gasket before it is applied.
Application may be by any means, such as brush, spray, cloth (wipe
on) or a thin film or a solid liquid or the like.
[0054] The compositions that may be used in this step illustrated
in FIG. 4B include the aforementioned compositions used for
treating the surface of the bottom film. They are typically
non-reactive to aluminum or other metals and, thus, usually contain
no acids and are inert and non-volatile. While the ability to do
some "post contact" adjustment of the workpieces (panels A and B)
with respect to the tacky, thin gasket is important, the nature of
the compositions applied to the various surfaces to allow one to
make alignment adjustments. Applicants' gasket is deformable and
flows somewhat under compression and therefore spreads. Any
temporary tack reduction material 37 or release agent 27 should not
contain any material that would cause corrosion or inhibit the
environmental seal that tacky, cured polyurethane produces between
the adjacent compressed panels. Isopropyl alcohol is one temporary
tack reduction material 37 that may be applied by spraying, in one
embodiment that will help temporarily inhibit the stickiness
between the workpiece and gasket 12.
[0055] FIGS. 4C and 4D illustrate that, after alignment of the
holes for the receipt of rivets 36 (or other attaching hardware), a
wet seal 34 may be applied from an applicator 33. In one
embodiment, wet seal 34 may be an uncured two-part polyurethane mix
24/26, which mixes in the nozzle of the applicator, which will cure
in place at ambient temperature when applied around the rivet hole
before or during the insertion of the rivets (or other attaching
hardware) through the holes with the gasket 12 lying therebetween.
Such a wet seal, such as Self Leveling Green or Self Leveling Red,
is available from AVDEC located at 1810 Mony Street, Fort Worth,
Tex. 76102. It is applied to and around the rivet holes and/or on
the rivet prior to affixing the rivet between the two panels A/B
and will help, after curing, create a good environmental seal and
help prevent liquids or moisture from accessing to the space around
the rivet holes between the panels, where they overlap through the
rivet holes. Indeed, the wet seal may be used for creating the lap
joint. Even when no gasket is used.
[0056] FIG. 4D illustrates lap joint 11 where panels A and B may be
under compression between their edge portions. Compression
typically occurs during the process of fastening the rivets to the
panels. Because Applicant's thin polyurethane gel gasket 12 is
relatively soft, squeeze out 42 may occur at the lap joint edges is
seen in FIG. 4E. A cloth 30 that may be soaked with isopropyl
alcohol or other appropriate medium may be used to wipe down the
squeeze out to give a tapered edge (see FIG. 4G) or flat, which
conforms to the panel edges (see FIG. 4D).
[0057] Additional embodiments appropriate for receiving applicants
thin skeleton less gasket conclude include double lap joints FIG.
6A, tapered lap joints, FIG. 6B, and snap joints, FIG. 6C. The
aluminum of the joints may be aluminum alloy or any other material,
lap joint referring to the physical position of the overlapping
panels. While the term "gasket" is used, with a tape being a gasket
with a particular geometry, a gasket may be a pre-cured sealant for
placement between two pieces. Lap joints are used in many
manufacturing processes and in a number of vehicles, including
trains and motor homes. The overlapping sections, such as aluminum
panels, may be treated or untreated. If treated, it may have a
conversion coating (for corrosion control) or a paint coating (may
include a corrosion inhibiting primer).
[0058] Other non-lap joint aircraft parts or assemblies that may
use the sealants disclosed herein include aircraft antennas,
between floorboards and floorboard support structures, between
window seat tracks and window seat floors where wing lugs join
fuselage lugs, in electronic equipment bays where electronic
equipment rests in racks, on a floor or shelves (where moisture can
collect and cause corrosion), where dissimilar metals meet to help
prevent galvanic corrosion, conductive and non-conductive thin gel
washers or tapes for EME (electromagnetic environment) grounding or
isolating metal or electronic elements, including conductors and/or
grounds, on electrical and structural aircraft systems. Any of the
sealants disclosed herein may also be used in EME areas, electronic
sources and fixtures. Applicant's sealants can be used on or around
radio transmitters, receivers, oscillators, motors, lamps, energy
ignition relays, heaters, computers, and peripherals and the
like.
[0059] FIGS. 7A, 7B, 7C, 7D, and 7E illustrate additional uses of a
thin gel only or thin gel with thin skeleton on, with or as part of
an aircraft assembly. FIG. 7A illustrates any embodiments of
Applicant's sealant disclosed herein between the underside of an
aircraft wing and an aircraft pod, which pod may carry fuel or
electronics or anything else. FIG. 7B illustrates an aircraft
interior showing an aircraft floor where any embodiment of
Applicant's sealant as disclosed herein is used between an avionics
box or other structure mounted to the floor and/or a seat track
mounted to the aircraft floor. FIGS. 7C and 7D illustrate a lap
joint or battle damage repair, such as may be required when a
bullet or shrapnel hole is torn into the aircraft outer skin and/or
structural members. FIG. 7C illustrates a structural member with
any of the embodiments of Applicant's sealant between the aircraft
skin and the structural member to which the aircraft skin mounts.
In FIG. 7D, any of the sealants that Applicant's disclosed herein
is applied to the recess or border area before a patch panel is
installed with fasteners, such as rivets or the like. FIG. 7E is a
cross-sectional view of the patch of FIG. 7D.
[0060] FIGS. 7C1, 7C2, and 7C3 are additional drawings of an ABDR
(aircraft battle damage repair) or a lap joint repair. FIG. 7C1
shows a first or outer patch and a second or inner patch (dashed
lines) with the sealant between the holes shown in dashed lines. In
other words, the aircraft skin in the border area adjacent the hole
receives an outer patch and an inner patch (or at least one) with
fasteners therethrough to reinforce the hole. Applicant's sealant
may be between the outer patch and the skin border area or between
the inner patch and the skin border area, but typically is between
both the outer patch and the skin border area and the inner patch
and the skin border area, and fasteners, such as rivets, can be
used between the outer and inner patch. FIG. 7C2 shows an inside
view of a patch, which in this embodiment, may be a single patch
reinforcing an area around battle damage. FIG. 7C3 shows another
view, close up, of FIG. 7C2, showing the gel of the deformable gel
sealant oozing out between the aircraft skin and the inner
patch.
[0061] FIG. 7E shows an inside the aircraft patch, also known as a
doubler, with a filler patch (typically flush) on the outside where
the hole in the aircraft skin is located. Any of the sealants
disclosed herein may be used as illustrated between the inside
patch or the doubler and the skin border area around the hole. In
some cases, a sealant may be used between the filler patch also and
structural fastener elements may be provided as indicated.
[0062] FIGS. 8A and 8B illustrate the application of any of the
thin sealants combined herein to an auxiliary powered unit heat
shield, such as an APU heat shield used on the co-pilot side of a
British Aerospace 146 cockpit. FIG. 8A shows the shield with a hole
for the exhaust, which shield has a thin gel sealant on the either
or both surfaces thereof. FIG. 8B illustrates how the shield can be
placed over areas of corrosion or areas where corrosion is likely
to occur on an aircraft skin or an aircraft member with the gel
between the skin/member and the heat shield.
[0063] FIG. 9 illustrates the use of Applicant's thin gel sealants
with composites as in aircrafts that are made from composites,
including, for example, the Boeing Dreamliner. Applicant's thin gel
may be used in a composite to composite joint, a composite to an
aluminum joint, a composite to titanium joint or a composite to a
steel or other material joint. Typically, the joints are held
together with fasteners rather than adhesive bonded. The thin gel
sealant disclosed herein may be applied prior to assembly of the
joint or during repair and/or replacement of one or more parts of
the joint. The joint may be held together with fasteners known in
the art, rivets, bolts, and nuts or the like. Applicant's thin gel
sealant may be used in place of adhesively bonded joints or may be
used in joints that do not necessarily need to be strong in shear.
Moreover, Applicant's thin gel sealants may be especially used for
non-bonded joints which require removability. Bolted or riveted
joints (mechanically fastened) in fibrous composite structures may
be appropriate for Applicant's thin gel sealants.
[0064] Areas where Applicant's thin gel sealant may be applied,
either as a cured, tacky gel gasket or spray-on cure-in-place (see
below), include between the faying surfaces of the following types
of joints: bonded doubler; unsupported single lap joint; single
strap joint; tapered single lap joint; double lap joint; double
strap joint; tapered strap joint; stepped lap joint; and scarf
joint (see
NIAR.wichita.edu/nairworkshops/portals/0/jun17_0345_stevew_dh.pdf,
incorporated herein by reference), NSE Composites, page 4, article
entitled "Composite Bonded Joints Analysis, Data and
Substantiation," Jun. 16-18, 2004, D. M. Hoyt and Steve Ward, NSE
Composites, Seattle, Wash. While these show bonded joints, the use
of Applicant's thin gel sealants provide for non-bonded joints that
are fastener held (mechanically bonded rather than adhesively
bonded), where the joints are under compression but, with
Applicant's novel sealant compositions, removability is retained,
though some shear strength is sacrificed. In some embodiments,
Applicant's thin gel sealants are used with bolted composite
structures, that is, non-adhesive joints (adhesive bond joints),
Applicant's sealants provide removability and good environmental
seal. Some mechanically fastened permanent or removable joints may
be found in U.S. Pat. No. 7,678,437, incorporated herein by
reference.
[0065] Adhesive based products and gel based sealants differ on
several scales. One of them is not only what their intended use is,
but also in their basic structures, bonding, and physical
characteristics. Adhesives provide a more permanent, rigid and
durable bonding as opposed to sealants, such as gels, which are
lower in strength (including shear) and far more malleable.
Sealants are typically not used to bond things permanently
together. Adhesives have more power for holding and bonding, but
sealants are good for air and water tight spaces and as gap
fillers. Sealants have lower bonding strength and a higher
elongation percentage than adhesives. Sealants are meant to provide
a watertight seal, but are easily removable when necessary.
Adhesives typically are not meant to be removed.
[0066] E. A Tacky Sprayable Polyurethane Cure in Place Sealant
[0067] While the embodiments set forth above illustrate a thin gel
(gel only or gel with a thin skeleton), sealant or gasket, in some
embodiments, with a gasket body having a release film engaged
therewith, Applicant may also provide for a sprayable tacky sealant
that comes in a two-part cartridge 102 for use with a pneumatic gun
104 (see WO 2017/172906 entitled "A Clear Sprayable Sealant for
Aircraft Parts and Assemblies"; see also PCT/US2017/024735,
incorporated herein by reference).
[0068] FIG. 10A (FIG. 11 in the '906 International Publication)
shows pneumatic gun 104 that has engaged therewith a two-body
cartridge. The cartridge is fitted into the pneumatic gun and air
pressure forces the two separate parts of the gel components
(typically a polyol and diisocynate) to mix in the mixing nozzle
104a and to be emitted from the tip of the nozzle in an atomized,
uncured polyurethane spray. Such a polyurethane spray can be used
to spray a workpiece, which may have a flat section or may include
a gap. The workpiece may be masked off, which workpiece can then be
used as one part of the two-part joint, which two parts of a joint
"sandwich" the thin tacky gel spray-on layer therebetween, and
which two pieces may be held under compression as with the use of
fasteners. If a gap is present, the pneumatic spray gun may be
moved closer to fil the gaps with thicker gel. Any overspray beyond
the two parts under compression may be removed with a clean,
alcohol soaked cloth. The sealant is a cure-in-place tacky gel,
which may or may not be clear, created from a two-part polymer mix
applied with a pneumatic mix and spray gun. It may be applied as
thin gel (12 mil or less thick) or thicker--up to 50 mil in some
applications. The two parts are kept separate until application
where they mix in the mixing nozzle 104a, may be used to form a
gasket or sealant that is gel only and in the thickness ranges
disclosed herein. In addition, the workpiece, prior to spraying,
may be overlaid with a skeleton (metallic or non-metallic, any
skeleton disclosed herein), which may be taped or otherwise fixed
in place, and upon which the spray can be applied (see FIG. 10B).
When the mix sets up to form a tacky gel, it will hold the skeleton
and a second piece may be fastened to it. Applicant's spray mix may
be used between faying surfaces and as a gap filler on laminated
composites or metal structures, including mixed composite/metal
joints. FIG. 10C illustrates the use of the tacky spray on a pitted
surface, such as pits caused by corrosion on a part, on which the
sprayable gel has been applied as a pit filler. A flat cover or
second part may be applied and the inherent tack may hold the part
in place. Or, fasteners may be used, with little or no compression
generated. One two-part cartridge that may be used to apply the
two-part sprayable is Part Number CS-5410-1 available from KBS
Chemical, Dodd City, Tex.
[0069] Although the invention has been described with reference to
specific embodiments, 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.
* * * * *
References