U.S. patent application number 16/088175 was filed with the patent office on 2020-09-24 for fabric-backed roofing membrane composite.
This patent application is currently assigned to Firestone Building Products Company, LLC. The applicant listed for this patent is FIRESTONE BUILDING PRODUCTS COMPANY, LLC. Invention is credited to Brian ALEXANDER, Joseph R. CARR, Michael J. HUBBARD, Joseph KALWARA, Jiansheng TANG, Todd D. TAYKOWSKI, Carl E. WATKINS, JR..
Application Number | 20200299966 16/088175 |
Document ID | / |
Family ID | 1000004917447 |
Filed Date | 2020-09-24 |
United States Patent
Application |
20200299966 |
Kind Code |
A1 |
TANG; Jiansheng ; et
al. |
September 24, 2020 |
Fabric-Backed Roofing Membrane Composite
Abstract
A membrane composite comprising a membrane panel having opposed
first and second planar surfaces and a fabric backing secured to a
first planar surface through a UV-cured adhesive disposed on said
planar surface of said membrane.
Inventors: |
TANG; Jiansheng; (Carmel,
IN) ; HUBBARD; Michael J.; (Murfreesboro, TN)
; KALWARA; Joseph; (Indianapolis, IN) ; WATKINS,
JR.; Carl E.; (Mount Juliet, TN) ; ALEXANDER;
Brian; (Westfield, IN) ; TAYKOWSKI; Todd D.;
(Lebanon, TN) ; CARR; Joseph R.; (Indianapolis,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FIRESTONE BUILDING PRODUCTS COMPANY, LLC |
Nashville |
TN |
US |
|
|
Assignee: |
Firestone Building Products
Company, LLC
Nashville
TN
|
Family ID: |
1000004917447 |
Appl. No.: |
16/088175 |
Filed: |
March 25, 2017 |
PCT Filed: |
March 25, 2017 |
PCT NO: |
PCT/US2017/024190 |
371 Date: |
September 25, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62313225 |
Mar 25, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 27/32 20130101;
B32B 25/10 20130101; E04D 5/148 20130101; B32B 27/06 20130101; B32B
7/12 20130101; B32B 2262/0284 20130101; B32B 5/24 20130101; B32B
25/04 20130101; B32B 27/12 20130101; B32B 2419/06 20130101; B32B
2262/101 20130101; E04D 5/06 20130101; B32B 5/022 20130101; E04D
5/08 20130101 |
International
Class: |
E04D 5/14 20060101
E04D005/14; E04D 5/08 20060101 E04D005/08; E04D 5/06 20060101
E04D005/06; B32B 7/12 20060101 B32B007/12; B32B 5/02 20060101
B32B005/02; B32B 5/24 20060101 B32B005/24; B32B 25/04 20060101
B32B025/04; B32B 25/10 20060101 B32B025/10; B32B 27/06 20060101
B32B027/06; B32B 27/32 20060101 B32B027/32; B32B 27/12 20060101
B32B027/12 |
Claims
1. A membrane composite comprising: i. a membrane panel having
opposed first and second planar surfaces; and ii. a fabric backing
secured to a planar surface through a cured adhesive disposed on
said planar surface of said membrane.
2. The membrane of claim 1, where said membrane panel includes a
width defined between a first lateral edge and a second lateral
edge, and where said fabric backing extends across a portion of
said width, thereby providing an exposed planar surface of said
membrane panel.
3. The membrane of claim 1, where said adhesive extends across the
entire width of the membrane panel.
4. The membrane of claim 1, where the adhesive is UV cured.
5. The membrane of claim 4, where the adhesive is an acrylic-based
hot-melt adhesive.
6. The membrane of claim 5, where the adhesive is a
polyacrylate.
7. The membrane of claim 1, where the fabric backing is a fleece
backing.
8. A method for preparing a membrane composite, said method
comprising: i. providing a polymeric membrane having opposed planar
surfaces; ii. applying a curable adhesive onto a planar surface of
the membrane to form a curable layer; iii. curing the curable layer
to formed a cured layer; and iv. after said step of curing,
applying a fabric to the cured layer.
9. The method of claim 8, where said membrane includes a width
defined between a first lateral edge and a second lateral edge, and
where said step of applying a curable adhesive onto a planar
surface of the membrane includes applying the adhesive to only a
portion of the planar surface to thereby provide an exposed planar
surface of said membrane panel.
10. The method of claim 8, where said step of applying an adhesive
includes melt extruding the adhesive onto the planar surface of the
membrane.
11. The membrane of claim 8, where said membrane includes a width
defined between a first lateral edge and a second lateral edge, and
where said step of applying a curable adhesive onto a planar
surface of the membrane includes applying the adhesive across the
entire width of the membrane.
12. The membrane of claim 10, where said step of curing includes UV
curing.
13. The membrane of claim 12, where the adhesive is an
acrylic-based hot-melt adhesive.
14. The membrane of claim 13, where the adhesive is a
polyacrylate.
15. The membrane of claim 8, where the fabric is a fleece backing.
Description
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 62/313,225, filed on Mar. 25, 2016, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention are directed toward
fabric-backed (also known as fleece-backed) roofing membranes
wherein the fabric backing is adhesively secured to the membrane
through a cross-linked adhesive that is applied to the membrane as
a hot-melt.
BACKGROUND OF THE INVENTION
[0003] Flat or low-sloped roofs can be covered with polymeric
membranes such as EPDM membranes. The membranes can be secured to
the roof using several attachment mechanisms including ballasting,
mechanical attachment, and adhesive attachment. Attachment of the
membrane to the roof is important because the membranes can be
subjected to severe wind uplift forces.
[0004] Adhesive attachment is typically employed to form adhered
roofing systems. The membrane may be adhered to the roof substrate
substantially across the entire planar surface of the membrane to
form fully-adhered systems. Fully-adhered roofing systems are
advantageously installed where maximum wind uplift prevention is
desired. Also, fully-adhered systems are desirable in re-roofing
situations, especially where the new membrane is placed over an
existing membrane (a technique that is commonly referred to as
re-skinning).
[0005] Several techniques are employed to prepare fully-adhered
roofing systems. One technique includes the use of a fleece-backed
EPDM membrane that is secured to the substrate by using a low-rise
polyurethane foam adhesive that is sprayed over the substrate. Once
the adhesive polyurethane foam is applied, the fleece-backed
membrane is applied to the adhesive layer, which attaches itself to
the fleece backing. Alternatively, nitrile-based bonding adhesive
can be applied to the substrate and the fleece-backed EPDM membrane
can be secured thereto.
[0006] While fleece-backed membranes typically offer superior
wind-uplift resistance, which superiority stems from the strong
adhesive bond formed between the fleece and the adhesive applied to
the roof surface, a potential point of failure is the adhesion
between the fleece and the membrane. In the case of thermoplastic
membranes, the fleece is often attached to the membrane by heating
or partially melting the membrane and mating the fleece to the
membrane while in its molten or partially molten state. In a case
of thermoset membranes, such as EPDM membranes, the fleece is often
attached by employing a hot-melt adhesive. For example, it is
common to employ ethylene vinyl acetate as an adhesive to secure
the fleece to the membrane. In either event, extreme temperatures
can negatively impact the adhesion between the fleece and the
membrane. For example, in the case of ethylene vinyl acetate, as
the membrane temperature nears the softening point of the ethylene
vinyl acetate, the adhesive forces could be compromised.
SUMMARY OF THE INVENTION
[0007] One or more embodiments of the present invention provide a
membrane composite comprising a membrane panel having opposed first
and second planar surfaces and a fabric backing secured to a planar
surface through a UV-cured adhesive disposed on said planar surface
of said membrane.
[0008] Other embodiments of the present invention provide a method
for preparing a membrane composite, said method comprising (i)
providing a polymeric membrane having opposed planar surfaces, (ii)
applying a curable adhesive onto a planar surface of the membrane
to form a curable layer, (iii) curing the curable layer to formed a
cured layer, (iv) applying a fabric to the cured layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a cross-sectional side view of a fabric-backed
roofing membrane composite according to aspects of the
invention.
[0010] FIG. 2 is a cross-sectional side view of a roofing composite
employed in alternate embodiments of the present invention.
[0011] FIG. 3 is a cross-sectional of a side view of a roofing
composite employed in alternate embodiments of the present
invention.
[0012] FIG. 4 is a cross-sectional side view of a roof system
according to embodiments of the present invention.
[0013] FIG. 5 is a flow chart describing a process for making
membrane composite according to embodiments of the present
invention.
[0014] FIG. 6 is a schematic of a continuous process for making
membrane composite according to the present invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0015] Embodiments of the invention are based, at least in part, on
the discovery of a roofing membrane composite including a fabric
backing adhered to a polymeric membrane through a cross-linked
adhesive that is applied to the membrane as a hot-melt. While the
prior art employs holt-melt adhesives to secure fabric backing to
membranes, use of the adhesive proposed by the present invention
provides superior bond strength at elevated temperatures without
compromising other attributes of the composite system.
Membrane Composite
[0016] A membrane composite according to embodiments of the present
invention can be described with reference to FIG. 1, which shows
membrane composite 11 including polymeric planar body 21, adhesive
layer 31, and fabric backing 41. Planar body 21 includes top planar
surface 23, bottom planar surface 25, first lateral edge 27, and
second lateral edge 29. Adhesive layer 31, which is a
pressure-sensitive adhesive as described herein, is disposed on
bottom planar surface 25 along at least a portion of the width of
planar body 21. Fabric backing 41 is adhesively mated to planar
body 21 through adhesive 31. As suggested in FIG. 1, the area of
bottom surface 25 of planar body 21 carrying fabric backing 41 can
be secured to a roof substrate through fabric backing 41, and
therefore this area may be referred to as roof-surface contacting
portion 61. That area of bottom surface 25 of planar body 21 that
may be exposed (i.e. does not include adhesive 31 nor fabric
backing 41) may be referred to as lap area 51.
[0017] An alternate embodiment of the membrane composites of the
present invention may be described with reference to FIG. 2, which
shows composite 12 including polymeric planar body 21, adhesive
layer 31, which is a pressure-sensitive adhesive as described
herein, fabric backing 41, and release member 71. Planar body 21
includes top planar surface 23, bottom planar surface 25, first
lateral edge 27, and second lateral edge 29. Adhesive layer 31,
which is a pressure-sensitive adhesive as described herein, is
disposed on bottom planar surface 25 and extends the entire width
of planar body 21 from first lateral edge 27 to second lateral edge
29. As with the embodiments in FIG. 1, fabric backing 41 partially
extends across the width of planar body 21 thereby leaving exposed,
at surface 33, a portion of adhesive layer 31. In lieu of fabric
backing 41, a release member 71 may be removably affixed to
adhesive layer 31 at surface 33. As a skilled person will
appreciate, composite 12 can be secured to a roof substrate through
fabric backing 41, and therefore this area of composite 12 may be
referred to as roof-surface contacting portion 61. That portion of
adhesive layer 31 represented by surface 33, and which may be
covered with release member 71, can be employed to form a lap seal
between overlapping, adjacent membranes.
[0018] An alternate embodiment of the membrane composites of the
present invention may be described with reference to FIG. 3, which
shows composite 13 including polymeric planar body 21, adhesive
layer 31, which is a pressure-sensitive adhesive as described
herein, fabric layer 41, external adhesive layer 55, and release
member 57. Planar body 21 includes top planar surface 23, bottom
planar surface 25, first lateral edge 27, and second lateral edge
29. Adhesive layer 31, which is a pressure-sensitive adhesive as
described herein, is disposed on bottom planar surface 25 and
extends the entire width of planar body 21 from first lateral edge
27 to second lateral edge 29. Fabric layer 41 is mated to adhesive
layer 31 and can extend the entire width of planar body 21 from
first lateral edge 27 to second lateral edge 29. External adhesive
layer 55, which is a pressure-sensitive adhesive as described
herein, is disposed on fabric layer 41 and extends the entire width
of fabric layer 41 across the entire width of planar body 21 from
first lateral edge 27 to second lateral edge 29. External adhesive
layer 55 includes an outer surface, which is opposite fabric layer
41, to which release member 59 may be removably mated. According to
one or more embodiments of the present invention, external adhesive
layer 55 can be used to secure membrane composite 13 to a roof
surface or adjoining membrane. Fabric layer 41 advantageously
serves to provide impact strength and/or resistance to the
composite, which will facilitate certain applications of the
membrane composite, such as re-skinning procedures.
UV-Curable Hot-Melt Pressure-Sensitive Adhesive
[0019] In one or more embodiments, the pressure-sensitive adhesive
layer (e.g. layer 31 in FIG. 1 and FIG. 2) is a cured
pressure-sensitive adhesive. In sub-embodiments thereof, this cured
pressure-sensitive adhesive layer is formed from a curable hot-melt
adhesive. In other words, and as will be described in greater
detail below, an uncured adhesive composition is applied to the
membrane as a hot-melt composition (i.e. the composition is heated
and applied as a flowable composition in the absence or appreciable
absence of solvent), and then the composition is subsequently
crosslinked (i.e. cured) to form the cured pressure-sensitive
layer.
[0020] In one or more embodiments, the cured pressure-sensitive
adhesive layer may be an acrylic-based hot-melt adhesive. In one or
more embodiments, the adhesive is a polyacrylate such as a
polyacrylate elastomer. In one or more embodiments, useful
polyacrylates include one or more units defined by the formula:
##STR00001##
where each R.sup.1 is individually hydrogen or a hydrocarbyl group
and each R.sup.2 is individually a hydrocarbyl group. In the case
of a homopolymer, each R.sup.1 and R.sup.2, respectively,
throughout the polymer are same in each unit. In the case of a
copolymer, at least two different R.sup.1 and/or two different
R.sup.2 are present in the polymer chain.
[0021] In one or more embodiments, hydrocarbyl groups include, for
example, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl,
cycloalkenyl, substituted cycloalkenyl, aryl, substituted aryl,
aralkyl, alkaryl, allyl, and alkynyl groups, with each group
containing in the range of from 1 carbon atom, or the appropriate
minimum number of carbon atoms to form the group, up to about 20
carbon atoms. These hydrocarbyl groups may contain heteroatoms
including, but not limited to, nitrogen, oxygen, boron, silicon,
sulfur, and phosphorus atoms. In particular embodiments, each
R.sup.2 is an alkyl group having at least 4 carbon atoms. In
particular embodiments, R.sup.1 is hydrogen and R.sup.2 is selected
from the group consisting of butyl, 2-ethylhexyl, and mixtures
thereof.
[0022] In one or more embodiments, the polyacrylate elastomers that
are useful as adhesives in the practice of this invention may be
characterized by a glass transition temperature (Tg) of less than
0.degree. C., in other embodiments less than -20.degree. C., in
other embodiments less than -30.degree. C. In these or other
embodiments, useful polyacrylates may be characterized by a Tg of
from about -70 to about 0.degree. C., in other embodiments from
about -50 to about -10.degree. C., and in other embodiments from
about -40 to about -20.degree. C.
[0023] In one or more embodiments, the polyacrylate elastomers that
are useful as adhesives in the practice of this invention may be
characterized by a number average molecular weight of from about 90
to about 800 kg/mole, in other embodiments from about 100 to about
350 kg/mole, in other embodiments from about 100 to about 700
kg/mole, in other embodiments from about 150 to about 270 kg/mole,
in other embodiments from about 120 to about 600 kg/mole, and in
other embodiments from about 180 to about 250 kg/mole.
[0024] In one or more embodiments, the polyacrylate elastomers that
are useful as adhesives in the practice of this invention may be
characterized by a Brookfield viscosity at 150.degree. C. of from
about 10,000 to about 200,000 cps, in other embodiments from about
30,000 to about 60,000 cps, in other embodiments from about 30,000
to about 170,000 cps, in other embodiments from about 25,000 to
about 150,000 cps, in other embodiments from about 30,000 to about
60,000 cps, and in other embodiments from about 40,000 to about
50,000 cps.
[0025] Specific examples of polyacrylate elastomers that are useful
as adhesives in the practice of the present invention include
poly(butylacrylate), and poly(2-ethylhexylacrylate). These
polyacrylate elastomers may be formulated with photoinitiators,
solvents, plasticizers, and resins such as natural and hydrocarbon
resins. The skilled person can readily formulate a desirable
adhesive composition. Useful adhesive compositions are disclosed,
for example, in U.S. Pat. Nos. 6,720,399, 6,753,079, 6,831,114,
6,881,442, and 6,887,917, which are incorporated herein by
reference.
[0026] In other embodiments, the polyacrylate elastomers may
include polymerized units that serve as photoinitiators. These
units may derive from copolymerizable photoinitiators including
acetophenone or benzophenone derivatives. These polyacrylate
elastomers and the adhesive compositions formed therefrom are known
as disclosed in U.S. Pat. Nos. 7,304,119 and 7,358,319, which are
incorporated herein by reference.
[0027] Useful adhesive compositions are commercially available in
the art. For example, useful adhesives include those available
under the tradename acResin (BASF), those available under the
tradename AroCure (Ashland Chemical), and NovaMeltRC (NovaMelt). In
one or more embodiments, these hot-melt adhesives may be cured
(i.e., crosslinked) by UV light.
[0028] In one or more embodiments, the hot-melt adhesive is at
least partially cured after being applied to the membrane, as will
be discussed in greater detail below. In one or more embodiments,
the adhesive is cured to an extent that it is not thermally
processable in the form it was prior to cure. In these or other
embodiments, the cured adhesive is characterized by a cross-linked
infinite polymer network. While at least partially cured, the
adhesive layer of one or more embodiments is essentially free of
curative residue such as sulfur or sulfur crosslinks and/or
phenolic compounds or phenolic-residue crosslinks.
[0029] As indicated above, the pressure-sensitive adhesive, in its
cured stated, provides sufficient tack to allow the membrane
composites of this invention to be used in roofing systems that
meet industry standards for wind uplift resistance. In one or more
embodiments, this tack may be quantified based upon the peel
strength when adhered to another membrane in accordance with ASTM
D-1876-08. In one or more embodiments, the cured pressure-sensitive
adhesive of the present invention is characterized by a peel
strength, according to ASTM D-1876-08, of at least 1.8 lbf/in, in
other embodiments at least 3.6 lbf/in, in other embodiments at
least 8.0 lbf/in, in other embodiments at least 15 lbf/in, and in
other embodiments at least 20 lbf/in.
[0030] Similarly, the tack of the pressure-sensitive adhesive, in
its cured state, may be quantified based upon the peel strength
when adhered to a construction board (e.g. insulation board) having
a kraft paper facer in accordance with ASTM D-903-98 (2010). In one
or more embodiments, the cured pressure-sensitive adhesive of the
present invention is characterized by a peel strength, according to
ASTM D-903-98 (2010) using an insulation board with kraft paper
facer, of at least 1.5 lbf/in, in other embodiments at least 2.0
lbf/in, in other embodiments at least 2.5 lbf/in, in other
embodiments at least 3.0 lbf/in, and in other embodiments at least
3.5 lbf/in.
Release Member
[0031] In one or more embodiments, the release member (e.g. release
member 71 and 57), which may also be referred to as a release
member or release paper, may include a polymeric film or extrudate,
or in other embodiments it may include a cellulosic substrate. In
one or more embodiments, the polymeric film and/or cellulosic
substrate can carry a coating or layer that allows the polymeric
film and/or cellulosic substrate to be readily removed from the
adhesive layer after attachment. This polymeric film or extrudate
may include a single polymeric layer or may include two or more
polymeric layers laminated or coextruded to one another.
[0032] Suitable materials for forming a release member that is a
polymeric film or extrudate include polypropylene, polyester,
high-density polyethylene, medium-density polyethylene, low-density
polyethylene, polystyrene or high-impact polystyrene. The coating
or layer applied to the film and/or cellulosic substrate may
include a silicon-containing or fluorine-containing coating. For
example, a silicone oil or polysiloxane may be applied as a
coating. In other embodiments, hydrocarbon waxes may be applied as
a coating. As the skilled person will appreciate, the coating,
which may be referred to as a release coating, can be applied to
both planar surfaces of the film and/or cellulosic substrate. In
other embodiments, the release coating need only be applied to the
planar surface of the film and/or cellulosic substrate that is
ultimately removably mated with the adhesive layer.
[0033] In one or more embodiments, the release member is
characterized by a thickness of from about 15 to about 80 .mu.m, in
other embodiments from about 18 to about 75 .mu.m, and in other
embodiments from about 20 to about 50 .mu.m.
Thickness of Adhesive Layer
[0034] In one or more embodiments, the thickness of the
pressure-sensitive adhesive layer (e.g. layer 31) may be at least
15 .mu.m, in other embodiments at least 30 .mu.m, in other
embodiments at least 45 .mu.m, and in other embodiments at least 60
.mu.m. In these or other embodiments, the thickness of the
pressure-sensitive adhesive layer may be at most 1000 .mu.m, in
other embodiments at most 600 .mu.m, in other embodiments at most
300 .mu.m, in other embodiments at most 150 .mu.m, and in other
embodiments at most 75 .mu.m. In one or more embodiments, the
thickness of the pressure-sensitive adhesive layer may be from
about 15 .mu.m to about 600 .mu.m, in other embodiments from about
15 .mu.m to about 1000 .mu.m, in other embodiments from about 30
.mu.m to about 300 .mu.m, and in other embodiments from about 45
.mu.m to about 150 .mu.m.
Membrane Panel
[0035] In one or more embodiments, the membrane, which may be
referred to as a panel (e.g. panel 21) may be a thermoset material.
In other embodiments the membrane may be a thermoformable material.
In one or more embodiments, the membrane may be EPDM based. In
other embodiments, the membrane may be TPO based. In these or other
embodiments, the membrane may be flexible and capable of being
rolled up for shipment. In these or other embodiments, the membrane
may include fiber reinforcement, such as a scrim. In one or more
embodiments, the membrane includes EPDM membranes including those
that meet the specifications of the ASTM D-4637. In other
embodiments, the membrane includes thermoplastic membranes
including those that meet the specifications of ASTM D-6878-03.
Still other membranes may include PVC, TPV, CSPE, and asphalt-based
membranes.
[0036] In one or more embodiments, the roofing membrane panels are
characterized by conventional dimensions. For example, in one or
more embodiments, the membrane panels may have a thickness of from
about 500 .mu.m to about 3 mm, in other embodiments from about
1,000 .mu.m to about 2.5 mm, and in other embodiments from about
1,500 .mu.m to about 2 mm. In these or other embodiments, the
membrane panels of the present invention are characterized by a
width of about 1 m to about 20 m, in other embodiments from about 2
m to about 18 m, and in other embodiments from about 3 m to about
15 m.
Fabric Backing
[0037] In one or more embodiments, the fabric backing (e.g. fabric
backing 41) may include a synthetic fabric including glass or
polymeric fibers or filaments. In particular embodiments, the
fabric backing is a fleece, such as a napped fleece. Fleece
backings of the type that are useful as fabric backings for roofing
membranes are generally known in the art as described in U.S. Pat.
Nos. 4,996,812, 5,422,179, 5,981,030, and 6,502,360 which are
incorporated herein by reference. In particular embodiments, the
fabric backing is fleece prepared from polyester filaments such as
those prepared from polyethylene terephthalate. In one or more
embodiments, the fabric backing is a continuous filament polyester,
needle punched, nonwoven fabric. In other embodiments, the fabric
backing is a scrim reinforced nonwoven polyester mat. In yet other
embodiments, the fabric backing is a glass fiber mat.
[0038] In one or more embodiments, where the fabric backing is a
glass fiber mat, the fabric may be characterized by a basis weight
of at least 50, in other embodiments at least 60, and in other
embodiments at least 70 g/m.sup.2. In these or other embodiments,
the glass fiber mat may be characterized by a basis weight of at
most 150, in other embodiments at most 130, and in other
embodiments at most 100 g/m.sup.2. In one or more embodiments, the
glass fiber mat may be characterized by a basis weight of from
about 50 to about 150 g/m.sup.2, in other embodiments from about 60
to about 130 g/m.sup.2, and in other embodiments from about 70 to
about 110 g/m.sup.2.
[0039] In one or more embodiments, where the fabric backing is a
glass fiber mat, the glass mat may be characterized by a thickness
of at least 0.5 mm, in other embodiments at least 0.7 mm, and in
other embodiments at least 1.0 mm. In these or other embodiments,
the glass mat may be characterized by a thickness of at most 2.0
mm, in other embodiments at most 1.5 mm, and in other embodiments
at most 1.2 mm. In one or more embodiments, the glass mat may be
characterized by a thickness of from about 0.5 to about 2.0 mm, in
other embodiments from about 0.7 to about 1.5 mm, and in other
embodiments from about 1.0 to about 1.2 mm.
[0040] In one or more embodiments, where the fabric backing is a
polyester fleece, the fabric may be characterized by a basis weight
of at least 70, in other embodiments at least 85, and in other
embodiments at least 100 g/m.sup.2. In these or other embodiments,
the polyester fleece may be characterized by a basis weight of at
most 400, in other embodiments at most 300, and in other
embodiments at most 280 g/m.sup.2. In one or more embodiments, the
polyester fleece may be characterized by a basis weight of from
about 70 to about 400 g/m.sup.2, in other embodiments from about 85
to about 300 g/m.sup.2, and in other embodiments from about 100 to
about 280 g/m.sup.2.
[0041] In one or more embodiments, where the fabric backing is a
polyester fleece, the glass mat may be characterized by a thickness
of at least 0.5 mm, in other embodiments at least 0.7 mm, and in
other embodiments at least 1.0 mm. In these or other embodiments,
the polyester fleece may be characterized by a thickness of at most
4.0 mm, in other embodiments at most 2.0 mm, and in other
embodiments at most 1.5 mm. In one or more embodiments, the
polyester fleece may be characterized by a thickness of from about
0.5 to about 4.0 mm, in other embodiments from about 0.7 to about
2.0 mm, and in other embodiments from about 1.0 to about 1.5
mm.
Preparation of Membrane Composite
[0042] The membrane panels employed in the membrane composites of
the present invention may be prepared by conventional techniques.
For example, thermoplastic membrane panels may be formed by the
extrusion of thermoplastic compositions into one or more layers
that can be laminated into a membrane panel. Thermoset membranes
can be formed using known calendering and curing techniques.
Alternatively, thermoset membranes can be made by continuous
process such as those disclosed in WO 2013/142562, which is
incorporated herein by reference.
[0043] Once the membrane is formed, the curable hot-melt adhesive
can be extruded onto the membrane by using known apparatus such as
adhesive coaters. The adhesive can then subsequently be cured by
using, for example, UV radiation. Once the adhesive has been
sufficiently cured (e.g. by exposure to UV curing), a fabric
backing can be applied to the cured coating, and then the composite
can be wound into a roll for storage and shipment. Advantageously,
where the membrane panel is made by using continuous techniques,
the process can be supplemented with continuous techniques for
applying and curing the adhesive coatings according to embodiments
of the present invention to thereby prepare usable membrane
composites within a single continuous process.
[0044] As generally shown in FIG. 5, process 230 for preparing a
composite membrane according to the present invention generally
begins with a step of heating 232, wherein a pressure-sensitive
adhesive is heated to a sufficient temperature to allow the
adhesive to be applied as a coating within a coating step 234.
Within coating step 234, the adhesive is applied to the membrane to
form a coating layer. Following formation of the coating, the
coating is subjected to a UV-curing step 236 where sufficient UV
energy is applied to the coating to thereby effect a desirable
curing or crosslinking of the adhesive. Once the adhesive has been
sufficiently cured by exposure to UV curing step 236, a fabric
backing can be applied to the cured coating in an application step
238. Following application of the fabric, the composite can be
wound into a roll at winding step 240.
[0045] In one or more embodiments, heating step 232 heats the
adhesive to a temperature of from about 120 to about 160.degree.
C., in other embodiments from about 125 to about 155.degree. C.,
and in other embodiments from about 130 to about 150.degree. C.
[0046] In one or more embodiments, adhesive step 234 applies an
adhesive to the surface of a membrane to form an adhesive layer of
adhesive that has a thickness of at least 51 .mu.m (2 mil), in
other embodiments at least 102 .mu.m (4 mil), in other embodiments
at least 127 .mu.m (5 mil), and in other embodiments at least 152
.mu.m (6 mil). In one or more embodiments, adhesive step 234
applies an adhesive to the surface of a membrane to form a adhesive
layer of adhesive that has a thickness of from about 51 to about
381 .mu.m (about 2 to about 15 mil), in other embodiments from
about 102 to about 305 .mu.m (about 4 to about 12 mil), and in
other embodiments from about 127 to about 254 .mu.m (about 5 to
about 10 mil). In one or more embodiments, the adhesive has a
uniform thickness such that the thickness of the adhesive at any
given point on the surface of the membrane does not vary by more
than 51 .mu.m (2 mil), in other embodiments by more than 38 .mu.m
(1.5 mil), and in other embodiments by more than 25 .mu.m (1
mil).
[0047] In one or more embodiments, UV curing step 236 subjects the
adhesive to a UV dosage of from about 30 to about 380
millijoule/cm.sup.2, in other embodiments from about 35 to about
300 millijoule/cm.sup.2, in other embodiments from about 40 to
about 280 millijoule/cm.sup.2, in other embodiments from about 45
to about 240 millijoule/cm.sup.2, and in other embodiments from
about 48 to about 235 millijoule/cm.sup.2. It has advantageously
been discovered that the required dosage of energy can be exceeded
without having a deleterious impact on the adhesives of the present
invention. For example, up to ten times, in other embodiments up to
five times, and in other embodiments up to three times the required
dosage can be applied to the adhesive composition without having a
deleterious impact on the adhesive composition and/or its use in
the present invention.
[0048] In one or more embodiments, UV curing step 236 subjects the
adhesive to a UV intensity, which may also be referred to as UV
irradiance, of at least 150 milliWatts/cm.sup.2, in other
embodiments at least 200, and in other embodiments at least 250
milliWatts/cm.sup.2. In these or other embodiments, UV curing step
36 subjects the adhesive to a UV intensity of from about 150 to
about 500 milliWatts/cm.sup.2, in other embodiments from about 200
to about 400 milliWatts/cm.sup.2, and in other embodiments from
about 250 to about 350 milliWatts/cm.sup.2. It has advantageously
been discovered that the ability to appropriately cure the adhesive
compositions of the present invention, and thereby provide a useful
pressure-sensitive adhesive for the roofing applications disclosed
herein, critically relies on the UV intensity applied to the
adhesive. It is believed that the thickness of the adhesives (and
therefore the thickness of the pressure-sensitive adhesive layer)
employed in the present invention necessitates the application of
greater UV intensity.
[0049] In one or more embodiments, the energy supplied to the
adhesive layer within UV radiation step 236 is in the form of UV-C
electromagnetic radiation, which can be characterized by a wave
length of from about 250 to about 260 nm. In one or more
embodiments, the UV dosage applied during UV curing step 236 is
regulated based upon a UV measuring and control system that
operates in conjunction with UV curing step 236. According to this
system, UV measurements are taken proximate to the surface of the
adhesive layer using known equipment such as a UV radiometer. The
data from these measurements can be automatically inputted into a
central processing system that can process the information relative
to desired dosage and/or cure states and automatically send signal
to various variable-control systems that can manipulate one or more
process parameters. For example, the power supplied to the UV lamps
and/or the height at which the UV lamps are positioned above the
adhesive layer can be manipulated automatically based upon
electronic signal from the central processing unit. In other words,
the UV intensity, and therefore the UV dosage, can be adjusted in
real time during the manufacturing process.
[0050] In one or more embodiments, an exemplary process for
preparing the membrane composites of the present invention can be
described with reference to FIG. 6. Continuous process 250 includes
a heating step 252 where UV-curable hot-melt adhesive 251 is heated
to a desired temperature within a heated tank 253. Adhesive 251 is
fed into an extrusion device, such as a coater 255, which may
include a pump, such as a gear pump 257, and a slot die 259. Within
coating step 254, coater 255 extrudes adhesive 251, which is in its
molten, liquid or flowable state, and deposits a coating layer 261
of adhesive 251 onto a planar surface 263 of membrane 265.
[0051] As shown in FIG. 6, coating step 254 can include a
roll-coating operation, where adhesive 251 is applied to membrane
265 while membrane 265 is at least partially wound around a coating
mandrel 267. Membrane 265 carrying coating layer 261 is fed to a
crosslinking step 256, where coating layer 261 of adhesive 251 is
subjected to a desired dosage of UV radiation 269, which may be
supplied by one or more UV lamps 271. UV lamps 271 may include, for
example, mercury-type UV lamps or LED UV lamps. As the skilled
person appreciates, the desired dosage of UV energy can be supplied
to coating 261 by adjusting the UV intensity and exposure time. The
intensity can be manipulated by the power supplied to the
respective lamps and the height (H) that the lamps are placed above
the surface of coating 261 of adhesive 251. Exposure time can be
manipulated based upon the line speed (i.e., the speed at which
membrane 265 carrying coating layer 261 is passed through UV curing
step 256).
[0052] Following UV curing step 256, fabric 273 may be applied to
upper surface 275 of coating layer 261 within fabric application
step 258. As shown in FIG. 6, fabric 273 may be supplied from a
mandrel 277 and mated to upper surface 275 through pressure
supplied by nip rolls 279. After application of fabric 273, the
composite product may be wound within winding step 260 to provide
wound rolls 281 of composite products 283.
Installation of Membrane Composite
[0053] In one or more embodiments, the membrane composites of the
present invention can be adhesively secured to a roof system (i.e.
secured to an underlying roof substrate) by employing techniques
well known in the art of securing fabric-backed roofing membranes.
For example, a liquid-based adhesive can be applied to the roof
surface and then the membrane composite can be unrolled onto the
adhesive to contact the fabric backing to the adhesive. Various
liquid-based adhesives can be employed including polyurethane,
one-part and two-part adhesives (which are often foaming
adhesives), as well as those bonding adhesives based upon
polychloroprenes and neoprenes. Other adhesive systems include
solvent-free bonding adhesive such as those polymeric systems that
rely upon silicon functionalities for crosslinking. Exemplary
solvent-free bonding systems include those described in U.S. Publ.
No. 2016/0340905, which is incorporated herein by reference. Using
conventional techniques, adjacent membranes are typically
overlapped, and a lap seam is formed between overlapping membranes.
In the case of thermoplastic membranes, the lap seam can be formed
by heat welding. Alternatively, especially in the case of EPDM
membranes, a lap seam can be formed by using a solid tape or liquid
adhesive (e.g. butyl-based adhesive). In yet other embodiments, as
suggested with respect to FIG. 2, the adhesives employed in the
present invention for securing the fabric backing to the membrane
can also be used in securing a seam between adjacent, overlapping
membranes. In other embodiments, such as those described with
reference to FIG. 3, the outer adhesive layer can be used, after
exposing the layer by removal of the release liner, to secure the
membrane composite to the roof deck and/or to adjacent membranes by
employing standard peel-and-stick techniques.
Roof System
[0054] A roof system according to embodiments of the present
invention can be described with reference to FIG. 4, which shows
roof system 101 including membrane composite 111, which includes
planar body 113 and fabric backing 115 secured to planar body 113
through pressure-sensitive adhesive layer 117.
[0055] Various modifications and alterations that do not depart
from the scope and spirit of this invention will become apparent to
those skilled in the art. This invention is not to be duly limited
to the illustrative embodiments set forth herein.
* * * * *