U.S. patent application number 17/531951 was filed with the patent office on 2022-03-17 for thermoplastic roofing membranes for fully-adhered roofing systems.
The applicant listed for this patent is Firestone Building Products Company, LLC. Invention is credited to Donna TIPPMANN, Hao WANG.
Application Number | 20220080712 17/531951 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-17 |
United States Patent
Application |
20220080712 |
Kind Code |
A1 |
WANG; Hao ; et al. |
March 17, 2022 |
THERMOPLASTIC ROOFING MEMBRANES FOR FULLY-ADHERED ROOFING
SYSTEMS
Abstract
A thermoplastic membrane comprising at least one layer including
a thermoplastic polyolefin and a functionalized polyolefin
copolymer.
Inventors: |
WANG; Hao; (Carmel, IN)
; TIPPMANN; Donna; (Fishers, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Firestone Building Products Company, LLC |
Nashville |
TN |
US |
|
|
Appl. No.: |
17/531951 |
Filed: |
November 22, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15327867 |
Jan 20, 2017 |
11179924 |
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PCT/US2015/041707 |
Jul 23, 2015 |
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17531951 |
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62028010 |
Jul 23, 2014 |
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International
Class: |
B32B 27/32 20060101
B32B027/32; B32B 27/08 20060101 B32B027/08; B32B 27/12 20060101
B32B027/12; B32B 27/20 20060101 B32B027/20; E04D 5/06 20060101
E04D005/06; E04D 5/10 20060101 E04D005/10; C08L 53/00 20060101
C08L053/00; C08K 3/26 20060101 C08K003/26; C08L 23/10 20060101
C08L023/10; B32B 5/02 20060101 B32B005/02; C08L 51/06 20060101
C08L051/06; C08L 23/16 20060101 C08L023/16; C08L 23/08 20060101
C08L023/08; C08L 23/14 20060101 C08L023/14 |
Claims
1. A multi-layered thermoplastic membrane including: (i) a first
layer including first and second coextrudate layers, where the
first coextrudate layer includes a thermoplastic polyolefin and
from 15 to 50 weight percent magnesium hydroxide based on the
entire weight of the first coextrudate layer, and is devoid of a
functionalized polyolefin, and where the second coextrudate layer
includes a thermoplastic polyolefin, from 33 to 80 weight percent
mineral filler based on the entire weight of the second coextrudate
layer, and from about 1 to about 20 weight percent of a
functionalized polyolefin copolymer based upon the entire weight of
the second coextrudate layer, and (ii) a second layer including a
thermoplastic polyolefin, from 33 to 80 weight percent mineral
filler based on the entire weight of the second layer, and from
about 1 to about 20 weight percent of a functionalized polyolefin
copolymer based upon the entire weight of the second layer, said
second layer including a planar surface forming an exterior surface
of the multi-layered thermoplastic membrane.
2. The thermoplastic membrane of claim 1, wherein the second layer
includes from about 2 to about 15 weight percent of the
functionalized polyolefin copolymer based upon the entire weight of
the second layer.
3. The thermoplastic membrane of claim 1, wherein the second layer
includes from about 3 to about 10 weight percent of the
functionalized polyolefin copolymer based upon the entire weight of
the second layer.
4. The thermoplastic membrane of claim 1, where the first
coextrudate layer is devoid of clay.
5. The thermoplastic membrane of claim 1, where the thermoplastic
polyolefin is a reactor copolymer of ethylene and propylene.
6. The thermoplastic membrane of claim 1, where the functionalized
polyolefin copolymer is a maleated copolymer of ethylene and an
.alpha.-olefin.
7. The thermoplastic membrane of claim 1, where the mineral filler
is calcium carbonate.
8. The thermoplastic membrane of claim 1, where the mineral filler
is clay.
9. A roof system comprising: (i) a roof substrate; and (ii) a
thermoplastic membrane including at least one layer including a
thermoplastic polyolefin and a functionalized polyolefin copolymer,
where the membrane is adhered to the roof substrate and wherein
said at least one layer further includes from 33 to 80 weight
percent of a mineral filler based on the entire weight of the at
least one layer.
10. The roof system of claim 9, where the thermoplastic membrane is
characterized, prior to being adhered to the substrate, by a
stiffness represented by a flexural modulus of less than 90 MPa, or
by a Taber stiffness of less than 15, or by a shore D hardness of
less than 40, or by a combination thereof.
11. The roof system of claim 9, where at least 50% of at least one
planar surface of the membrane is adhered to the substrate.
Description
[0001] This application is a Divisional Application of U.S.
application Ser. No. 15/327,867 filed on Jan. 20, 2017, which is a
National-Stage Application of PCT/US2015/041707 filed on Jul. 23,
2015, and which claims the benefit of U.S. Provisional Application
No. 62/028,010 filed on Jul. 23, 2014, which are incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention provide thermoplastic
roofing membranes that are useful for fully-adhered roofing
systems; the overall membranes are characterized by an
advantageously low flexural modulus.
BACKGROUND OF THE INVENTION
[0003] Thermoplastic roofing membranes, especially those membranes
engineered to cover flat or low-sloped roofs, are known in the art.
In fact, many of these membranes are engineered to meet the
industry standards defined in ASTM D 790. Among the performance
requirements provided in this industry standard, thermoplastic
roofing membranes must meet threshold requirements for tensile
strength and tear strength. Tensile strength is an indicator of
seam strength, and the seam strength must withstand wind uplift
forces. Tear strength is primarily important from the standpoint of
fastener pull through. That is, where the membrane is mechanically
attached to the roof surface, the membrane must be able to
withstand threshold wind uplift forces without tear at the location
of the fastener.
[0004] Many commercially-available thermoplastic roofing membranes
include fabric-reinforced thermoplastic sheets. These membranes are
fabricated by sandwiching a reinforcing fabric between two extruded
thermoplastic sheets to provide a laminated structure. The
thermoplastic extruded sheets, which can be the same or different,
often include ethylene-propylene reactor copolymers (e.g. CA10A
available from Lyondellbasell), together with various additives,
such as inert filler, anti-weathering additives, and flame
retardants. As the skilled person appreciates, the type and amount
of additives employed, such as the filler, can impact the
mechanical properties of the membrane including tensile and tear
strength.
[0005] While industry standards for thermoplastic roofing membranes
are designed with an eye toward mechanically-attached thermoplastic
roofing systems, fully-adhered systems also exist. In fact,
fully-adhered systems are often viewed as superior roof systems. As
the skilled person appreciates, a fully-adhered system is installed
by using an adhesive that attaches the membrane to the roof
surface, where the adhesive substantially contacts all of the
membrane surface adjacent to the roof deck. In practice, liquid
bond adhesives or pressure-sensitive adhesives that are factory
applied to the membrane are often used.
[0006] A problem encountered when installing fully-adhered
thermoplastic roofing sheets relates to the stiffness of the
roofing sheet. As the skilled person appreciates, the integrity of
a fully-adhered system can hinge on the degree to which the overall
surface of the membrane is adhered. Where areas or pockets exist
that are not adhered, the system can fail wind uplift tests. This
is particularly true where the membrane is not fully adhered over
uneven surfaces in the roof, such as fastening plates that are
often used to secure underlying insulation boards. The skilled
person understands that the stiffness of the sheet creates problems
when attempting to evenly apply the sheet over the roof surface,
especially uneven substrates. A goal often sought is the ability to
view the underlying contours of the roof surface though the
membrane, which is indicative of complete adhesion to the roof.
Where the membrane is too stiff, the membrane will not contour to
the underlying surface. A term often used in the art is
telegraphing, which refers to the ability of the sheet to contour
to the substrate and thereby allow the presence of the substrate to
be noticed with the sheet in place.
SUMMARY OF THE INVENTION
[0007] One or more embodiments of the present invention provide a
thermoplastic membrane comprising at least one layer including a
thermoplastic polyolefin and a functionalized polyolefin
copolymer.
[0008] Still other embodiments of the present invention provide a
multi-layered thermoplastic membrane comprising a first layer
including a thermoplastic polyolefin and magnesium hydroxide and a
second layer including a thermoplastic polyolefin, calcium
carbonate or clay, and a functionalized polyolefin copolymer.
[0009] Yet other embodiments of the present invention provide a
roof system comprising a roof substrate and a membrane including at
least one layer including a thermoplastic polyolefin and a
functionalized polyolefin copolymer, where the membrane is fully
adhered to the roof substrate
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a single-extrudate membrane
according to embodiments of the present invention.
[0011] FIG. 2 is a perspective view of a laminate membrane
according to embodiments of the present invention.
[0012] FIG. 3 is a perspective view of laminate membrane according
to embodiments of the present invention.
[0013] FIG. 4 is a cross-sectional view of a fully-adhered roofing
system according to embodiments of the present invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0014] Embodiments of the present invention are based, at least in
part, on the discovery of thermoplastic roofing membranes that can
advantageously be used for fully-adhered roofing systems. These
membranes are characterized by a relatively low stiffness, which
allows the membranes to be installed using fully-adhered attachment
techniques while overcoming installation problems associated with
stiffness. In one or more embodiments, at least one layer of the
membranes of the present invention includes a functionalized
polyolefin copolymer. While the relatively low stiffness (as may be
indicated by flexural modulus) carries with it a corresponding loss
in certain mechanical properties, it has unexpectedly been
discovered that the overall balance of properties is sufficient to
provide technologically useful fully-adhered systems. For example,
while low flexural modulus may be associated with a corresponding
loss in fastener pull-through strength or resistance, the fact that
the membrane systems are fully adhered diminishes the deleterious
impact caused by this loss in property. Moreover, it has been
advantageously discovered that the flexibility of the membrane can
be maintained at relatively high filler loadings to provide
membranes that are useful for constructing fully-adhered roofing
systems. Accordingly, embodiments of the invention are directed
toward fully-adhered roof systems that include membranes having
relatively low stiffness as described herein.
Membrane Construction
[0015] Membranes according to one or more embodiments of the
present invention can be described with reference to FIG. 1. In
this embodiment, the membrane includes planar body 11, which also
may be referred to as sheet 11 or panel 11. In this embodiment,
panel 11 is a planar body that consists of a single extrudate. In
one or more embodiments, planar body 11 may be compositionally
homogeneous or, in other embodiments, planar body 11 may include
one or more compositionally distinct layers 13 and 15. For example,
compositionally distinct layers 13 and 15 may be formed through
coextrusion techniques, and reference may therefore be made to
coextruded layers 13 and 15, or first coextruded layer 13 and
second coextruded layer 15. According to aspects of the present
invention, body 11 or layers 13 and/or 15 include a functionalized
polyolefin copolymer.
[0016] In other embodiments, the membranes of one or more
embodiments of the present invention may include two or more
laminated layers. For example, as shown in FIG. 2, membrane 21 may
include first layer 23 and second layer 25, which are laminated to
one another, optionally with a reinforcing scrim 27 disposed
between laminated layers 23 and 25. According to aspects of the
present invention, at least one of layers 23 and 25 include a
functionalized polyolefin copolymer. First layer 23 and second
layer 25 may be compositionally similar with respect to one
another. Or, in other embodiments, the layers may be
compositionally distinct. Additionally, layers 23 and 25 may,
within themselves, be compositionally homogeneous or, in other
embodiments, they may be nonhomogeneous. For example, either first
layer 23, second layer 25, or both layers 23 and 25, may include
compositionally distinct coextruded layers. In this respect, U.S.
Publ. Nos. 2009/0137168, 2009/0181216, 2009/0269565, 2007/0193167,
and 2007/0194482 are incorporated herein by reference. As shown in
FIG. 3, first layer 23 may include compositionally distinct
coextruded layers 31 and 33, and second layer 25 may include
compositionally distinct coextruded layers 35 and 37. According to
aspects of the present invention, at least one of coextruded layers
31 and 33 or at least one of coextruded layers 35 and 37 include a
functionalized polyolefin copolymer.
[0017] As will be discussed in greater detail below, one or more
layers of the membranes of this invention include a functionalized
polyolefin copolymer. With reference to FIG. 3, these one or more
layers may include upper middle layer 33, as well as lower middle
layer 35 and bottom layer 37. In these or other embodiments, top
layer 31 may also include the functionalized polyolefin copolymer.
In certain embodiments, top layer 31 includes a propylene-based
polymer that is distinct from a functionalized polyolefin
copolymer, such as a propylene-based olefinic polymer as will be
described in greater detail below. In these or other embodiments,
top layer 31 is devoid of a functionalized polyolefin copolymer.
Additionally, in certain embodiments, bottom layer 37 may include a
functionalized thermoplastic resin. In one or more embodiments, top
layer 31 includes flame retardants and other weathering additives
that may provide sufficient environmental protection to the
polymers, while at least one of layers 33, 35, and 37 may include
fillers such as mineral fillers.
Membrane Characteristics
[0018] As discussed above, the membranes employed in the practice
of this invention are advantageously characterized by a relatively
low stiffness. In one or more embodiments, the low stiffness may be
represented by a relatively low flexural modulus, as determined by
ASTM D790. For example, the membranes of one or more embodiments of
this invention may have a flexural modulus, according to ASTM D790,
of less than 90 MPa, in other embodiments less than 80 MPa, in
other embodiments less than 70 MPa, in other embodiments less than
60 MPa, in other embodiments less than 50 MPa, in other embodiments
less than 40 MPa, and in other embodiments less than 30 MPa. In
these or other embodiments, the membranes may be characterized by a
flexural modulus of from about 5 to about 90 MPa, in other
embodiments from about 10 to about 80 MPa, and in other embodiments
from about 20 to about 70 MPa.
[0019] In one or more embodiments, the membranes employed in the
practice of this invention are advantageously characterized by a
relatively Shore hardness (e.g. low Shore A or Shore D). In one or
more embodiments, the membranes may be characterized by a Shore D
hardness, as determined by ASTM D2240, of less than 40, in other
embodiments less than 30, and in other embodiments less than 20. In
these or other embodiments, the membranes may be characterized by a
hardness of from about 70 Shore A to about 40 Shore D, in other
embodiments from about 80 Shore A to about 30 Shore D, and in other
embodiments from about 90 Shore A to about 20 Shore D.
[0020] In these or other embodiments, the relatively low stiffness
of the membranes of this invention may be represented by a
relatively low Taber stiffness. As the skilled person appreciates,
Taber stiffness is an advantageous measurement for reinforced
membrane materials because the measurements can be taken on samples
that include a fabric reinforcement. The skilled person understands
that these Taber stiffness values can be obtained by employing a
Taber stiffness tester, such as a model 510-E Taber V-5 stiffness
tester. The skilled person understands that the results of the
Taber stiffness test are reported in stiffness units with lower
values representing membranes of lower stiffness. In one or more
embodiments, the membranes employed in practice of the present
invention may be characterized by a Taber stiffness of less than
15, in other embodiments less than 12, in other embodiments less
than 8, in other embodiments less than 6, and in other embodiments
less than 4. In these or other embodiments, the membranes may be
characterized by a stiffness of from about 1 to about 15, in other
embodiments from about 2 to about 10, and in other embodiments from
about 3 to about 6. In one or more embodiments, the Taber stiffness
values of the membranes of the present invention are at least 100%,
in other embodiments at least 120%, and in other embodiments at
least 150% lower than comparative membranes prepared using similar
compositions absent the functionalized polyolefin.
Membrane Composition
[0021] In one or more embodiments, the advantageously low flexural
modulus is attributable to the polymeric composition of one or more
layers of the membrane. Specifically, in one or more embodiments,
at least one layer of the multi-layered membranes of the present
invention includes a functionalized thermoplastic polyolefin. In
these or other embodiments, at least one layer, optionally the at
least one layer containing a functionalized polyolefin copolymer,
includes a relatively high loading of filler, as described in
greater detail below.
Base Polymer
[0022] The one or more layers of the thermoplastic membranes of the
present invention are prepared from thermoplastic polyolefins
(TPO). According to aspects of the present invention, the
functionalized polyolefin, and optionally the filler and other
constituents, are included within the TPO composition. In one or
more embodiments, the TPO forms a matrix in which the
functionalized polyolefin copolymer and other constituents of the
composition are dispersed. In one or more embodiments, the
functionalized polyolefin copolymer and/or other constituents may
be co-continuous with the TPO matrix, or in other embodiments, one
or more of the constituents (e.g. filler) may exist as discreet
phases within the TPO matrix.
[0023] Practice of one or more embodiments of the present invention
is not limited by the selection of the TPO. In one or more
embodiments, the conventional thermoplastic polymer may include an
olefinic reactor copolymer, which may also be referred to as
in-reactor copolymer. Reactor copolymers are generally known in the
art and may include blends of olefinic polymers that result from
the polymerization of ethylene and .alpha.-olefins (e.g.,
propylene) with sundry catalyst systems. In one or more
embodiments, these blends are made by in-reactor sequential
polymerization. Reactor copolymers useful in one or more
embodiments include those disclosed in U.S. Pat. No. 6,451,897,
which is incorporated therein by reference. Reactor copolymers,
which are also referred to as TPO resins, are commercially
available under the tradename HIFAX.TM. (Lyondellbassel); these
materials are believed to include in-reactor blends of
ethylene-propylene rubber and polypropylene or polypropylene
copolymers. Other useful thermoplastic olefins include those
available under the tradename T00G-00 (Ineos). In one or more
embodiments, the in-reactor copolymers may be physically blended
with other polyolefins. For example, in reactor copolymers may be
blended with linear low density polyethene.
[0024] In one or more embodiments, the thermoplastic polyolefins
may include propylene-based elastomer, optionally in combination
with a thermoplastic resin. In other words, the polymeric
composition of one or more layers may include a propylene-based
elastomer. In these or other embodiments, the polymeric composition
includes a blend of a propylene-based elastomer and a
propylene-based thermoplastic resin. In one or more embodiments,
both propylene-based elastomer and the propylene-based
thermoplastic resin have isotactic propylene sequences long enough
to crystallize. In this regard, U.S. Pat. No. 6,927,258, and U.S.
Publ. Nos. 2004/0198912 and 2010/0197844 are incorporated herein by
reference.
[0025] In one or more embodiments, the propylene-based elastomer is
propylene/alpha-olefin copolymer with semi-crystalline isotactic
propylene segments. The alpha-olefin content (e.g. polymerized
ethylene content) may range from about 5 to about 18%, or in other
embodiments from about 10 to about 15%.
[0026] In one or more embodiments, the propylene-based elastomer is
characterized by a melting point that is less than 110.degree. C.
and a heat of fusion of less than 75 J/g.
[0027] In one embodiment, the propylene based elastomers have a
glass transition temperature (Tg) in the range of about -25 to
-35.degree. C. The Tg as used herein is the temperature above which
a polymer becomes soft and pliable, and below which it becomes hard
and glassy. The propylene-based elastomers may have a MFR range
measured at 230.degree. C. of between about 0.5 to about 25, and a
melt temperature range of about 50 to 120.degree. C.
[0028] In one embodiment, the propylene-based elastomers have a
shore A hardness range of about 60 to about 90.
[0029] In those embodiments where the propylene-based elastomer is
blended with a propylene-based thermoplastic resin, the
propylene-based thermoplastic resin may include a crystalline
resin. In particular embodiments, the propylene-based thermoplastic
resin is characterized by a melting point that is greater than
110.degree. C. and a heat of fusion greater than 75 J/g. In one or
more embodiments, the propylene-based thermoplastic resin is
stereoregular polypropylene. In one or more embodiments, the weight
ratio of the propylene-based elastomer to the thermoplastic resin
within the blend may vary in the range of 1:99 to 95:5 by weight
and, in particular, in the range 2:98 to 70:30 by weight.
[0030] In one embodiment, the propylene-based elastomers have a
flexural modulus range of about 500 to about 6000 Psi, or in other
embodiments about 1500 to about 5000 psi.
Functionalized Polyolefin Copolymers
[0031] In one or more embodiments, the functionalized polyolefin
copolymer is a polyolefin copolymer that includes at least one
functional group. The functional group, which may also be referred
to as a functional substituent or functional moiety, includes a
hetero atom. In one or more embodiments, the functional group
includes a polar group. Examples of polar groups include hydroxy,
carbonyl, ether, ester halide, amine, imine, nitrile, oxirane
(e.g., epoxy ring) or isocyanate groups. Exemplary groups
containing a carbonyl moiety include carboxylic acid, anhydride,
ketone, acid halide, ester, amide, or imide groups, and derivatives
thereof. In one embodiment, the functional group includes a
succinic anhydride group, or the corresponding acid, which may
derive from a reaction (e.g., polymerization or grafting reaction)
with maleic anhydride, or a .beta.-alkyl substituted propanoic acid
group or derivative thereof. In one or more embodiments, the
functional group is pendant to the backbone of the hydrocarbon
polymer. In these or other embodiments, the functional group may
include an ester group. In specific embodiments, the ester group is
a glycidyl group, which is an ester of glycidol and a carboxylic
acid. A specific example is a glycidyl methacrylate group.
[0032] In one or more embodiments, the polyolefin copolymers to
which the functional group is attached (i.e., the backbone of the
functionalized polyolefin copolymer) is the copolymerization
product of two distinct olefin monomers. In one or more
embodiments, the backbone is a copolymer of ethylene and an
.alpha.-olefin such as, but not limited to, propylene, 1-butene,
1-hexene, 1-octene, 2-methyl-1-propene, 3-methyl-1-pentene,
4-methyl-1-pentene, 5-methyl-1-hexene, and mixtures thereof. In one
or more embodiments, these polyolefin copolymers may be referred to
as ethylene-based copolymers. In one or more embodiments, the
ethylene-based copolymers may include from about 0.1 to about 30,
in other embodiments from about 1 to about 20, and in other
embodiments from about 2 to about 15 weight percent polymeric units
deriving from the copolymerization of .alpha.-olefin (i.e., monomer
other than ethylene).
[0033] In other embodiments, the backbone is a copolymer of
propylene and ethylene or another .alpha.-olefin such as, but not
limited to, 1-butene, 1-hexene, 1-octene, 2-methyl-1-propene,
3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, and
mixtures thereof. In one or more embodiments, these polyolefin
copolymers may be referred to as propylene-based copolymers. In one
or more embodiments, the propylene-based copolymers may include
from about 0.1 to about 30, in other embodiments from about 1 to
about 20, and in other embodiments from about 2 to about 15 weight
percent polymeric units deriving from the copolymerization of
ethylene or another .alpha.-olefin (i.e., monomer other than
propylene).
[0034] In one or more embodiments, the functionalized polyolefin
copolymers include semi-crystalline polymers. In other embodiments,
the functionalized polyolefin copolymers include amorphous
polymers. In one or more embodiments, the functionalized polyolefin
copolymers may be characterized by a crystallinity of less than
20%, in other embodiments less than 10%, in other embodiments less
than 5%, and in other embodiments less than 1%. In certain
embodiments, the functionalized polyolefin copolymers are amorphous
and are therefore characterized by 0% crystallinity. Crystallinity
may be determined by dividing the heat of fusion of a sample by the
heat of fusion of a 100% crystalline polymer, which is assumed to
be 209 joules/gram for polypropylene or 350 joules/gram for
polyethylene. Heat of fusion can be determined by differential
scanning calorimetry. In these or other embodiments, the
functionalized polyolefin copolymers to be functionalized may be
characterized by having a heat of fusion of less than 80 J/g, in
other embodiments less than 40 J/g, in other embodiments less than
20 J/g, and in other embodiments less than 10 J/g, in other
embodiments less than 5 J/g.
[0035] In one or more embodiments, the functionalized polyolefin
copolymers may be characterized by a weight average molecular
weight (M.sub.w) of from about 100 kg/mole to about 2,000 kg/mole,
and in other embodiments from about 300 kg/mole to about 600
kg/mole. They may also characterized by a number-average molecular
weight (M.sub.n) of about 80 kg/mole to about 800 kg/mole, and in
other embodiments about 90 kg/mole to about 200 kg/mole. Molecular
weight may be determined by size exclusion chromatography (SEC) by
using a Waters 150 gel permeation chromatograph equipped with the
differential refractive index detector and calibrated using
polystyrene standards.
[0036] In one or more embodiments, the functionalized polyolefin
copolymers may be characterized by a melt flow of from about 0.3 to
about 2,000 dg/min, in other embodiments from about 0.5 to about
1,000 dg/min, and in other embodiments from about 1 to about 1,000
dg/min, per ASTM D-1238 at 230.degree. C. and 2.16 kg load. In one
or more embodiments, the functionalized polyolefin copolymers may
be characterized by a melt flow of less than 15, in other
embodiments less than 10, in other embodiments less than 7, in
other embodiments less than 5, and in other embodiments less than 4
dg/min, per ASTM D1238 at 230.degree. C. and 2.16 kg load.
[0037] In those embodiments where the functionalized polyolefin
copolymer has a melt temperature, the melt temperature is less than
30.degree. C., in other embodiments less than 20.degree. C., and in
other embodiments less than 5.degree. C. In one or more
embodiments, the functionalized polyolefin copolymer is
characterized by a glass transition temperature (Tg) of less than
20, in other embodiments less than 0, and in other embodiments less
than -10.degree. C. In these or other embodiments, the
functionalized polyolefin copolymer has a Tg of from about -50 to
about 10, in other embodiments from about -40 to about 0, and in
other embodiments from about -30 to about -10.degree. C.
[0038] The degree of functionalization of the functionalized
thermoplastic polymer may be recited in terms of the weight percent
of the pendent functional moiety based on the total weight of the
functionalized polyolefin copolymer. In one or more embodiments,
the functionalized thermoplastic polymer may include at least 0.2%
by weight, in other embodiments at least 0.4% by weight, in other
embodiments at least 0.6% by weight, and in other embodiments at
least 1.0 weight percent functionalization. In these or other
embodiments, the functionalized polyolefin copolymers may include
less than 10% by weight, in other embodiments less than 5% by
weight, in other embodiments less than 3% by weight, and in other
embodiments less than 2% by weight functionalization.
[0039] In one or more embodiments, the functionalized thermoplastic
polyolefin copolymer may be prepared by grafting a graft monomer to
a thermoplastic polyolefin copolymer. The process of grafting may
include combining, contacting, or reacting a thermoplastic polymer
with a graft monomer. These functionalized polyolefin copolymers
include those described in U.S. Pat. Nos. 4,957,968, 5,624,999,
6,503,984, 5,451,639, 4,382,128, 4,161,452, 4,137,185, and
4,089,794, which are incorporated herein by reference. In one or
more embodiments, the backbone of the functionalized polyolefin
copolymers may be synthesized by using an appropriate
polymerization technique known in the art. These techniques may
include conventional Ziegler-Natta, type polymerizations, catalysis
employing single-site organometallic catalysts including, but not
limited to, metallocene catalysts, and high-pressure free radical
polymerizations.
[0040] Functionalized polyolefin copolymers are commercially
available. For example, maleated polyolefin copolymer may be
obtained under the tradename EXXELOR VA 1801, 1202, 1803, 1840.TM.
(ExxonMobil).
Filler
[0041] In one or more embodiments, one or more layers of the
membranes employed in practicing the present invention may include
one or more filler materials including, but not limited to, mineral
fillers. In one or more embodiments, these fillers may include
inorganic materials that may aid in reinforcement, heat aging
resistance, green strength performance, and/or flame resistance. In
other embodiments, these materials are generally inert with respect
to the composition and therefore simply act as diluent to the
polymeric constituents. In one or more embodiments, mineral fillers
include clays, silicates, titanium dioxide, talc (magnesium
silicate), mica (mixtures of sodium and potassium aluminum
silicate), alumina trihydrate, antimony trioxide, calcium
carbonate, titanium dioxide, silica, magnesium hydroxide, calcium
borate ore, and mixtures thereof.
[0042] Suitable clays may include airfloated clays, water-washed
clays, calcined clays, surface-treated clays, chemically-modified
clays, and mixtures thereof.
[0043] Suitable silicates may include synthetic amorphous calcium
silicates, precipitated, amorphous sodium aluminosilicates, and
mixtures thereof.
[0044] Suitable silica (silicon dioxide) may include wet-processed,
hydrated silicas, crystalline silicas, and amorphous silicas
(noncrystalline).
[0045] In one or more embodiments, the fillers are not surface
modified or surface functionalized.
[0046] In one or more embodiments, the mineral fillers are
characterized by an average particle size of at least 1 .mu.m, in
other embodiments at least 2 .mu.m, in other embodiments at least 3
.mu.m, in other embodiments at least 4 .mu.m, and in other
embodiments at least 5 .mu.m. In these or other embodiments, the
mineral fillers are characterized by an average particle size of
less than 15 .mu.m, in other embodiments less than 12 .mu.m, in
other embodiments less than 10 .mu.m, and in other embodiments less
than 8 .mu.m. In these or other embodiments, the mineral filler has
an average particle size of between 1 and 15 .mu.m, in other
embodiments between 3 and 12 .mu.m, and in other embodiments
between 6 and 10 .mu.m.
Other Ingredients
[0047] One or more layers of the thermoplastic membranes employed
in the practice of this invention may also include other
ingredients such as those that are conventional in thermoplastic
membranes. In one or more embodiments, one or more layers of the
membranes employed in this invention may include stabilizers.
Stabilizers may include one or more of a UV stabilizer, an
antioxidant, and an antiozonant. UV stabilizers include Tinuvin.TM.
622. Antioxidants include Irganox.TM. 1010. For example, other
useful additives or constituents may include flame retardants,
stabilizers, pigments, and fillers.
Flame Retardants
[0048] In one or more embodiments, useful flame retardants include
and compound that will increase the burn resistivity, particularly
flame spread such as tested by UL 94 and/or UL 790, of the
laminates of the present invention. Useful flame retardants include
those that operate by forming a char-layer across the surface of a
specimen when exposed to a flame. Other flame retardants include
those that operate by releasing water upon thermal decomposition of
the flame retardant compound. Useful flame retardants may also be
categorized as halogenated flame retardants or non-halogenated
flame retardants.
[0049] Exemplary non-halogenated flame retardants include magnesium
hydroxide, aluminum trihydrate, zinc borate, ammonium
polyphosphate, melamine polyphosphate, and antimony oxide
(Sb.sub.2O.sub.3). Magnesium hydroxide (Mg(OH).sub.2) is
commercially available under the tradename Vertex.TM. 60, ammonium
polyphosphate is commercially available under the tradename
Exolite.TM. AP 760 (Clarian), which is sold together as a polyol
masterbatch, melamine polyphosphate is available under the
tradename Budit.TM. 3141 (Budenheim), and antimony oxide
(Sb.sub.2O.sub.3) is commercially available under the tradename
Fireshield.TM.. Those flame retardants from the foregoing list that
are believed to operate by forming a char layer include ammonium
polyphosphate and melamine polyphosphate.
[0050] In one or more embodiments, treated or functionalized
magnesium hydroxide may be employed. For example, magnesium oxide
treated with or reacted with a carboxylic acid or anhydride may be
employed. In one embodiment, the magnesium hydroxide may be treated
or reacted with stearic acid. In other embodiments, the magnesium
hydroxide may be treated with or reacted with certain
silicon-containing compounds. The silicon-containing compounds may
include silanes, polysiloxanes including silane reactive groups. In
other embodiments, the magnesium hydroxide may be treated with
maleic anhydride. Treated magnesium hydroxide is commercially
available. For example, Zerogen.TM. 50.
[0051] Examples of halogenated flame retardants may include
halogenated organic species or hydrocarbons such as
hexabromocyclododecane or
N,N'-ethylene-bis-(tetrabromophthalimide). Hexabromocyclododecane
is commercially available under the tradename CD-75P' (ChemTura).
N,N'-ethylene-bis-(tetrabromophthalimide) is commercially available
under the tradename Saytex.TM. BT-93 (Albemarle).
[0052] In one or more embodiments, one or more layers of the
membranes of the present invention may include expandable graphite,
which may also be referred to as expandable flake graphite,
intumescent flake graphite, or expandable flake. Generally,
expandable graphite includes intercalated graphite in which an
intercallant material is included between the graphite layers of
graphite crystal or particle. Examples of intercallant materials
include halogens, alkali metals, sulfates, nitrates, various
organic acids, aluminum chlorides, ferric chlorides, other metal
halides, arsenic sulfides, and thallium sulfides. In certain
embodiments of the present invention, the expandable graphite
includes non-halogenated intercallant materials. In certain
embodiments, the expandable graphite includes sulfate
intercallants, also referred to as graphite bisulfate. As is known
in the art, bisulfate intercalation is achieved by treating highly
crystalline natural flake graphite with a mixture of sulfuric acid
and other oxidizing agents which act to catalyze the sulfate
intercalation. Expandable graphite useful in the applications of
the present invention are generally known as described in
International Publ. No. WO/2014/078760, which is incorporated
herein by reference.
[0053] Commercially available examples of expandable graphite
include HPMS Expandable Graphite (HP Materials Solutions, Inc.,
Woodland Hills, Calif.) and Expandable Graphite Grades 1721 (Asbury
Carbons, Asbury, N.J.). Other commercial grades contemplated as
useful in the present invention include 1722, 3393, 3577, 3626, and
1722HT (Asbury Carbons, Asbury, N.J.).
[0054] In one or more embodiments, the expandable graphite may be
characterized as having a mean or average size in the range from
about 30 .mu.m to about 1.5 mm, in other embodiments from about 50
.mu.m to about 1.0 mm, and in other embodiments from about 180 to
about 850 .mu.m. In certain embodiments, the expandable graphite
may be characterized as having a mean or average size of at least
30 .mu.m, in other embodiments at least 44 .mu.m, in other
embodiments at least 180 .mu.m, and in other embodiments at least
300 .mu.m. In one or more embodiments, expandable graphite may be
characterized as having a mean or average size of at most 1.5 mm,
in other embodiments at most 1.0 mm, in other embodiments at most
850 .mu.m, in other embodiments at most 600 .mu.m, in yet other
embodiments at most 500 .mu.m, and in still other embodiments at
most 400 .mu.m. Useful expandable graphite includes Graphite Grade
#1721 (Asbury Carbons), which has a nominal size of greater than
300 .mu.m.
[0055] In one or more embodiments of the present invention, the
expandable graphite may be characterized as having a nominal
particle size of 20.times.50 (US sieve). US sieve 20 has an opening
equivalent to 0.841 mm and US sieve 50 has an opening equivalent to
0.297 mm. Therefore, a nominal particle size of 20.times.50
indicates the graphite particles are at least 0.297 mm and at most
0.841 mm.
[0056] In one or more embodiments, the expandable graphite may be
characterized by an onset temperature ranging from about
100.degree. C. to about 250.degree. C.; in other embodiments from
about 160.degree. C. to about 225.degree. C.; and in other
embodiments from about 180.degree. C. to about 200.degree. C. In
one or more embodiments, the expandable graphite may be
characterized by an onset temperature of at least 100.degree. C.,
in other embodiments at least 130.degree. C., in other embodiments
at least 160.degree. C., and in other embodiments at least
180.degree. C. In one or more embodiments, the expandable graphite
may be characterized by an onset temperature of at most 250.degree.
C., in other embodiments at most 225.degree. C., and in other
embodiments at most 200.degree. C. Onset temperature may also be
interchangeably referred to as expansion temperature; and may also
be referred to as the temperature at which expansion of the
graphite starts.
[0057] In one or more embodiments, one or more layers of the
membranes of the present invention include a nanoclay. Nanoclays
include the smectite clays, which may also be referred to as
layered silicate minerals. Useful clays are generally known as
described in U.S. Pat. No. 6,414,070 and U.S. Publ. No.
2009/0269565, which are incorporated herein by reference. In one or
more embodiments, these clays include exchangeable cations that can
be treated with organic swelling agents such as organic ammonium
ions, to intercalate the organic molecules between adjacent planar
silicate layers, thereby substantially increasing the interlayer
spacing. The expansion of the interlayer distance of the layered
silicate can facilitate the intercalation of the clay with other
materials. The interlayer spacing of the silicates can be further
increased by formation of the polymerized monomer chains between
the silicate layers. The intercalated silicate platelets act as a
nanoscale (sub-micron size) filler for the polymer.
[0058] Intercalation of the silicate layers in the clay can take
place either by cation exchange or by absorption. For intercalation
by absorption, dipolar functional organic molecules such as
nitrile, carboxylic acid, hydroxy, and pyrrolidone groups are
desirably present on the clay surface. Intercalation by absorption
can take place when either acid or non-acid clays are used as the
starting material. Cation exchange can take place if an ionic clay
containing ions such as, for example, Na.sup.+, K.sup.+, Ca.sup.++,
Ba.sup.++, and Li.sup.+ is used. Ionic clays can also absorb
dipolar organic molecules.
[0059] Smectite clays include, for example, montmorillonite,
saponite, beidellite, hectorite, and stevensite. In one or more
embodiments, the space between silicate layers may be from about 15
to about 40.times., and in other embodiments from about 17 to about
36.times., as measured by small angle X-ray scattering. Typically,
a clay with exchangeable cations such as sodium, calcium and
lithium ions may be used. Montmorillonite in the sodium exchanged
form is employed in one or more embodiments.
[0060] Organic swelling agents that can be used to treat the clay
include quaternary ammonium compound, excluding pyridinium ion,
such as, for example, poly(propylene glycol)bis(2-aminopropyl
ether), poly(vinylpyrrolidone), dodecylamine hydrochloride,
octadecylamine hydrochloride, and dodecylpyrrolidone. These treated
clays are commercially available. One or more of these swelling
agents can be used.
Amounts
Functionalized Polyolefin Copolymer
[0061] In one or more embodiments, the one or more layers of the
membranes of the present invention that include the functionalized
polyolefin copolymer include at least 1 weight percent, in other
embodiments at least 2 weight percent, in other embodiments at
least 3 weight percent, in other embodiments at least 4 weight
percent, and in other embodiments at least 5 weight percent of the
functionalized polyolefin copolymer (e.g. hydroxyl-bearing polymer)
based on the entire weight of the given layer of the membrane that
includes the functionalized polyolefin copolymer. In one or more
embodiments, the one or more layers of the membranes of the present
invention that include the functionalized polyolefin copolymer
include at most 20 weight percent, in other embodiments at most 15
weight percent, and in other embodiments at most 10 weight percent
of the functionalized polyolefin copolymer based on the entire
weight of the given layer of the membrane that includes the
functionalized polyolefin copolymer. In one or more embodiments,
the one or more layers of the membranes of the present invention
that include the functionalized polyolefin copolymer include from
about 1 to about 20, in other embodiments from about 2 to about 15,
and in other embodiments from about 3 to about 10 weight percent of
the functionalized polyolefin copolymer based upon the entire
weight of the given layer of the membrane that includes the
functionalized polyolefin copolymer.
Filler
[0062] As suggested above, one or more layers of the membranes of
the present invention, particularly those layers that include the
functionalized polyolefin copolymer, may include relatively high
loadings of filler (e.g. clay or calcium carbonate). Relatively
high levels of loading refers to an appreciable amount of filler.
In particular embodiments, the one or more layers of the membranes
employed in the present invention include at least 2 weight
percent, in other embodiments at least 5 weight percent, in other
embodiments at least 10 weight percent, in other embodiments at
least 15 weight percent, in other embodiments at least 20 weight
percent, in other embodiments at least 25 weight percent, in other
embodiments at least 30 weight percent, 33 weight percent, in other
embodiments at least 40 weight percent, and in other embodiments at
least 45 weight percent of the filler (e.g. mineral filler) based
on the entire weight of the given layer of the membrane that
includes the filler. In one or more embodiments, one or more layers
of the membranes of the present invention include at most 80 weight
percent, in other embodiments at most 70 weight percent, and in
other embodiments at most 60 weight percent of the filler based on
the entire weight of the given layer of the membrane that includes
the filler. In one or more embodiments, one or more layers of the
membranes of the present invention include from about 1 to about
80, in other embodiments from about 33 to about 80, in other
embodiments from about 2 to about 75 weight percent, in other
embodiments from about 10 to about 70, in other embodiments from
about 40 to about 70, in other embodiments from about 20 to about
65, in other embodiments from about 40 to about 60, and in other
embodiments from about 45 to about 55 weight percent of the filler
based upon the entire weight of the given layer of the membrane
that includes the filler.
Flame Retardants
[0063] In one or more embodiments, the one or more layers of the
membranes of the present invention that include the flame retardant
(e.g. magnesium hydroxide) include at least 5 weight percent, in
other embodiments at least 10 weight percent, in other embodiments
at least 20 weight percent, in other embodiments at least 25 weight
percent, and in other embodiments at least 30 weight percent of the
flame retardant (e.g. magnesium hydroxide) based on the entire
weight of the given layer of the membrane that includes the flame
retardant. In one or more embodiments, the one or more layers of
the membranes of the present invention that include the flame
retardant include at most 50 weight percent, in other embodiments
at most 45 weight percent, and in other embodiments at most 40
weight percent of the flame retardant based on the entire weight of
the given layer of the membrane that includes the flame retardant.
In one or more embodiments, the one or more layers of the membranes
of the present invention that include the flame retardant include
from about 5 to about 50, in other embodiments from about 10 to
about 45, and in other embodiments from about 20 to about 40 weight
percent of the flame retardant based upon the entire weight of the
given layer of the membrane that includes the flame retardant.
Specific Embodiments
[0064] Specific embodiments of the membranes employed in the
practice of the present invention can be described with reference
to FIG. 3. In one or more embodiments, the membranes employed in
the present invention may include functionalized polyolefin
copolymer in upper-middle layer 33, lower-middle layer 35,
optionally top layer 31, and optionally bottom layer 37. In
particular embodiments, while upper-middle layer 33 and lower
middle layer 35 may include functionalized polyolefin copolymer,
top layer 31 may be devoid of functionalized polyolefin
copolymer.
[0065] In one or more embodiments, bottom layer 37 includes
functionalized polyolefin copolymer. In one or more embodiments,
bottom layer 37 includes from about 1 to about 10, in other
embodiments from about 3 to about 8, and in other embodiments from
about 4 to about 6% by weight functionalized polyolefin copolymer,
based upon the entire weight of the layer.
[0066] In one or more particular embodiments, top layer 31,
upper-middle layer 33, lower-middle layer 35, and bottom layer 37
may include distinct amounts of one or more distinct or similar
fillers. For example, in one or more embodiments, top layer 31 may
include from about 15 to about 50, in other embodiments from about
20 to about 40, and in other embodiments from about 25 to about 35%
by weight magnesium hydroxide filler, based on the entire weight of
the layer, while upper-middle layer 33, lower-middle layer 35, and
bottom layer 37 include less than 20, in other embodiments less
than 10, and in other embodiments less than 5% by weight magnesium
hydroxide filler, based upon the entire weight of the respective
layers.
[0067] In one or more particular embodiments, at least one of
upper-middle layer 33, lower-middle layer 35, and bottom layer 37
individually include, or in certain embodiments each of layers 33,
35, and 37 include, from about 25 to about 75, in other embodiments
from about 35 to about 65, and in other embodiments from about 45
to about 65% by weight calcium carbonate filler, based on the
entire weight of the layer. As suggested above, these layers (i.e.,
layers 33, 35, and 37) each include functionalized polyolefin
copolymer.
Fully-Adhered Roofing System
[0068] The fully-adhered roofing systems of the present invention
can be described with reference to FIG. 4. Roofing system 40
includes a roof deck 51, optional insulation layer 53, optional
protection layer 55, optional existing membrane 57, adhesive layer
60, and membrane 71, where membrane 71 is a membrane according to
one or more embodiments of the present invention. For purposes of
this specification, the material to which the adhesive secures the
membrane, which is the uppermost layer, can be referred to as the
substrate. For example, where the membrane is adhesively secured to
an insulation board or layer, the insulation board or layer may be
referred to as a substrate.
[0069] Practice of this invention is not limited by the selection
of any particular roof deck. Accordingly, the roofing systems
herein can include a variety of roof decks. Exemplary roof decks
include concrete pads, steel decks, wood beams, and foamed concrete
decks.
[0070] In one or more embodiments, the existing membranes may
include cured rubber systems such as EPDM membranes, functionalized
polyolefin copolymers systems such as TPO membranes, or
asphalt-based systems such as modified asphalt membranes and/or
built roof systems.
[0071] Practice of this invention is likewise not limited by the
selection of any particular insulation board. Moreover, the
insulation boards are optional. Several insulation materials can be
employed including polyurethane or polyisocyanurate cellular
materials. These boards are known as described in U.S. Pat. Nos.
6,117,375, 6,044,604, 5,891,563, 5,573,092, U.S. Publ. Nos.
2004/0109983, 2003/0082365, 2003/0153656, 2003/0032351, and
2002/0013379, as well as U.S. application Ser. Nos. 10/640,895,
10/925,654, and 10/632,343, which are incorporated herein by
reference. As those skilled in the art appreciate, insulation
boards and cover boards may carry a variety of facer materials
including, but not limited to, paper facers, fiberglass-reinforced
paper facers, fiberglass facers, coated fiberglass facers, metal
facers such as aluminum facers, and solid facers such as wood.
[0072] In one or more embodiments, cover boards may include high
density polyurethane or polyisocyanurate board as disclosed in U.S.
Publ. Nos. 2006/0127664, 2013/0164524, 2014/0011008, 2013/0036694,
and 2012/0167510, which are incorporated herein by reference. In
other embodiments, the cover boards may include construction boards
such as DensDeck.
[0073] In other embodiments, these membranes may be employed to
cover flat or low-slope roofs following a re-roofing event. In one
or more embodiments, the membranes may be employed for re-roofing
as described in U.S. Publ. No. 2006/0179749, which is incorporated
herein by reference.
[0074] Practice of the present invention is also not necessarily
limited by the adhesive employed to bond the membrane to the
substrate. For example, the adhesive may include an adhesive that
forms a bond through curing action such as is the case with a
liquid bond adhesive (e.g. a butyl rubber adhesive) or a
polyurethane adhesive. In other embodiments, the adhesive may be a
pressure-sensitive adhesive, which may be applied to the membrane
at the location where the membrane is manufactured (e.g. a
factory-applied pressure-sensitive adhesive).
[0075] As used within the specification, the term "fully-adhered
roofing system" refers to a roofing system wherein the primary mode
of attachment of the membrane to the underlying substrate is
through the use of an adhesive. In one or more embodiments, this
mode of attachment includes the situation where at least 50%, in
other embodiments at least 70%, in other embodiments at least 90%,
and in other embodiments at least 98% of the underlying surface of
the membrane (i.e., the substrate-contacting planar surface of the
membrane) is adhered to the substrate through an adhesive.
Method of Making
[0076] In one or more embodiments, the membranes employed in the
present invention may be prepared by employing conventional
techniques. For example, the various ingredients can be separately
fed into an extruder and extruded into membrane and, optionally,
laminated into a laminate sheet. In other embodiments, the various
ingredients can be combined and mixed within a mixing apparatus
such as an internal mixer and then subsequently fabricated into
membrane sheets or laminates.
[0077] In one or more embodiments, the membranes of the present
invention may be prepared by extruding a polymeric composition into
a sheet. Multiple sheets may be extruded and joined to form a
laminate. A membrane including a reinforcing layer may be prepared
by extruding at least one sheet on and/or below a reinforcement
(e.g., a scrim). In other embodiments, the polymeric layer may be
prepared as separate sheets, and the sheets may then be calandered
with the scrim sandwiched there between to form a laminate. In one
or more embodiments, the membranes of the present invention are
prepared by employing co-extrusion technology. Useful techniques
include those described in co-pending U.S. application Ser. Nos.
11/708,898 and 11/708,903, which are incorporated herein by
reference.
[0078] Following extrusion, and after optionally joining one or
more polymeric layers, or optionally joining one or more polymeric
layer together with a reinforcement, the membrane may be fabricated
to a desired thickness. This may be accomplished by passing the
membrane through a set of squeeze rolls positioned at a desired
thickness. The membrane may then be allowed to cool and/or rolled
for shipment and/or storage.
[0079] The polymeric composition that may be extruded to form the
polymeric sheet may include the ingredients or constituents
described herein. For example, the polymeric composition may
include functionalized polyolefin copolymer, filler, and
functionalized polyolefin copolymers defined herein. The
ingredients may be mixed together by employing conventional polymer
mixing equipment and techniques. In one or more embodiments, an
extruder may be employed to mix the ingredients. For example,
single-screw or twin-screw extruders may be employed.
[0080] 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.
* * * * *