U.S. patent application number 11/291634 was filed with the patent office on 2007-06-21 for weatherproof underlayment with high filler content polymer asphalt layer.
This patent application is currently assigned to Northern Elastomeric, Inc.. Invention is credited to James Karlis, Thomas Zickell.
Application Number | 20070137130 11/291634 |
Document ID | / |
Family ID | 38110542 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070137130 |
Kind Code |
A1 |
Zickell; Thomas ; et
al. |
June 21, 2007 |
Weatherproof underlayment with high filler content polymer asphalt
layer
Abstract
A roofing membrane underlayment material includes a fibrous mat
generally encapsulated within a non-adhesive asphalt coating, the
resulting encapsulated mat having an adhesive asphalt layer applied
to one surface thereof, typically the bottom surface. An acrylic,
talc or granular coating is applied to the surface of the
encapsulated mat that is not in contact with the adhesive asphalt
layer. The non-adhesive asphalt coating is characterized in that it
includes a high filler content made possible by the use of
non-oxidized flux asphalt to which has been added a small
percentage of an asphalt additive such as radial or linear polymer
or other elastomer. The resulting membrane, when applied to a
roofing deck, provides a high traction surface that will not adhere
to shingles and provides an effective waterproofing seal on the
roofing deck and is flexible in both hot and cold environments.
Inventors: |
Zickell; Thomas; (New
Castle, NH) ; Karlis; James; (Pelham, NH) |
Correspondence
Address: |
BOURQUE & ASSOCIATES;INTELLECTUAL PROPERTY ATTORNEYS, P.A.
835 HANOVER STREET
SUITE 301
MANCHESTER
NH
03104
US
|
Assignee: |
Northern Elastomeric, Inc.
Brentwood
NH
|
Family ID: |
38110542 |
Appl. No.: |
11/291634 |
Filed: |
December 1, 2005 |
Current U.S.
Class: |
52/506.01 |
Current CPC
Class: |
E04D 12/002 20130101;
B32B 2333/04 20130101; Y10T 428/141 20150115; B32B 2260/021
20130101; B32B 11/10 20130101; B32B 2255/26 20130101; B32B 7/06
20130101; B32B 5/022 20130101; B32B 11/02 20130101; B32B 2037/243
20130101; B32B 2305/20 20130101; B32B 2395/00 20130101; B32B
2262/0253 20130101; B32B 2262/101 20130101; B32B 2307/744 20130101;
B32B 2419/06 20130101; B32B 2262/0276 20130101; B32B 38/08
20130101; Y10T 428/2848 20150115; B32B 2260/042 20130101; B32B
11/06 20130101; B32B 25/14 20130101; B32B 7/12 20130101; B32B
2307/7265 20130101; C08L 95/00 20130101; C08L 95/00 20130101; C08L
2666/08 20130101 |
Class at
Publication: |
052/506.01 |
International
Class: |
E04B 2/00 20060101
E04B002/00 |
Claims
1. A roofing membrane material comprising: a) fibrous mat having an
upper surface and a lower surface; b) a non-adhesive asphalt
coating applied to said fibrous mat and generally completely
saturating said fibrous mat and providing a layer of non-adhesive
asphalt at least on said upper surface of said fibrous mat, said
non-adhesive asphalt coating comprising an oxidized asphalt, a
non-oxidized asphalt, an asphalt additive selected from the group
consisting of an elastomer, a polymer and a plasticizer, and a
filler material; and c) an adhesive asphalt coating, applied to the
lower surface of the non-adhesive asphalt saturated mat.
2. The roofing membrane material of claim 1 wherein said elastomer
is a radial copolymer selected from the group consisting of
styrene-butadiene copolymers and styrene-butadiene-styrene
copolymers.
3. The roofing membrane material of claim 1 wherein said
non-adhesive asphalt coating includes approximately 0.5% to 3%
asphalt additive, 10% to 60% filler, 10% to 40% non-oxidized
asphalt and 10% to 40% to oxidized asphalt.
4. The roofing membrane material of claim 1 wherein said
non-adhesive asphalt coating includes approximately 2% asphalt
additive, 24% oxidized asphalt, 24% non-oxidized asphalt and 50%
filler.
5. The roofing membrane material of claim 1 wherein the fibrous mat
comprises a non-woven fibrous mat.
6. The roofing membrane material of claim 1 wherein the fibrous mat
comprises fibers selected from the group consisting of polyesters,
polypropylenes and fiberglass.
7. The roofing membrane material of claim 1 wherein the
encapsulated fibrous mat further includes a polymeric coating on at
least a portion of the upper surface of the mat.
8. The roofing membrane material of claim 6 wherein the polymeric
coating is provided with a coating of a finely-ground mineral.
9. The roofing membrane material of claim 6 wherein the
finely-ground mineral comprises talc.
10. The roofing membrane material of claim 6 wherein the polymeric
coating is selected from the group consisting of ethylene vinyl
acetate, polyurethanes, polyethylenes, latex, acrylic polymers and
polyesters.
11. The roofing membrane material of claim 1 which further
including a release sheet adhered to the adhesive asphalt
coating.
12. The roofing membrane material of claim 1 wherein the filler
material comprises limestone filler.
13. The roofing membrane material of claim 1 wherein the adhesive
asphalt coating comprises, in combination: a) flux asphalt; b) a
filler material; c) a material selected from the group consisting
of styrene-butadiene copolymers and styrene-butadiene-styrene
copolymers; and d) d) a tackifying oil.
14. The roofing membrane material of claim 13 wherein the filler
material comprises limestone filler.
15. A roofing membrane material which comprises in combination: a)
a fibrous mat having an upper surface and a lower surface; b) b) a
non-adhesive asphalt coating applied to and generally completely
saturating said fibrous mat, said non-adhesive asphalt coating
comprising approximately 0.5% to 3% copolymer, 10% to 60% filler,
10% to 40% non-oxidized asphalt and 10% to 40% to oxidized asphalt,
and wherein said copolymer is a radial copolymer selected from the
group consisting of styrene-butadiene copolymers and
styrene-butadiene-styrene copolymers; and c) c) an adhesive asphalt
coating applied to the lower surface of the asphalt saturated
fibrous mat.
16. The roofing membrane of claim 15 wherein the non-adhesive
polymeric coating is selected from the group consisting of ethylene
vinyl acetate and polyurethane.
17. The roofing membrane material of claim 15 wherein the adhesive
asphalt coating comprises, in combination: a) a flux asphalt; b) b)
a filler material; c) c) a material selected from the group
consisting of styrene-butadiene copolymers and
styrene-butadiene-styrene copolymers; and d) a tackifying oil.
Description
TECHNICAL FIELD
[0001] The present invention relates to roofing and other similar
underlayments and more particularly, to underlayments having a
fibrous mat having at least a top surface coated with an asphalt
layer including flux or non-oxidized asphalt, a copolymer and a
high filler content.
BACKGROUND INFORMATION
[0002] Asphalt based roofing shingles are presently installed on
approximately eighty percent of the homes in the United States. In
areas where snow accumulates, roof shingles can develop leaks as a
result of ice dams which can form along the eaves of a roof. Ice
dams form as the result of a differential temperature which occurs
between the eaves of the roof and the interior sections of the
roof. The temperature differential occurs when heat rises into the
attic space. Under certain temperature conditions, snow collected
on the roof surface will melt along the upper interior portions of
the roof and then freeze when the liquid snow-melt reaches the
cooler eave section of the roof. As can be seen in FIG. 1, the
result is that a pool 1 of liquid water can form between the roof
surface 2 and the ice dam 3. The ice dam 3 prevents the water from
reaching the gutter 4 and draining away. Ultimately, the liquid
water 1 can leak 5 through the roof surface 2, causing interior
water damage to the structure. Ice dams can also occur as a result
of frozen slush accumulating in gutters, also causing liquid to
collect and leak through the roof.
[0003] In a typical roofing installation using asphalt shingles, an
underlayment is first applied to the plywood deck of the roof. The
underlayment may take the form of an asphalt saturated paper which
is useful as a waterproofing member. Roofing shingles are applied
on top of the underlayment with the seams of adjacent rows.
positioned in an offset relationship. In practice, a starter row or
strip is begun at the roof eaves using self-sealing shingles. The
end of the first shingle in the strip is trimmed such that, when it
is placed on the deck, the cutouts of the first course of shingles
will not be placed over the starter strip joints. The starter strip
and the shingles are nailed to the eaves. Successive rows of
shingles are then secured to the deck or roof using nails.
[0004] To ensure maximum protection against ice dams, membranes or
metal flashing is installed wherever there is a possibility of
icing, such as along the eaves of the roof. As noted above, ice
dams are formed by the continual thawing and freezing of melting
snow, or the backing up of frozen slush in gutters, which force
water under the roofing, thereby causing damage to a structure's
ceilings, walls, and insulation. The ice damming problem is most
acute on lows-lope roofs; that is, roofs with a slope of two inches
(5.08 cm) to four inches (10.16 cm) per foot (30.48 cm).
[0005] Traditional eaves flashing has either been 50-pound coated
felt or two layers of 15-pound saturated felt cemented together.
The term "pound" is defined as the weight of the felt required to
cover an area of 108 square feet. Typically, the asphalt used in
the fifty-pound felt is not modified with rubber, and after aging,
will not form a good seal around nails. Additionally, the
installation of two layers of 15-pound saturated felt consumes
undesirable amounts of time and also will not seal around
nails.
[0006] The use of self-adhesive products, such as ice and water
protective membranes, has now become commonplace. One example of
such a product is described in the U.S. Pat. No. 6,531,200 which is
assigned to the assignee of the present invention and incorporated
fully herein by reference as well as its parent application, U.S.
Pat. No. 6,292,212. Although this and similar products have been
quite successful, the oxidized asphalt layer which is used to
impregnate the fibrous mat on the upper surface of the
underlayment, and which serves to allow the top surface of the
underlayment to be walked upon and not stick to the roofing
material, makes the finished product quite brittle. This problem is
particularly acute in Northern or other cold weather regions.
Finally, an additional problem is the rising cost of asphalt which
has considerably driven up the price to manufacture such a
product.
[0007] Accordingly, a need exists to produce a self-adhesive
waterproof underlayment which includes a top layer of oxidized
asphalt which can be walked upon by the installers, to which
roofing shingles will not stick and which is relatively bendable in
cold weather. In addition, a need also exists to attempt to reduce
the amount of asphalt required to manufacture such a product by
adding a high amount of filler material and thereby reduce the cost
of the finished product while at the same time insuring that the
quality, functionality and characteristics of the finished product
are essentially unchanged.
SUMMARY
[0008] The present invention relates to roofing membrane materials
having a fibrous mat surface which provides traction, structural
integrity and lap sealing capabilities. More particularly, the
present invention relates to a roofing membrane material having an
adhesive surface provided by an adhesive rubberized asphalt layer
and non-adhesive surface provided by a woven or non-woven fibrous
mat encapsulated within a non-adhesive asphalt coating. The
adhesive rubberized asphalt layer is very adherent and provides
excellent adhesion of the membrane to a roof deck, while the
encapsulated fibrous mat provides a surface having excellent
traction and lap sealing characteristics. A coating of material
such as a polyethylene composite or other polymers, minerals or the
like that adhere to the asphalt and provide a non-slip surface may
also be coated onto the non-adhesive top surface to enhance its
non-adhesive characteristics and provide traction.
[0009] In the preferred embodiment, traction is further enhanced by
providing granules of a particulate material embedded in the
non-adhesive top surface. The coating of the top surface prevents
shingles from adhering to the membrane, while the elastomer,
polymer or plasticizer makes the construction of the top layer
flexible in low temperatures. The preferred material for forming
the fibrous mat is fiberglass or polyester.
[0010] For preventing multiple layers of the membrane from adhering
to one another during shipping and storage, a release sheet can be
applied to the lower, adherent surface of the rubberized asphalt
layer. As a result of the release sheet, when the membrane is
rolled, or when several layers of the membrane are stacked
together, the release sheet is interposed between the sticky lower
surface of the rubberized asphalt and the adjacent traction layer.
By interposing the release sheet, adhesion between subsequent
layers of the membrane material is prevented. During application to
a roof surface, the release sheet is removed, thereby allowing the
sticky underside of the membrane to adhere to the roof.
[0011] One object of the present invention is to provide a
rubberized asphalt roofing product which can be applied along the
eaves of a roof to serve as a water infiltration barrier for the
overlying shingles and which is flexible in both hot and cold
weather and performs well in both hot and cold weather.
[0012] Another object of the present invention is to provide a
roofing membrane having a non-slip surface for the safety of roof
installers.
[0013] A further object of the invention is to provide a roofing
membrane that will not adhere to shingles, thereby allowing the
shingles to be easily removed and replaced, if necessary.
[0014] Yet another object of the invention is to reduce the cost of
the manufactured product by reducing the amount of asphalt needed
in the product by means of introducing a high amount of filler in
the oxidized asphalt coating.
[0015] It is important to note that the present invention is not
intended to be limited to a system or method which must satisfy one
or more of any stated objects or features of the invention. It is
also important to note that the present invention is not limited to
the preferred, exemplary, or primary embodiment(s) described
herein. Modifications and substitutions by one of ordinary skill in
the art are considered to be within the scope of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other features and advantages of the present
invention will be better understood by reading the following
detailed description, taken together with the drawings wherein:
[0017] FIG. 1 is a side elevational view of a portion of a roof
showing an ice dam;
[0018] FIG. 2 is a sectional view of the roofing membrane of the
present invention;
[0019] FIG. 3 is a schematic representation of one process for
manufacturing the roofing membrane of the present invention;
[0020] FIG. 4 is a perspective view of the eaves of a roof having
the membrane of the present invention, and several shingles,
applied thereto; and
[0021] FIG. 5 is a side elevational view of the portion of the roof
shown in FIG. 4, with the shingles removed for the purpose of
clarity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The present invention relates to self-adhesive membranes
which have been developed to eliminate problems associated with ice
dams and the like. The inventive membranes have a woven or
non-woven fibrous mat which is encapsulated within a relatively
non-adhesive asphalt composition. One surface of the coated mat is
provided with an acrylic coating which optionally contains
finely-ground particles of talc or other mineral materials. The
other surface of the encapsulated mat supports a rubberized asphalt
layer that adheres directly to the wood deck of a roof or other
substrate. Roof shingles may then be applied directly over the
membrane. The membrane prevents water entry into the structure by
adhering to the deck and sealing around the nails which are used to
hold the shingles to the roof deck. However, since the membrane has
been provided with a relatively non-adhesive asphalt upon which is
coated an acrylic material, shingles placed against the membrane do
not adhere to it, either upon placement or after an extended period
of time.
[0023] In a broad sense, the present invention comprises a roofing
membrane material having a traction layer formed by a fibrous mat
which is generally fully saturated with a relatively non-adhesive
asphalt, which asphalt extends generally to the top surface of the
mat. The mat further includes, on the bottom surface, an adhesive
asphalt coating such as that described below.
[0024] The relatively non-adhesive asphalt material on the top
surface, in the preferred embodiment, comprises a mixture of an
oxidized asphalt, a flux asphalt, an elastomer (sometimes referred
to as a polymer) (such as radial or linear SBS rubber) and fillers
such as talc and limestone. These components may be present over a
wide compositional range, but a ratio of approximately 2% radial
SBS polymer (such as styrene-butadiene copolymer or
styrene-butadiene-styrene copolymer), 50% filler, 24% flux asphalt
and approximately 24% oxidized asphalt is preferred although
various ranges of the various ingredients is contemplated by and
within the scope of the present invention. The inclusion of the
oxidized asphalt is desirable in that it is relatively inexpensive,
has excellent high temperature stability due to its Ring and Ball
melt point of about 225-250 degree F. (about 107-121 degree C.),
helps to create a non-stick, but safe walking surface and most
importantly, creates a less brittle product especially for cold
weather climates while also insuring flexibility in hot weather
without the asphalt softening so much that the surface becomes too
sticky or will give way underfoot.
[0025] Using a method that will be described in detail below, the
relatively non-adhesive asphaltic layer is applied to the fibrous
mat in a manner such that it infiltrates generally completely
through the mat's thickness while an adhesive asphalt layer is
provided on the other or intended bottom surface of the
encapsulated mat.
[0026] The fibrous mat may be any of a wide variety of woven or
non-woven materials. In one preferred embodiment, the fibrous mat
comprises a non-woven fiberglass mat. In another preferred
embodiment, the fibrous mat comprises a non-woven polyester mat.
The mat is preferably saturated at least proximate the top surface
with a generally non-adhesive material which comprises between 0.5%
to 5% elastomers, such as radial SBS rubber or linear SBS rubber;
15% to 65% filler; 5% to 60% of flux asphalt and between 10% to 80%
oxidized asphalt, and then coated with fine mineral granules (such
as talc or sand). The elastomer can be added as a liquid or an
undissolved solid to be mechanically dispersed during the mixing
process. An example of this would be ground tire rubber.
[0027] The asphalt coating tends to fill in gaps and porous regions
in the mat through which leaks could otherwise occur in sections of
the membrane which are lapped. Polymeric or elastomeric
strengthening of the membrane is desired because the membrane must
meet an ASTM tensile strength requirement of 25 pounds per inch.
The strength of the polymer thereby allows a lighter glass mat to
be used.
[0028] In the preferred embodiment, the mat is preferably generally
saturated with an asphalt comprising approximately 2% radial SBS
polymer (this type of material is also referred to in the art as an
elastomer); 50% filler; 24% of flux asphalt (having a melt point of
approximately 100.degree.) and approximately 24% oxidized asphalt
(having a melt point of approximately 220.degree.). The polymer
mixed with the flux asphalt tends to make the coating much less
brittle while the inclusion of approximately 50% filler in such a
mixture makes the coating much less expensive and that less asphalt
is required.
[0029] When using a fiberglass mat, a non-woven fiberglass weighing
between one to three pounds per hundred square feet (about
0.05-0.15 kg/m.sup.2), preferably about two pounds per hundred
square feet (about 0.10 kg/m.sup.2), is used. The polymeric
composition that is applied to the asphalt-saturated mat can be
selected from any of a wide variety of polymeric materials. For
example, polyurethanes, polyethylenes, latex, ethylene vinyl
acetate (EVA), acrylic polymers and polyesters all may be used. In
one preferred embodiment, the polymeric composition is a composite
of an acrylic and a low molecular weight polyethylene. In another
preferred embodiment, the polymer comprises a UV curable
polyurethane. In still another preferred embodiment, the
encapsulated mat is provided with a coating of polyethylene.
[0030] It should be noted, however, that the invention is not
intended to be limited to polymeric coated embodiments. Rather, any
of a wide variety of fibrous mat materials, including, but not
limited to, woven and non-woven polyesters and polypropylenes, with
or without polymeric coatings, may be used. For example, in one
preferred embodiment, the mat comprises a non-woven polyester,
preferably weighing between about 2.22 to about 4.88 pounds per
hundred square feet, (about 0.11-0.24 kg/m.sup.2) encapsulated in
the asphalt composition.
[0031] Likewise, the invention is not intended to be strictly
limited to embodiments in which the fibrous mat is completely
encapsulated or saturated in an asphaltic material. Rather, in one
embodiment, the mat may be encapsulated within a polymeric material
such as ethylene vinyl acetate (EVA) or a polyurethane. Such an
encapsulated mat would still employ the adhesive asphalt layer to
adhere the membrane to the roofing deck, and may optionally include
a coating on its upper surface to minimize sticking when the
product is rolled and when installers are walking on the product,
and/or a finely-ground mineral layer such as talc.
[0032] In still another embodiment, the membrane comprises a mat
formed of a non-woven polymer, such as polyester that has its lower
surface coated with a non-adhesive, filled asphalt. An adhesive
asphalt is then coated onto the non-adhesive asphalt layer in order
to provide a surface which readily adheres to the roofing deck. As
above, the non-adhesive filled asphalt preferably comprises a
composition of approximately 2% radial SBS polymer; 50% filler; 24%
of flux asphalt (having a melt point of approximately 100.degree.)
and approximately 24% oxidized asphalt (having a melt point of
approximately 220.degree.). This embodiment does not require a
polymeric or finely-ground mineral coating on its upper surface,
although, if desired, one or more of those may be employed.
[0033] The adhesive asphalt coating formed on one side of the mat
generally comprises a material having from about 0-45% mineral
stabilizer, (i.e., powdered limestone), about 0.5-15%
styrene-butadiene copolymer or styrene-butadiene-styrene copolymer
(radial or linear), and the balance being flux asphalt having a
Ring and Ball softening point of between about 80 to 150 degree F.
Additionally, a tackifying oil, such as Hydrolene may be added.
This second layer of material, being adhesive, is used to adhere
the membrane to the roof deck.
[0034] A release sheet, as described below, can be adhered to the
adhesive material to protect the adhesive properties during
transport and storage of the membrane.
[0035] FIG. 2 depicts a roofing membrane material 10 according to
one embodiment of the present invention. More particularly, as can
be seen in FIG. 2, the roofing membrane material 10 comprises a
multilayered structure formed of a fibrous mat 12, generally
encapsulated entirely within a relatively non-adhesive asphalt
composition 14, 16, to form an encapsulated mat 18, and an
adhesive, rubberized asphalt layer 20 disposed on one surface of
the encapsulated fibrous mat 18. A coating 22, such as acrylic, is
formed on the other surface of the encapsulated mat. Talc may be
applied to the coating, or granular particles may be embedded
therein, to further enhance traction upon the non-adhesive
surface.
[0036] Optionally, a release sheet 24, such as a paper or plastic
film 26 having a siliconized surface 28 can be adhered to the
relatively adhesive portion 20 of the membrane 10. The release
sheet 24 is removed prior to use of the membrane material to allow
the adhesive portion 20 of the membrane to be adhered to a roof
surface. The release layer 24 is typically a paper sheet 26 having
a siliconized surface 28. As an alternative, the release layer can
comprise two separate sheets; a first supporting sheet of a paper
or polymeric film, and a second sheet of a low surface energy
material. Additionally, in the case of a siliconized paper, the
silicon coating may be replaced by some other suitable low surface
energy material such as a wax emulsion or a soap solution.
[0037] As can also been seen in FIG. 2, the invention is
characterized in that the non-adhesive asphalt 14, 16 infiltrates
generally completely through the fibrous mat 12. In so doing, the
non-adhesive material serves to seal the mat 12, without detracting
from the mat's particular non-slip properties on its top surface.
As noted previously, and especially when formed from fiberglass, a
polymeric coating may be applied to the mat to further seal it and
to enhance its non-slip characteristics.
[0038] The above-described structure addresses many of the needs
currently embodied in the roofing industry including the novel
feature of a more ductile and less costly underlayment membrane.
For example, the membrane provides a good seal between the decking
of the roof surface and the roofing shingles to prevent moisture
from penetrating into the roof, even if ice dams are formed on the
eaves of the roof. The membrane also elongates and recovers around
the nails, thereby providing an excellent seal around nails that
pass through the membrane to secure shingles to the decking forming
the roof surface. In addition, the fibrous mat 12 serves to provide
a non-slip surface to the portion of the membrane material that
will be walked upon by roofing installers. This non-slip surface
offers the installers greater traction, and thus, greater safety,
when installing the roof, even in wet or otherwise slippery
conditions. Furthermore, the non-adhesive asphalt and acrylic
layers do not stick to shingles that are layered above them,
thereby allowing the shingles to be removed and replaced without
the need to replace underlying roof decking. Most importantly, the
membrane remains less brittle in cold weather due to the addition
of the copolymer and flux asphalt in the encapsulated in asphalt
layers while the provision of a high ratio of filler significantly
reduces the cost associated with the asphalt.
[0039] Membranes of the present invention are made using a
continuous, multi-coating process. One embodiment of the process is
shown in FIG. 3. As shown n FIG. 3, a web 40 of the fibrous
material is passed through several coating stations. The first
coating station 42 comprises an asphalt supply pipe 44 which
provides an excess of the non-adhesive asphalt material 46 to the
upper surface of the web. Excess non-adhesive asphalt material 46
flows over the web and into a first coating bath tank 48.
[0040] As stated above, the non-adhesive asphalt material 46
includes, in combination, oxidized asphalt, flux asphalt, filler
and a radial copolymer. Because the radial copolymer will not mix
well, if at all, with the oxidized asphalt, the preparation of the
non-adhesive asphalt material 46 must proceed in a special
manner.
[0041] First, the radial copolymer must be mixed with the flux
asphalt. This step is performed in a high shear mill as is well
known in the art. Typically, approximately 2% of the finished
composition will be radial copolymer while approximately 24% of the
finished product will be flux or non-oxidized asphalt although
various blends and ratios are contemplated by the present
invention. It has been found that if the oxidized asphalt is added
at the same time as the radial copolymer, the radial copolymer will
not disperse within the mixture.
[0042] Next, the oxidized asphalt is added in an amount comprising
approximately 24% of the finished compound. Finally, a filler, such
as limestone, is added in a percentage equaling approximately 50%
of the finished. compound. It should be noted that it is possible
to add both the oxidized asphalt and the filler simultaneously to
the copolymer/flux asphalt mixture. The addition of such a high
percentage of filler helps to reduce the cost of the mixture while
the radial copolymer provides the desired flexibility
characteristics in cold weather.
[0043] Although preferred percentages of the composition as well as
component content ranges have been given above, it will be apparent
to someone skilled in the art, with the benefit of the present
disclosure, that adding too much oxidized asphalt will make the
product more brittle. It is desirable to have only enough flux or
non-oxidized asphalt to be able to dissolve or absorb the radial or
linear copolymer. If the percentage of non-oxidized asphalt is too
high, the top surface will be sticky and will not be a walkable
surface. As the amount of oxidized asphalt is raised, the amount of
non-oxidized asphalt is lowered. As the amount of filler is raised,
the amounts of oxidized and non-oxidized asphalt are lowered. in
addition, it has been found that copolymers or elastomers from
different suppliers have slightly different characteristics and the
amount of copolymer vis-a-vis the amount of non-oxidized asphalt
will have to be adjusted accordingly. Without limiting the claims
of the present invention, various exemplary and presently preferred
formulas and ratios are disclosed herein, although this is not to
be construed as a limitation of the present invention.
[0044] A roller applicator 50 simultaneously applies the
non-adhesive asphalt material 46 to the lower surface of the web
40. The coated web is then scraped on its upper surface by an upper
doctor blade 52 and on its lower surface by a lower doctor blade
54. The doctor blades serve to maintain the non-adhesive asphalt
coating at a predetermined thickness.
[0045] Next, the web then passes below one or more acrylic spray
heads 56, which spray an aqueous solution 58 of the acrylic coating
onto the upper surface of the web. The aqueous acrylic solution is
applied immediately after the web passes the first coating station
42. As such the web is still hot, due to the coating of heated
asphalt which has just been applied. The heat of the web
(preferably about 175. degrees C.) causes the aqueous portion of
the aqueous acrylic solution to evaporate, leaving behind the
acrylic material. The heat of the web also causes the acrylic
material to begin curing.
[0046] The web then passes to a second coating bath station 60. In
the second coating bath station 60, heated adhesive, rubberized
asphalt material 62 is contained in a second coating bath tank 64
and applied to the underside of the web 40 by a roller applicator
66. The thickness of the coating is controlled using a rolling,
heated pipe positioned immediately downstream of the roller
applicator 66.
[0047] As noted previously, an additional coating such as talc or
granular particles may be applied to the upper surface of the
membrane. This coating serves to fill gaps where the acrylic may
have not fully coated the asphalt surface. In so doing, the talc
prevents the membrane material from sticking to itself when rolled.
If desired, for example, talc may be applied as follows. A talc
supply pipe 70 provides a mixture of talc/water and/or talc/polymer
mixture 72 to the upper surface of the web. This material combines
with the partially cured acrylic and fills any voids that may be
present in the acrylic coating. The talc mixture is metered on the
web surface using a silicone-coated rubber roller 74 and one or
more air blowers 78 that force excess talc mixture into a catch
tray 76. The remaining talc/water mixture dries during subsequent
manufacturing steps, leaving a coating of talc on the upper,
acrylic surface of the web 40.
[0048] Applying talc from a water mixture is advantageous in that
the water portion of the mixture is a convenient, low cost carrier
for the talc, which also serves to cool the acrylic coating to
prevent it from sticking to the process machinery during
manufacture. It is additionally advantageous since the web must be
cooled prior to the application of the release sheet (not shown) to
the lower surface of the web.
[0049] The release sheet can be applied by any of a wide variety of
methods known to those skilled in the art of web handling and
processing. It is noted that the present invention is not intended
to be limited to the particular method described above. This method
has been described for illustration purposes, however, it should be
understood that many other methods for forming the inventive
membrane may be available to those of ordinary skill in the
art.
[0050] The resulting membrane product comprises a fibrous mat
encapsulated within a non-adhesive asphalt material. The
encapsulated mat will have an adhesive asphalt affixed to its lower
surface, and an acrylic layer affixed to its upper surface. Talc or
particulate granules may optionally be deposited on or in the
acrylic layer. To aid in shipping, storing and handling the
membrane, a release sheet may be applied to the adhesive asphalt
layer.
[0051] FIGS. 4 and 5 show the manner in which the membrane material
10 is intended for use on a roof deck 36 in the region, for
exemplary purposes only, of the roof eaves 38. In applying the
present invention, eave flashing is replaced by the membrane 10
described herein. In use, the release sheet 24 is removed from the
lower surface of the double asphaltic layer 18, and the membrane 10
is secured to the roof deck 36 by adhesive action. The membrane 10
is positioned along the leading edge of the roof. Subsequently, a
first row of shingles 37 is positioned in an overlying relationship
to the membrane 10. The shingles are secured in place using nails
39. Although the roofing installer will often be caused to stand on
the membrane during installation of the shingles, the fibrous mat
of the inventive membrane 10 provides sufficient friction to
minimize the likelihood of slipping. Thus, as compared to many of
the known roofing membranes, the membranes of the present invention
provide a safer work surface.
[0052] As mentioned above, the present invention is not intended to
be limited to a system or method which must satisfy one or more of
any stated or implied object or feature of the invention and should
not be limited to the preferred, exemplary, or primary
embodiment(s) described herein. Modifications and substitutions by
one of ordinary skill in the art are considered to be within the
scope of the present invention, which is not to be limited except
by the allowed claims and their equivalents.
* * * * *