Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ON 142-03
MINERAL-SURFACED ROOFING SHINGLES WITH INCREASED SOLAR
HEAT REFLECTANCE, AND PROCESS FOR PRODUCING SAME
10
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The present invention relates to bituminous roofing products such. as asphalt
shingles and processes for making such roofing products.
2. Brief Description of the Prior Art.
Roofing products such as asphalt shingles are typically composite articles
including a nonwoven glass fiber or felt web covered with a coating of water
repellent
bituminous material, and'surfaced with protective mineral-based roofing
granules.
The bituminous material is characteristically black in color, and is strongly
absorptive of incident solar radiation.
Pigment-coated mineral rocks are commonly used as color granules in roofing
applications to provide aesthetic as well as protective functions to the
asphalt
shingles. Roofing granules are generally used in asphalt shingle or in roofing
membranes to protect asphalt from harmful ultraviolet radiation.
Mineral surfaced asphalt shingles, such as those described in ASTM D225 or
D3462, are generally used in steep-sloped roofs to provide water-shedding
function
while adding aesthetically pleasing appearance to the roofs. The asphalt
shingles are,
generally constructed from asphalt-saturated roofing felts and surfaced by
pigmented
color granules, e.g., as those described in U.S. Patent 4,717,614. However,
such
asphalt shingles are known to have low solar reflectivity and hence will
absorb solar
heat especially through the near infrared range of the solar spectrum.
This phenomenon increases as the granules covering the surface become dark
in color. For example, the white-colored asphalt shingles with CIE L* > 60 can
have
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solar reflectance greater than 25% (ASTM E1918 method), whereas the non-white
asphalt shingles with L* < 60 can only have solar reflectance in the range of
5-20%. As
a result, it is common to measure temperatures as high as 160 - 170 F (71 - 77
degrees Centigrade) on the surface of dark roofing shingles in a sunny day
with 80 F
(27 degree Centigrade) ambient temperature.
Absorption of solar heat may result in elevated temperatures at the shingles'
surroundings, which can contribute to the so-called "heat-island" effects and
increase
the energy load required to cool the surroundings.
In order to address this problem, externally applied coatings have sometimes
been applied directly onto the shingle surface on the roof. White pigment-
containing
latex coatings have been proposed.
The use of exterior-grade coatings colored by infrared-reflective pigments for
deep-tone colors has also been proposed for spraying onto the roof in the
field. U.S.
Patent Application Publication No. 2003/0068469A1 discloses an asphalt-based
roofing
material comprising mat saturated with asphalt coating and a top coating
having a top
surface layer that has a solar reflectance of at least 70%.
U.S. Patent Application Publication No. 2002/0160151 Al discloses an
integrated granule product comprising a film having a plurality of ceramic-
coated
granules bonded to the film by a cured adhesive and the cured adhesive or the
film can
have pigments. Such integrated granule product can be directly bonded to an
asphalt-
based substrate as roofing products.
Roofing granules typically comprise crushed and screened mineral materials,
which are subsequently coated with a binder containing one or more coloring
pigments, such as suitable metal oxides. The binder can be a soluble alkaline
silicate
that is subsequently insolubilized by heat or by chemical reaction, such as by
reaction
between an acidic material and the alkaline silicate, resulting in an
insoluble colored
coating on the mineral particles. Preparation of colored, coated roofing
granules is
disclosed for example, in U.S. Patent 2,981,636 of Lodge et al. The granules
are
then employed to provide a protective layer on asphaltic roofing materials
such as
shingles, and to add aesthetic values to a roof.
Pigments for roofing granules have usually been selected to provide shingles
having an attractive appearance, with little thought to the thermal stresses
encountered on shingled roofs. However, depending on location and climate,
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shingled roofs can experience very challenging environmental conditions, which
tend
to reduce the effective service life of such roofs. The elevated temperature
experienced by roofing shingles under sunny, summer conditions is a
significant
environmental stress, especially for roofing shingles coated with dark colored
roofing
granules. Although such roofs can be coated with solar reflective paint or
coating
material, such as a composition containing a significant amount of titanium
dioxide
pigment, in order to reduce such thermal stresses, this utilitarian approach
will often
prove to be aesthetically undesirable, especially for residential roofs.
Asphalt shingles coated with conventional roofing granules are known to
have low solar heat reflectance, and hence will absorb solar heat especially
through
the near infrared range (700 nm - 2500 nm) of the solar spectrum. This
phenomenon increases as the granules covering the surface become dark in
color.
For example, while white-colored asphalt shingles can have solar
reflectance in the range of 25-35%, dark-colored asphalt shingles can have
solar
reflectance in the range of only 5-15%. Furthermore, except in the white or
very
light colors, there is typically only a very small amount of pigment in the
conventional granule's color coating that reflects solar radiation well.
There is a need for an asphalt shingle that has solar reflectivity greater
than
25% to reduce the solar heat absorption, while providing aesthetically
pleasing, non-
white colors to maintain the aesthetic value of roofing assembly.
There is a continuing need for roofing materials, and especially asphalt
shingles, that have improved resistance to thermal stresses while providing an
attractive appearance.
In particular, there is a need for roofing shingles that provide increased
solar
heat reflectance to reduce the solar absorption of the shingles, while
providing a
wide range of colors including deep-tone colors to maintain the aesthetic
value of
the system.
SUMMARY OF THE INVENTION
The present invention provides roofing shingles that provide increased solar
heat reflectance, while providing deep-tone colors, as well as processes for
their
production.
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In a presently preferred first embodiment, the present invention provides a
method for making an infrared-reflective, deep-tone roofing product. This
method
comprises coating a fibrous web with a bituminous coating at an elevated
temperature to form a bitumen-coated web, applying at least one powder of an
infrared-reflective material to the bitumen-coated web, and then applying
roofing
granules to the bitumen-coated web.
In a presently preferred first embodiment, the present invention also provides
an infrared-reflective, deep-tone roofing product, in the form, for example,
of asphalt
shingles. This roofing product comprises a fibrous web coated with a
bituminous
coating forming a bitumen-coated web, a coating of at least one powder of an
infrared-reflective material applied to the bitumen-coated web, and roofing
granules
applied to the bitumen-coated web.
In a second presently preferred embodiment, the present invention provides a
second method for making an infrared-reflective, deep-tone roofing product.
The
second method comprises coating a fibrous web with a bituminous coating at an
elevated temperature to form a bitumen-coated web, and applying a coating
material
to the bitumen-coated web. The coating material comprises a carrier, and at
least
one powder of an infrared-reflective material to the bitumen-coated web. The
second
method further comprises applying roofing granules to the bitumen-coated web.
Preferably, the coating material has a melting or softening temperature less
than the surface temperature of the bitumen-coated web, such that the coating
material melts or softens upon application to the bitumen-coated web.
In a second presently preferred embodiment, the present invention provides a
second infrared-reflective, deep-tone roofing product. The second roofing
product
comprises a fibrous web coated with a bituminous coating forming a bitumen-
coated
web, a coating material including a carrier and at least one powder of an
infrared-
reflective material applied to the bitumen-coated web, and roofing granules
applied to
the bitumen-coated web.
In a third presently preferred embodiment, the present invention provides a
third method for making an infrared-reflective, deep-tone roofing product. The
third
method comprises coating a fibrous web with a bituminous coating at an
elevated
temperature to form a bitumen-coated web, and applying a coating film to the
bitumen-coated web. The coating film comprises a film carrier, and at least
one
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powder of an infrared-reflective material to the bitumen-coated web. The
method
further comprises applying roofing granules to the bitumen-coated web.
Preferably,
the coating film has a melting temperature less than the surface temperature
of the
bitumen-coated web, and the coating film melts, preferably at least partially,
upon
application to the bitumen-coated web to adhere the coating film to the
bitumen-
coated web. Preferably, the coating film upon melting also helps to adhere the
roofing granules to the bitumen-coated web.
In a third presently preferred embodiment, the present invention provides a
third infrared-reflective, deep-tone roofing product. This third infrared-
reflective,
deep-tone roofing product comprises a fibrous web coated with a bituminous
coating
forming a bitumen-coated web, a coating film including a film carrier and at
least one
powder of an infrared-reflective material applied to the bitumen-coated web,
and
roofing granules applied to the bitumen-coated web.
In a fourth presently preferred embodiment, the present invention provides a
fourth method for making an infrared-reflective, deep-tone roofing product.
The fourth
method comprises a method for making an infrared-reflective, deep-tone roofing
product. The method comprises coating a fibrous web with a bituminous coating
at
an elevated temperature to form a bitumen-coated web, and then applying a
coating
web to the bitumen-coated web. The coating web comprises a web carrier, at
least
one powder of an infrared-reflective material adhered to the bitumen-coated
web, and
roofing granules. Preferably, the'web carrier has a melting temperature less
than the
surface temperature of the bitumen-coated web, and the web carrier melts,
preferably
at least partially, upon application to the bitumen-coated web.
In a fourth presently preferred embodiment, the present invention provides a
fourth infrared-reflective, deep-tone roofing product. This fourth infrared-
reflective,
deep-tone roofing product comprises a fibrous web coated with a bituminous
coating
forming a bitumen-coated web, and a coating web including a web carrier, at
least
one powder of an infrared-reflective material and roofing granules, the
coating web
being applied to the bitumen-coated web.
In a fifth presently preferred embodiment, the present invention provides a
fifth
method for making an infrared-reflective, deep-tone roofing product. The fifth
method
comprises coating a fibrous web with a bituminous coating at an elevated
temperature to form a bitumen-coated web, applying roofing granules to the
bitumen-
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coated web to form an intermediate product; and applying a coating film to the
intermediate product. Optionally, additional heat may be applied to fuse the
coating
film to the intermediate product. The coating film comprises a film carrier,
and at least
one powder of an infrared-reflective material. Preferably, the coating film
has a
melting temperature less than the surface temperature of the intermediate
product,
and the coating film melts upon application to the intermediate product to
adhere the
coating film to the intermediate product. Alternatively, the coating film may
be applied
to the intermediate product and subsequently provided with heat to adhere the
coating film to the intermediate product.
In a fifth presently preferred embodiment, the present invention provides a
fifth
infrared-reflective, deep-tone roofing product. This fifth infrared-
reflective, deep-tone
roofing product comprises a fibrous web coated with a bituminous coating
forming a
bitumen-coated web, roofing granules applied to the bitumen-coated web to form
an
intermediate product, and a coating film including a film carrier and at least
one
powder of an infrared-reflective material applied to the intermediate product.
In a sixth presently preferred embodiment, the present invention provides a
sixth method for making an infrared-reflective, deep-tone roofing product. The
sixth
method comprises coating a fibrous web with a bituminous coating at an
elevated
temperature to form a bitumen-coated web, applying roofing granules to the
bitumen-
coated web to form an intermediate product; and applying a coating material to
the
intermediate product. The coating material comprises a fluid carrier, and at
least one
powder of an infrared-reflective material.
Preferably, in each of the above embodiments, the roofing granules comprise
infrared-reflective roofing. granules. However, the roofing granules can
comprise
conventional roofing granules or a blend of conventional roofing granules and
infrared-reflective roofing granules.
Preferably, in each of the above embodiments, the at least one powder is
selected from the group consisting of titanium dioxide pigments, nickel
titanate
pigments, chrome titanate pigments, nano-Ti02 particles, light-interference
platelet
pigments, pearlescent pigments, metal-oxide coated substrate pigments, iron
oxide
yellow pigments, iron titanium oxides, metal flakes, light-scattering
pigments, and
mirrorized fillers. It is also preferred in each of the above embodiments that
the colored
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infrared-reflective roofing product has an L* value of less than 55 and a
solar
reflectance of greater than 25 percent.
The above-referenced presently preferred embodiments of the method of the
present invention provide infrared-reflective material in between the portions
of the
surface of the roofing product covered by roofing granules. Preferably, the
above-
referenced methods of the present invention provide infrared-reflective
material to
cover at least 75 percent of the surface area of the roofing product not
otherwise
covered by roofing granules, more preferably at least about 90 percent, and
even more
preferably at least about 95 percent.
In a seventh presently preferred embodiment, the present invention provides a
seventh method for making infrared-reflective roofing products. The seventh
method
comprises coating a fibrous web with a bituminous coating at an elevated
temperature to form a bitumen-coated web; applying roofing granules to the
bitumen-
coated web, the roofing granules including (a) at least 50 percent by weight
off-white
mineral particles comprising A12O3 and SiO2, and having a solar reflectance
greater
than 30 percent while having and L* of less than about 60 percent, and (b)
mineral
particles selected from the group consisting of conventional colored roofing
granules,
and infrared-reflective roofing granules. In this embodiment, the aluminum
oxide
content is preferably less than that of silicon dioxide in order that the
granules have
an off-white color.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic illustration of the structure of an infrared-
reflective,
deep-tone roofing product according to a first embodiment of the present
invention.
Figure 2 is a schematic illustration of the structure of an infrared-
reflective
roofing product according to a second embodiment of the present invention.
Figure 3 is a schematic illustration of the structure of an infrared-
reflective
roofing product according to a third embodiment of the present invention.
Figure 4 is a schematic illustration of the structure of an infrared-
reflective
roofing product according to a fourth embodiment of the present invention.
Figure 5 is a schematic illustration of the structure of an infrared-
reflective
roofing product according to a fifth embodiment of the present invention.
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Figure 6 is a schematic illustration of the structure of an infrared-
reflective
roofing product according to a sixth embodiment of the present invention.
Figure 7 is a schematic illustration of the structure of an infrared-
reflective,
deep-tone roofing product according to a variation of first embodiment of the
present
invention.
Figure 8 is a schematic illustration of the structure of an infrared-
reflective
roofing product according to a seventh embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides solutions to problems associated with the high
solar energy absorption of deep-tone asphalt-based roofing shingles. As used
in the
present specification and claims, unless otherwise indicated, "deep-tone" is
defined to
mean a color having a CIE color parameter L* < 60.
As used in the present specification, "colored" means having an L* value of
less than 85, preferably less than 55, even more preferably less than 45, when
measured using a HunterLab Model Labscan XE spectrophotometer using a 0
degree viewing angle, a 45 degree illumination angle, a 10 degree standard
observer, and a D-65 illuminant. "Colored" as so defined is intended to
include
relatively dark tones.
As used in the present specification, the strength in color space E* is
defined
as E* = (L*2 + a*2 + b*2)112, where L*, a*, and b* are the color measurements
for a
given sample using the 1976 CIE L*a*b* color space. The total color difference
DE*
is defined as AE* = (AL*2 + i a*2 + Ab*2)112 where AL*, Da*, and Ab* are
respectively
the differences in L*, a* and b* for two different color measurements.
In one aspect of the bituminous roofing products of the present invention, the
colored roofing granules have increased solar heat reflectance in comparison
with
conventional colored roofing granules. In another aspect of the present
invention, the
bituminous coating of the roofing product has increased solar heat
reflectance. In yet
another aspect of the present invention, both the colored roofing granules and
the
bituminous coating have increased solar heat reflectance.
In the present specification and claims, the terms "solar heat reflectance"
and
"infrared reflectance" are used interchangeably.
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Since 80-90% of the surface of an asphalt shingle is covered by pigmented
roofing granules, it is desirable to first increase the solar reflectance of
the roofing
granules, especially in the near infrared range of solar-heating spectrum.
Methods to produce colored roofing granules with higher solar reflectance and
such roofing granules are disclosed in U.S. Patent Application Serial No.
10/679,898,
filed October 6, 2003. These colored
roofing granules with higher solar heat reflectance can be directly
incorporated into
traditional shingle manufacturing lines to enhance shingle solar heat
reflectance.
In addition, the solar heat reflectance of the 10-20% asphalt coating area
exposed to solar radiation can be increased by the processes of the present
invention.
For light-colored roofing products, such as light-colored asphalt shingles
with
50<L*<60 and solar reflectance between 18% to less than 25%, the solar heat
reflectance of the roofing product can be increased to above 25% by increasing
the
solar heat reflectance of the bituminous coating or areas of the top surface
of the
shingle not covered by roofing granules using methods described below, without
the
need to enhance the solar heat reflectance of existing colored roofing
granules.
For deep-tone roofing products with L*<50, the infrared reflectance of the
roofing product can be increased by increasing the solar heat reflectance of
the
bituminous coating by using the methods described below in combination with
employing infrared-reflective colored roofing granules.
According to a first presently preferred embodiment of the present invention,
infrared-reflective roofing products can be prepared by a method comprising
coating
a fibrous web with a bituminous coating at an elevated temperature to forma
bitumen-coated web; applying at least one powder of an infrared-reflective
material,
such as a pigment or filler, to the bitumen-coated web; and applying roofing
granules
to the bitumen-coated web.
Preferably, to enhance the infrared-reflectance of the surface of the
bituminous
coating, the at least one'powder of the infrared-reflective material can be
directly
deposited onto the surface,of the -bituminous coating after the application of
bituminous
material, and either before the application of roofing granules or after the
application of
roofing granules. The bituminous coating is typically applied to the fibrous
web as a
viscous, tacky, molten liquid material, and the at least one powder of
infrared-reflective.
material is preferably directly deposited on the surface of the bituminous
coating while
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the bituminous material is still warm and tacky, so that the at least one
powder of
infrared-reflective material adheres to the surface of the bitumen-coated web.
Preferably, the at least one powder of infrared-reflective material is applied
to
the surface of the bitumen-coated web at an application rate effective to
increase the
solar heat reflectance of the roofing product by at least about 3 percent, and
more
preferably by at least about 5 percent or more, in comparison with roofing
product that
has not been coated with the at least one powder of infrared-reflective
material.
The at least one infrared-reflective material is preferably applied in powder
form.
Preferably, the powder of the at least one infrared-reflective material has an
average
particle size and particle size distribution such that the gaps between the
roofing
granules deposited on the bitumen-coated web are effectively covered by the
powder
of the at least one infrared-reflective material. Preferably, the powder of
the at least
one infrared-reflective material has an average particle size between about
0.1 micron
and about 250 microns, more preferably between about 0.2 micron and about 100
microns, and even more preferably between about 0.3 micron and 50 microns.
Presently preferred pearlescent pigments have an average particle size of
about 20
microns, while presently preferred titanium dioxide pigments have an average
particle
size in the range from about 0.3 microns to 1 micron. Alternatively, the
preferred
particle size of the at least one infrared-reflective material can be
characterized in terms
of material passing through standard mesh sizes. Thus, it is preferred that
the at least
one infrared-reflective material have a particle size such that the material
pass 60
mesh, more preferably 140 mesh, and still more preferably 270 mesh.
The rate of application of the infrared-reflective material to the bitumen-
coated
web depends upon a variety of factors, including the particle size of the
infrared-
reflective material, the morphology of the infrared-reflective material, et
al. Preferably,
the infrared-reflective material is applied to the surface of the bitumen-
coated web at a
rate sufficient to provide substantial coverage of the surface of the bitumen-
coated web
by the at least one powder of infrared-reflective material. In particular, it
is presently
preferred that the at least one powder of infrared-reflective material be
applied at a rate
sufficient to cover at least about 80 percent of the surface of the bitumen-
coated web,
more preferably, at least about 85 percent of the surface of the bitumen-
coated web,
and yet more preferably at least about 90 percent of the surface of the
bitumen-coated
web, as determined by a suitable technique, depending on the average particle
size of
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the particles. It is particularly preferred that the portion of the surface of
the bitumen-
coated webexposed after the. application-of-roofing granules -has substantial
coverage
by the at least one powder of infrared-reflective material. For example,
particle surface
coverage can be measured using image analysis of optical micrographs, such as
optical micrographs obtained at a magnification of 200X using polarized light
using a
CCD camera ('Sony(D 950MD) and subsequently digitized to a 16-bit gray scale
image
using suitable software, such as Image-ProTM Plus from Media CyberneticsTM,
Inc., Silver
Spring, MD 20910. In this technique, the shingle surface area is recorded in a
black
and white image using a CCD camera fitted to a microscope. The image can then
be
separated into an asphalt coating portion and a granule-covered portion using
the
threshold method in gray scale. The amount of granule coverage can then be
calculated by the image analysis software based upon the number of pixels with
a
gray scale above the threshold level divided by the total number of pixels in
the
image. A similar technique could be employed to determine the amount of
infrared-
reflective material coverage. - Alternatively, when the infrared-reflective
material has
an average particle size below the working range of a light microscope, a
scanning
electron microscope can be used in conjunction with elemental analysis of the
surface area mapped by the SEM to assess surface coverage.
Suitable infrared-reflective materials include, but are not limited to,
titanium
dioxide pigments, nickel titanates, chrome titanates, nano-T102 particles,
light-
interference platelet pigments, pearlescent pigments, metal-oxide coated
substrate
pigments, iron oxide yellow pigments, iron titanium oxides, meta! flakes,-
silica
encapsulated metal flakes, light-scattering pigments, and mirrorized fillers.
Preferably, the infrared-reflective material applied to the surface of bitumen-
coated web should adhere to the surface of the bitumen-coated web, while not
significantly negatively affecting the adhesion of roofing granules to the
bitumen-coated
web or the color or appearance of the finished roofing product.
The at least one powder of infrared-reflective material can be simply dropped
onto the moving surface of the bitumen-coated web before the roofing granules
are
applied to the moving surface. Alternatively, the at least one powder of
infrared-reflective
material can be dropped onto the moving surface of the bitumen-coated web
after the
roofing granules are applied to the moving surface, or after the roofing
granules have
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been pressed into the moving surface to improve adhesion of the roofing
granules to the
bitumen-coated web.
Figure 1 is a schematic illustration of an infrared-reflective roofing product
10
according to the first embodiment of the present invention. The roofing
product 10
comprises a fibrous web 12 coated with a bituminous coating 14 forming a
bitumen-
coated web 16, as well as a coating 20 of at least one powder of an infrared-
reflective
material 22 applied to the bitumen-coated web 16, and roofing granules 26
applied to
the bitumen-coated web 16. In the infrared-roofing product 10 of Fig. 1, the
at least
one powder of an infrared-reflective material 22 has been applied to the
bitumen-
coated web 16 after the roofing granules 26. However, the infrared-reflective
roofing
product 10 of the present invention can also be prepared by applying the at
least one
powder of infrared-reflective material 22 before the roofing granules 26 are
applied to
the bitumen-coated web 16, resulting in the infrared-reflective product 10
shown
schematically in Figure 7, in which some of the particles of the at least one
infrared-
reflective material 22 are to be found under the roofing granules 26.
According to a second presently preferred embodiment of the present
invention, infrared-reflective roofing products can be prepared by a method
comprising coating a fibrous web with a bituminous coating at an elevated
temperature to form a bitumen-coated web; applying a coating material
comprising a
carrier and at least one powder of an infrared-reflective material, such as a
pigment or
filler, to the bitumen-coated web; and applying roofing granules to the
bitumen-coated
web.
Preferably, the coating material has a melting or softening temperature less
than the surface temperature of the bitumen-coated web. More preferably the
melting
temperature of the coating material is about 50 - 150 degrees Centigrade less
than
the surface temperature of the bitumen-coated web. Even more preferably, the
melting temperature of the coating material should have a broad range at least
70 -
100 degrees Centigrade less than the surface temperature of the asphalt. The
coating material thus preferably melts upon application to the bitumen-coated
web,
and is thus distributed upon and adhered to the surface of the bitumen-coated
web.
The coating material is preferably pre-dispersed and includes at least one
infrared-reflective material and a carrier material. The coating material is
preferably a fine
powder that can be deposited on the surface of the bitumen-coated web, or
droplet-
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forming liquid that can be sprayed onto the surface of the bitumen-coated web.
When
the carrier material is solid, the surface of the bitumen-coated web is
preferably
sufficiently hot so that the carrier material melts or at least softens upon
contact with the
bitumen-coated web. The coating material so deposited preferably forms a
continuous
film on the surface of the bitumen-coated web.
The coating material can be applied directly to the surface of the bitumen-
coated
web before application of the roofing granules to the bitumen-coated web. In
the
alternative, when the coating material takes the form of a solid, the coating
material can
be blended with the roofing granules, and the blend of roofing granules and
coating
material can then be applied to the surface of the bitumen-coated web.
Preferably, the coating material will contact the bitumen-coated web when the
bitumen-coated web has a temperature at around 400 - 450 F (204 - 232 C), and
the
carrier will melt or flow to form a thin film on the surface of the bitumen-
coated web to
affix the infrared-reflective material to the bitumen-coated web in order to
enhance the
infrared-reflectance of the roofing product.
As used in the present specification and claims, a "carrier" for the at least
one
powder can be liquid or solid, a film or a particulate, a polymer, or an
organic solvent
or water, or a solvent or water-borne coating.
Examples of carrier materials include thermoplastic polymeric materials having
a
suitable glass or crystalline transition temperature such as disclosed, for
example, in D.
W. Van Krevelen et al., Properties of Polymers, Correlations with Chemical
Structure
(Elsevier Publishing Company, New York, 1972). Suitable thermoplastic
materials
include poly(meth)acrylates having an appropriate monomer composition
including
acrylic homopolymers such as poly ethyl acrylate, poly isohexyl acrylate, and
poly n-butyl
acrylate, copolymers of ethyl acrylate and methyl methacrylate, copolymers of
ethyl
acrylate, butyl acrylate and methyl methacrylate, copolymers of ethyl
acrylate, n-butyl
acrylate and methacrylic acid, copolymers of methyl methacrylate, ethyl
acrylate and
acrylic acid, copolymers of ethyl acrylate, n-butyl acrylate, styrene, and
acrylic acid, and
the like; polyolefins such as, polyethylene, polypropylene, and polybutylene;
olefinic
copolymers such as copolymers of ethylene and vinyl acetate, copolymers of
ethylene
and ethyl acrylate, copolymers of ethylene and acrylic acid, copolymers of
ethylene and
methacrylic acid, copolymers of ethylene, vinyl acetate and acrylic acid, and
the like;
ethylene propylene diene monomer copolymers; block copolymers such as styrene-
CA 02491294 2004-12-30
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butadiene-styrene-butadiene triblock copolymer, styrene-isoprene-styrene
triblock
copolymer, ionomers such as ethylene methyl methacrylic acid ionically
crosslinked
ionomers, polyurethanes, polysiloxanes, et al. Further blends of polymeric
materials can
be employed. Preferably, the monomer composition is selected to provide the
desired
melting or softening properties to the polymeric carrier material. Preferably,
the carrier
material comprises a thermoplastic polymeric material having excellent
resistance to
degradation by exposure to ultraviolet radiation, and, in particular, acrylic
polymeric
materials are especially preferred for their superior ultraviolet resistance.
The carrier
material can also include suitable plasticizers, reactive diluents, and the
like to adjust the
effective melting temperature of the polymeric material, as well as tackifying
resins such
as aromatic modified hydrocarbon resins and similar modifiers to increase the
adhesion
of the carrier material. In addition, the carrier material can include
surfactants, pigment
dispersants, and the like, to aid in dispersing the particles of the infrared-
reflective
pigment, granulating aids to aid in the preparation of appropriately-sized
particles, flow
and rheology modifiers to enhance application properties, and like additives.
The carrier material is preferably formulated to be sufficiently hydrophobic
to
resist weather-driven exposure to moisture. Thus, natural and synthetic waxes
including
paraffin can also be used as a carrier material.
The coating material can also include additives, such as algaecides, impact
modifiers, UV stabilizers, and/or crack-healing agents, to introduce
additional
functionalities to the asphalt shingles, such as, for example, algae-
resistance, impact
resistance, or better durability.
A method of improving adhesion between roofing granules and asphalt coating
using non-asphalt adhesives or a thermoplastic adhesive interface by spraying
onto hot
asphalt surface prior to granule drops has been disclosed in U.S. Patents
5,380,552 and
5,516,573. Preferably, such an adhesive is modified for use in the present
invention by
including at least one infrared-reflective material.
Figure 2 is a schematic illustration of an infrared-reflective roofing product
30
according to the second embodiment of the present invention. The roofing
product
30 comprises a fibrous web 32 coated with a bituminous coating 34 forming a
bitumen-coated web 36, as well as a coating material 40 including a carrier 42
and at
least one powder of an infrared-reflective material 44 applied to the bitumen-
coated
web 36, and roofing granules 46 applied to the bitumen-coated web 36.
CA 02491294 2004-12-30
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According to a third presently preferred embodiment of the present invention,
infrared-reflective roofing products can be prepared by a method comprising
coating
a fibrous web with a bituminous coating at an elevated temperature to form a
bitumen-coated web; applying a coating film comprising a film carrier and at
least one
powder of an infrared-reflective material, such as a pigment or filler, to the
bitumen-
coated web; and applying roofing granules to the bitumen-coated web.
Preferably,
the coating film is directly laminated onto the bitumen-coated web.
Preferably, the
coating film is directly laminated to bitumen-coated web while the bitumen-
coated
web is at an elevated temperature sufficient to at least partially fuse the
film carrier to
help adhere the coating film to the bitumen-coated web.
Preferably, adherence of the coating film to the bitumen-coated carrier does
not
significantly negatively affect adherence of the roofing granules to the
bitumen-coated
web.
The coating film can be applied as a film, as a liquid that solidifies to
become
a film, or as a liquid that contains components that form a film after
application.
Examples of materials suitable for use as a film carrier include thermoplastic
materials such as discussed in reference to the second presently preferred
embodiment
of the process of the present invention.
Preferably, the coating film has sufficient thickness and mechanical strength
to
ensure facile handling and mechanical application of the film. Preferably, the
coating film
has a thickness of from about 20 to 250. microns, more preferably from about
20 to 200
microns, and even more preferably from about 25 to 150 microns. Overly thick
films are
to be avoided, in that they can pose handling, draping and heat transfer
problems in
application. It is preferred that the weight percentage of the at least one
powder of
infrared-reflective material to film carrier in the coating film be from about
2 to about 60
percent, more preferably from about 5 to about 40 percent, and still more
preferably from
about 10 to 35 percent.
Additives can be'included in the coating film to introduce additional
functionalities
to the finished roofing prodpct. Examples of such additives include
algaecides, impact
modifiers, UV stabilizers, and/or crack-healing agents, to introduce
additional
functionalities to the asphalt shingles, such as, for example, algae-
resistance, impact
resistance, or better durability. In addition, additives can be employed to
enhance the
properties of the coating film, such as solvents, plasticizers and tackifiers,
flow modifiers,
CA 02491294 2012-03-14
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and adhesion promoters. The surface of the coating film can be optionally
coated with a
suitable lamination adhesive.
Figure 3 is a schematic illustration of an infrared-reflective roofing product
50
according to the third embodiment of the present invention. The roofing
product 50
comprises a fibrous web 52 coated with a bituminous coating 54 forming a
bitumen-
coated web 56, as well as a coating film 60 including a film carrier 62 and at
least one
powder of an infrared-reflective material 64 applied to the bitumen-coated web
56,
and roofing granules 66 applied to the bitumen-coated web 56.
According to a fourth presently preferred embodiment of the present invention,
infrared-reflective roofing products can be prepared by a method comprising
coating
a fibrous web with a bituminous coating at an elevated temperature to form a
bitumen-coated web; applying a coating web comprising a web carrier, at least
one
powder of an infrared-reflective material, such as a pigment or filler, and
roofing
granules, to the bitumen-coated web. Preferably, the coating web.is directly
laminated onto the bitumen-coated web. Preferably, the coating web is directly
laminated to bitumen-coated web while the bitumen-coated web is at an elevated
temperature sufficient-to at least partially fuse the web carrier to help
adhere the
coating film to the bitumen-coated web.
The web carrier holding the-roofing granules together should have sufficient
modulus and the ability to withstand the temperatures of hot bituminous
coating without
disintegration, while adhering to and covering the bitumen-coated web
resulting in higher
solar reflectance. An example of a suitable web carrier is disclosed in U.S.
Patent
Application Publication No. 2002/0160151M.,
Figure 4 is a schematic illustration of an infrared-reflective, deep-tone
roofing
product 70 according to the fourth embodiment of the present invention. The
roofing
product 70 comprises a fibrous web 72 coated with a bituminous coating 74
forming a
bitumen-coated web 76, as well as a coating web 80 including a web carrier 82,
at
least one powder of an infrared-reflective material 84, and roofing granules
86,
applied to the bitumen-coated web 76.
According to a fifth presently preferred embodiment of the present invention,
infrared-reflective roofing products can be prepared by a method comprising
coating
a fibrous web with a bituminous coating at an elevated temperature to form a
bitumen-coated web; applying roofing granules to the bitumen-coated web to
form an
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intermediate product, and then applying a coating film to the intermediate
product.
The coating film comprises a film carrier and at least one powder of an
infrared-
reflective material, such as a pigment or filler. Preferably, the coating web
is a
coating film that is directly laminated onto the bitumen-coated web.
Preferably, the
coating web is directly laminated to intermediate product while the
intermediate
product is at an elevated temperature sufficient to at least partially fuse
the web
carrier to help adhere the coating film to the intermediate product.
This fifth embodiment of the present invention provides yet another method to
increase the solar reflectance of shingles with L*<60 to above 25%.
The coating film or adhesive containing the at least one infrared-reflective
material is preferably laminated directly onto the surface of otherwise
completely
constructed roofing product or intermediate material, preferably before the
material is cut
to size to form, for example, roofing shingles.
The film carrier is preferably a thin film, with a thickness of from about 20
to about
250 microns, more preferably from about 25 to about 150 microns.
The film carrier preferably has the ability to conform to the irregular,
granular
surface of the roofing product or shingle, or has the ability to adhere to the
roofing
product surface by either thermal setting or other suitable means.
Although such film carriers bearing infrared-reflective materials may be
colored, it
is more desirable to employ a transparent or semi-transparent film carrier
that has
increased infrared-reflectance by using transparent infrared-reflective
pigments, such as
for example, light-interference platelet pigments or nano-Ti02 particles. As
used in the
present specification and claims, transparency is determined in terms of the
opacity of
the material, and "transparent" means having a contrast ratio of less than
about 30
percent, while "semi-transparent" means contrast ration of less than about 80
percent.
The contrast ratio is measured by. applying a coating or mounting a film of
the specimen
material over a Leneta BW chart and measuring the color, and calculating the
ratio of L*
of the coating or film over the black substrate divided by L* of the coating
or film over the
white substrate, and expressing-the ratio as a percentage of the L* measured
for the
white substrate. A coating having a higher contrast ratio, or hiding power, is
more
opaque, while a lower contrast ratio is more transparent. Thus, a coating
having the
same L* measurement over both the black and white substrates would have a
contrast
ratio of 100%, and would be opaque or non-transparent.
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Figure 5 is a schematic illustration of an infrared-reflective roofing product
90
according to the fifth embodiment of the present invention. The roofing
product 90
comprises a fibrous web 92 coated with a bituminous coating 94 forming a
bitumen-
coated web 96, and roofing granules 106 embedded in the bitumen-coated web 96
to
form an intermediate product 98, as well as a coating film 100 including a
film carrier
102, and at least one powder of an infrared-reflective material 104, applied
to the
intermediate product 98.
According to a sixth presently preferred embodiment of the present invention,
infrared-reflective roofing products can be prepared by a method comprising
coating
a fibrous web with a bituminous coating at an elevated temperature to form a
bitumen-coated web; applying roofing granules to the bitumen-coated web to
form an
intermediate product, and then applying a coating fluid to the intermediate
product.
The coating fluid comprises a fluid carrier and at least one powder of an
infrared-
reflective material, such as a pigment or filler. Preferably, the coating
fluid is applied
by spraying the coating fluid directly onto the bitumen-coated web.
Preferably, the
coating fluid is directly applied to intermediate product while the
intermediate product
is at an elevated temperature sufficient to help adhere the coating fluid to
the
intermediate product.
This sixth embodiment provides yet another method to increase the solar heat
reflectance of a shingle with L*<60.
The coating fluid or adhesive can have desirable colors to achieve aesthetic
values,. or can be transparent or semitransparent in the visible spectrum when
cured to
reveal the actual shingle colors.
Examples of fluid carriers that can be employed in the process of the present
invention include aqueous emulsions of synthetic polymers, such as aqueous
emulsions
of acrylic polymers, such as emulsion copolymers of (meth)acrylic esters,
amides and
acids. For example, emulsion copolymers of ethyl acrylate, butyl acrylate,
methylmethacrylate and acrylic acid can be employed. Polymers having good
exterior
weathering properties, such as the acrylic polymers and copolymers are
preferred.
Solvent based synthetic polymers, such as organic solvent based (meth)acrylic
copolymers, can also be employed as fluid carriers in the process of the
present
invention. One hundred percent-solids two-part reactive coatings could also be
used,
such as coatings based on polyurethanes, polyureas and polyepoxides. Examples
of
CA 02491294 2004-12-30
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polyurea-type reactive coatings, based on aspartic acid ester ureas, are
disclosed in U.S.
Patent 6,451,874. Examples of two-part reactive epoxy systems cured with an
amine-
free SbF5 alcohol complex are disclosed in U.S. Patent 5,731,369.
The coating fluid can also include conventional coatings adjuvants and
additives.
The coating fluid can be water-based or solvent-based, or alternatively,
substantially free
of solvents. Water-based coating fluids can include, for example, water,
cosolvents,
dispersants, emulsifiers, coloring materials, preservatives, coalescents, and
the like. In
the case of water-based coating fluids, such water-based coating fluids have
total solids
of from about 10 to about 70 percent by weight, and more preferably from about
30 to
about 60 percent by weight. In the case of solvent-based coating fluids, such
solid-based
coating fluids have total solids of at least about 50 percent by weight, more
preferably at
least about 70 percent by weight, and even more preferably are substantially
free of
solvents. Preferably, the coating fluids have a volatile organic content (VOC)
of less than
about 450 g/L, more preferably less than about 250 g/L, and even more
preferably less
than about 100 g/L VOC as applied.
Other additives can also be incorporated into the coating fluid to add
desirable
functionalities to the finished roofing product. Examples of such other
additives include
but are not limited to plasticizers, wetting agents, coalescing agents, and
flow modifiers.
Figure 6 is a schematic illustration of an infrared-reflective roofing product
110
according to the sixth embodiment of the present invention. The roofing
product 110
comprises a fibrous web 112 coated with a bituminous coating 114 forming a
bitumen-coated web 116, and roofing granules 126 embedded in the bitumen-
coated
web 116 to form an intermediate product 118, as well as a coating fluid 120
including
a fluid carrier 122, and at least one powder of an infrared-reflective
material 124,
applied to the intermediate product 118.
The above-referenced presently preferred embodiments of the method of the
present invention provide infrared-reflective material on the surface of the
roofing
product in between those portions of the surface of the roofing product which
are
covered by roofing granules. Preferably, the above-referenced methods of the
present
invention provide infrared-reflective material to cover at least about 75
percent of the
surface area of the roofing product not otherwise covered by roofing granules,
more
preferably at least about 90 percent, and even more preferably at least about
95
percent. Thus, for example, if roofing granules cover about 85 percent of the
surface
CA 02491294 2004-12-30
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area of the mineral product, it is preferred that the above-described methods
of the
present invention provide infrared-reflective material over at least about 75
percent of
the remaining 15 percent of the surface area of the roofing product.
According to a seventh presently preferred embodiment of the present
invention, infrared-reflective roofing products can be prepared by a method
comprising coating a fibrous web with a bituminous coating at an elevated
temperature to form a bitumen-coated web; applying roofing granules to the
bitumen-
coated web, the roofing granules including (a) at least 50 percent by weight
off-white
mineral particles comprising A1203 and SiO2, preferably having a weight ratio
of A1203
to S102 from about 0.2:1 to about 1:1, and more preferably having a weight
ratio of
A203 to S102 from about 0.7:1 to about 0.9:1, and having a solar reflectance
greater
than 30 percent while having and L* of less than about 60 percent, and (b)
mineral
particles selected from the group consisting of conventional colored roofing
granules,
and infrared-reflective roofing granules. The two types of mineral particles
can be
blended in combinations to generate desired colors. The blended mineral
granules
can be directly applied to the hot bituminous coating to form the shingle.
In this embodiment, it is important that the aluminum oxide content be less
than that of silicon dioxide in order that the granules have an off-white
color. If
aluminum content becomes too high, the particles become white in color. Higher
alumina content is also accompanied by increase in hardness that can
negatively
impact on the wear of machinery and cutters. The desired mineral granules can
be
obtained from commercially available refractory grog (available form Maryland
Refractories Co., Irondale, OH) or from crushed natural feldspar rocks (for
example,
medium chip feldspar from Pacer Corp., Custer, South Dakota, which has solar
reflectivity of 53%).
Figure 8 is a schematic illustration of an infrared-reflective roofing product
130
according to the seventh embodiment of the present invention. The roofing
product
130 comprises a fibrous web 132 coated with a bituminous coating 134 forming a
bitumen-coated web 136, and conventional roofing granules 140 as well as off-
white
mineral particles 142 embedded in the bitumen-coated web 136. The roofing
product
130 may also optionally include at least one powder of an infrared-reflective
material
(not shown) within the construction of the roofing product 130.
CA 02491294 2004-12-30
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Examples of near IR-reflective pigments available from the Shepherd Color
Company, Cincinnati, OH, include Arctic Black 10C909 (chromium green-black),
Black 411 (chromium iron oxide), Brown 12 (zinc iron chromite), Brown 8 (iron
titanium brown spinel), and Yellow 193 (chrome antimony titanium).
Light-interference platelet pigments are known to give rise to various optical
effects when incorporated in coatings, including opalescence or "ppareescence.
Surprisingly, light-interference platelet pigments have been found to provide
or
enhance infrared-reflectance of roofing granules coated with compositions
including
such pigments. Also surprisingly, roofing products incorporating light-
interference
platelet pigments have been found to have enhanced infrared-reflectance when
such
pigments are included in other parts of a roofing product construction.
Examples of light-interference platelet pigments that can be employed in the
process of the present invention include pigments available from Wenzhou
Pearlescent Pigments Co., Ltd., No. 9 Small East District, Wenzhou Economical
and
Technical Development Zone, Peoples Republic of China, such as Taizhu TZ5013
(mica, rutile titanium dioxide and iron oxide, golden color), TZ5012 (mica,
rutile
titanium dioxide and iron oxide, golden color), TZ4013 (mica and iron oxide,
wine red
color), TZ4012 (mica and iron oxide, red brown color), TZ4011 (mica and iron
oxide,
bronze color), TZ2015 (mica and rutile titanium dioxide, interference green
color),
TZ2014 (mica and rutile titanium dioxide, interference blue color), TZ2013
(mica and
rutile titanium dioxide, interference violet color), TZ2012 (mica and rutile
titanium
dioxide, interference red color), TZ2011 (mica and rutile titanium dioxide,
interference
golden color), TZ1 222 (mica and rutile titanium dioxide, silver white color),
TZ1 004
(mica and anatase titanium dioxide, silver white color), TZ4001/600 (mica and
iron
oxide, bronze appearance), TZ5003/600 (mica, titanium oxide and iron oxide,
gold
appearance), TZ1001/80 (mica and titanium dioxide, off-white appearance),
TZ2001/600 (mica, titanium dioxide, tin oxide, off-white/gold appearance),
TZ2004/600 (mica, titanium dioxide, tin oxide, off-white/blue appearance),
TZ2005/600 (mica, titanium dioxide, tin oxide, off-white/green appearance),
and
TZ4002/600 (mica and iron oxide, bronze appearance).
Examples of light-interference platelet pigments that can be employed in the
process of the present invention also include pigments available from Merck
KGaA,
Darmstadt, Germany, such as Iriodin pearlescent pigment based on mica covered
CA 02491294 2012-03-14
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with a thin layer of titanium dioxide and/or iron oxide; Xirallic TM high
chroma crystal
effect pigment based upon A1203 platelets coated with metal oxides, including
Xirallic
T 60-10 WNT crystal silver, Xirallic T 60-20 WNT sunbeam gold, and Xirallic F
60-50
WNT fireside copper; ColorStream TM multi color effect pigments based on Si02
platelets coated with metal oxides, including ColorStream F 20-00 WNT autumn
mystery and ColorStream F 20-07 WNT viola fantasy; and ultra
interference.pigments
based on Ti02 and mica.
Examples of mirrorized silica pigments that can be employed in the process of
the present invention include pigments such as Chrom BriteTM CB4500, available
from Bead Brite, 400 Oser Ave, Suite 600, Hauppauge, N.Y. 11788.
The infrared-reflective roofing shingles of the present invention can include
roofing granules, powders, coatings or films including conventional coatings
pigments. Examples of coatings pigments that can be used include those
provided
by the Color Division of Ferro Corporation, 4150 East 56th St., Cleveland, OH
44101,
and produced using high temperature calcinations, including PC-9415 Yellow, PC-
9416 Yellow, PC-9158 Autumn Gold, PC-9189 Bright Golden Yellow, V-9186 Iron-
Free Chestnut Brown, V-780 Black, V0797 IR Black, V-9248 Blue, PC-9250 Bright
Blue, PC-5686 Turquoise, V-13810 Red, V-12600 Camouflage Green, V12560 IR
Green, V-778 IR Black, and V-799 Black. Further examples of coatings. pigments
that
can be used include white titanium dioxide pigments provided by Du Pont de
NemoursTM, P.O. Box-8070, Wilmington, DE 19880.
The present invention provides mineral-surfaced roofing products including
asphalt shingles, with CIE L* less than 85, more preferably less than about
55, and
even more preferably less than about 45, and solar reflectance greater than
25%.
Preferably, roofing products, such as asphalt shingles, according to the
present
invention comprise colored, infrared-reflective granules according to the
present
invention, and optionally, conventional colored roofing granules. Conventional
colored roofing granules and infrared-reflective roofing granules can be
blended in
combinations to generate desirable colors. As noted above, in some of the
embodiments of the present invention, the blend of granules can be then
directly
applied on to hot bituminous coating to form the roofing product. Examples of
granule deposition apparatus that can be employed to manufacture roofing
products,
including asphalt shingles, according to the present invention are provided,
for
CA 02491294 2012-03-14
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example, in U.S. Patents 4,583,486, 5,795,389, and 6,610,147, and U.S. Patent
Application Publication U.S. 2002/0092596.
The process of the present invention advantageously permits the solar
reflectance of the roofing products such as shingles employing the solar-
reflective
granules, powders, coatings or films to be tailored to achieve specific color
effects.,
The colored, infrared-reflective roofing products of the present invention,
such as colored infrared-reflective roofing shingles, can be manufactured
using
conventional roofing production processes. Typically, bituminous roofing
products
are sheet goods that include a non-woven base or scrim formed of a fibrous
material, such as a glass fiber scrim. The base is coated with one or more
layers of
a bituminous material such as asphalt to provide water and weather resistance
to the
roofing product. One side of the roofing product is typically coated with
mineral
granules to provide durability, reflect heat and solar radiation, and to
protect the
bituminous binder from environmental degradation. In the present invention,
colored, infrared-reflective granules can be mixed with conventional roofing
granules, and the granule mixture can be embedded in the surface of such
bituminous roofing products using conventional methods. Alternatively,
colored,
infrared-reflective granules can be substituted for conventional roofing
granules in
manufacture of bituminous roofing products to provide those roofing products
with
solar reflectance.
Bituminous roofing products are typically manufactured in continuous
processes in which a continuous substrate sheet of a fibrous material such as
a
continuous felt sheet or glass fiber mat is immersed in a bath of hot, fluid
bituminous
coating material so that.the bituminous material saturates the substrate sheet
and
coats at least one side of the, substrate. The reverse side of the substrate
sheet can
be coated with an anti-stick material such as a suitable mineral powder or a
fine
sand. Roofing granules are then distributed over selected portions of the top
of the
sheet, and the bituminous material serves as an adhesive to bind the roofing
granules to the sheet when the -bituminous material has cooled. The sheet can
then
be cut into conventional shingle sizes and shapes (such as one foot by three
feet
rectangles), slots can be cut in the shingles to provide a plurality of "tabs"
for ease of
installation or for aesthetic effects, additional bituminous adhesive can be
applied in
strategic locations and covered with release paper to provide for securing
CA 02491294 2004-12-30
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successive courses of shingles during roof installation, and the finished
shingles can
be packaged. More complex methods of shingle construction can also be
employed,
such as building up multiple layers of sheet in selected portions of the
shingle to
provide an enhanced visual appearance, or to simulate other types of roofing
products. Alternatively, the sheet can be formed into membranes or roll goods
for
commercial or industrial roofing applications.
The bituminous material used in manufacturing roofing products according to
the present invention is derived from a petroleum-processing by-product such
as
pitch, "straight-run" bitumen, or "blown" bitumen. The bituminous material can
be
modified with extender materials such as oils, petroleum extracts, and/or
petroleum
residues. The bituminous material can include various modifying ingredients
such as
polymeric materials such as, for example, SBS (styrene-butadiene-styrene)
block
copolymers, resins, flame-retardant materials, oils, stabilizing materials,
anti-static
compounds, and the like. Preferably, the total amount by weight of such
modifying
ingredients is not more than about 15 percent of the total weight of the
bituminous
material. The bituminous material can also include amorphous polyolefins, up
to
about 25 percent by weight. Examples of suitable amorphous polyolefins include
atactic polypropylene, ethylene-propylene rubber, etc. Preferably, the
amorphous
polyolefins employed have a softening point of from about 130 degrees C to
about
160 degrees C. The bituminous composition can also include a suitable filler,
such
as calcium carbonate, talc, carbon black, stone dust, or fly ash, preferably
in an
amount from about 10 percent to 70 percent by weight of the bituminous
composite
material. -
The following examples are provided to better disclose and teach processes
and compositions of the present invention. They are for illustrative purposes
only,
and it must be acknowledged that minor variations and changes can be made
without
materially affecting the spirit and scope of the invention as recited in the
claims that
follow.
Examplel
Asphalt panels about 4"x4"x1/8" thick were prepared on an aluminum backing by
using coating grade asphalt from a Venezuelan crude source and filled with 63
wt%
calcium carbonate fillers to achieve viscosity of 2600 cps at 400 F. The
resultant asphalt
panel has only 5.2% solar heat reflectance as measured by the ASTM C1549
method
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using a portable solar reflectometer (Model SSR-E from Devices & Services,
Dallas, TX).
To increase the solar reflectance of the asphalt coating, a fine powder of a
pearlescent
pigment (TZ1 004 available from Global Pigments, LLC, White Plain, New York),
was
deposited on the molten surface of asphalt coating by dusting the pigment
through a U.S.
#40 mesh filter. The resultant panel with pearlescent-pigmented surface had a
very
desirable black color, comparable to original asphalt coating, and a high
solar reflectance
of 39.5%.
Example 2
An asphalt coating sample was first prepared by mixing 226.3 gm of roofing-
grade asphalt with 420.3 gm of limestone filler (Global Stone, from James
River, Inc.,
Buchanan, VA) at 400 F (204 degrees Centigrade) to a uniform mixture. The hot,
molten
asphalt coating was then gently poured onto a 4"x1 2"x0.025" (10.16 cm x 30.48
cm x
0.0635 cm) aluminum panel to form a sheet about 1/8" (0.3175 cm) thick. Upon
cooling to
a surface temperature of around 350 F (177 degrees Centigrade), roofing
granules
having #68 buff color (available from CertainTeed Corp., Norwood, MA) were
evenly
dropped onto the hot asphalt to completely covered the surface. The surface
was then
pressed by using a 27 lb (12.25 kg) roller back and forth to embed the
granules into the
coating. The excess granules were removed from the surface by inverting the
panel
followed by gentle tapping. One panel, designated as a control, was then set
aside to
cool. Another panel sample was immediately placed under an infrared heat lamp
to keep
the surface temperature at around 250 F (121 degrees Centigrade) and then an
infrared-
functional pigment (9G1302 pearlescent pigment from Engelhard Corp., Iselin,
NJ) was
evenly deposited through a #50-mesh filter onto the surface to cover the
exposed asphalt
coating between the roofing granules. The panel was then removed from the heat
source to cool. After cooling, excess infrared-functional pigment was vacuumed
from.the
surface for recycling.
The control sample panel had a regular shingle surface appearance with the
solar
reflectance of 23.4% (measured according to ASTM C1371 method) and HunterLab
color reading of L*=52.68, a*=6.67, and b*=19.45, whereas the sample panel
with
infrared-functional pigment had an increased solar reflectance of 25.3% and a
similar
color of L*=55.52, a*=5.18, and b*=16.09.
Example 3
{ CA 02491294 2012-03-14
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Two shingle panel samples were prepared. An asphalt-coating sample was
prepared by mixing 114.2 gm of roofing-grade asphalt from a Venezuelan crude
with
212.1 gm of limestone filler at 400 F (204 degrees Centigrade) to a uniform
mixture. The
hot, molten asphalt coating was then gently poured onto a 4"x12"x0.025" (10.16
cm x
30.48 cm x 0.0635 cm) aluminum panel to form a sheet about 1/8"(0.3175 cm)
thick.
One sample panel was then prepared as a control by applying #68.colored
roofing
granules (commercially available from CertainTeed Corp., Norwood, MA) at the
surface
temperature about 350 F (177 degrees Centigrade) followed by pressing under a
27 lb
(12.25 kg) roller as described in Example 2. For the second panel sample, a
second
coating containing infrared-reflective material, a white acrylic powder
pigmented with TiO2
as an infrared-reflective material (Ultra Detail, available from Mark
Enterprises, Anaheim,
CA), having a melting temperature of 300-325 F (149-163 degrees Centigrade)
was
applied immediately after the pouring of the asphalt coating with while the
surface
temperature was greater than 375 F (191 degrees Centigrade). Upon contacting
the hot
asphalt surface, the acrylic powder melted to form a continuous, uniform white
reflective
surface. While keeping the surface of the coated asphalt panel surface hot at
350 F (177
degrees Centigrade) under a heat lamp, the same #68 colored roofing granules
were
applied onto the surface followed by pressing using a 27 lb (12.25 kg) roller
to achieve a
shingle surface appearance. Excess granules were removed from the surface by
inverting. the panel and tapping gently to shake them off. The sample panel
was then
allowed to cool in room temperature.
The resultant sample panel with the white acrylic coating between roofing
granules had improved solar reflectance of 27.3% and a similar color reading
of
L*=55.27, a*=5.58, and b*=16.14, as compared to the control panel of solar
reflectance at
23.4% and color reading of L*=52.68, a*=6.67, b*=19.43.
Example 4
Another example of shingle surface with increased solar reflectance was
prepared by first preparing an integrated sheet containing roofing granules
and an acrylic
binder followed by lamination onto a hot asphalt coating to form the product.
The
integrated sheet was prepared by applying a TiO2 pigmented, exterior grade
acrylic
coating (ARM3640-1B available from Rohm & HaasTM Corp., Spring House, PA) at a
thickness of 10 mil onto'a silicone release paper using a stainless steel
drawdown bar
(part # SAR-5310 from BYK Gardner T"^, Columbia, MD). Roofing granules having
a #68
CA 02491294 2012-03-14
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buff color (available from CertainTeed Corp., Norwood, MA) were then applied
onto the
coating to completely cover the surface followed by pressing using a 27 lb
(12.25 kg)
roller. The sheet was then allowed to dry under ambient laboratory conditions
to achieve
the strength of the binder. The sheet was then removed from the release paper
by rolling
up as a pre-fabricated roll of integrated sheet. The integrated sheet was then
laminated
onto a hot asphalt coating containing 35% roofing-grade asphalt and 65%
limestone filler
by unrolling the integrated sheet. The lamination process was carried out at
an asphalt
surface temperature of 250-280 F (121-138 degrees Centigrade) to avoid heat
degradation of the acrylic binder. The resultant shingle had a'solar
reflectance of 25.0%
and color reading of L*=54.55, a*=6.37, and b*=1 9.37, as compared to a
control with the
same colored granules in asphalt coating (see Example 2) having solar
reflectance of -
23.4% and color reading of L*=52.68, a*=6.67, b*=19.43.
Example 5
An exterior grade coating suitable for spraying by a spray gun was prepared by
mixing 50 g of acrylic coating (RhoplexTM E-2000, Rohm and HaasTM Corp.,
Springfield, PA) an
6.4 g of light-interference platelet pigments of TZ4002 (Global Pigments, LLC,
White
Plains, NY). The coating was then sprayed at air pressure of 67psi onto the
surface of a
commercially available asphalt shingles (XT25 Star White, CertainTeed ,
Oxford, NC) to
form a uniform coating. The resultant shingle had a desirable copper gold
finish with L* _
44.70; a* = 20.37, b* = 18.29, and a high solar reflectance of 25.3%, as
measured by the
ASTM C1549 method. A comparison of the CIE color parameters and solar.
reflectance
of this shingle with a commercial_asphalt shingle with similar colors, a
conventional white
asphalt shingle, and a white-asphalt shingle coated with a spray-on acrylic
coating is
provided in Table A below. These results show that the shingle of the present
invention
has deep-tone color properties similar to that of the commercial deep-tone
shingle, but
substantially improved solar reflectance.
Table A
Sample CIE Color Parameters . Solar
%
Information L* a* b* Reflectance,
White asphalt shingle 62.91 -0.55 3.73 28.7
.-= . ~ CA 02491294 2012-03-14
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White asphalt shingle with a spray- 61.9 -0.63 2.82 28.2
on, clear acrylic coating
Example 5 (White asphalt shingle 44.70 20.37 18.29 25.3
with a spray-on, pigmented acrylic
coating)
Commercial asphalt shingle with 48.00 6.93 19.05 18.9
comparable colors to Example 5
Example 6
An asphalt shingle panel was prepared by first pouring an approximately 1/8"
thick asphalt coating comprising a mixture of 35% of roofing grade asphalt and
65% by
weight of calcium carbonate filler onto an aluminum panel. The coating panel
was
heated using a hot stage heater so that the asphalt remained molten, and an
excess of
mineral granules comprising of 80% refractory grog having particle size
between #8 and
#20 mesh (Heavy Duty 8/20 from Maryland Refractories Co., Irondale, OH) and
20% of
dark brown #41 granules (commercially available from CertainTeed Corp.,
Norwood, MA)
was deposited on the onto the surface of molten asphalt.. The granules were
then
pressed by using a 27 lb (12.25 kg) roller to result in a smooth surface. The
resultant
shingle panel had a "wood blend" appearance with color reading of L*=56.52,
a*=3.78,
b*=13.61 as measured by HunterLab colorimeter, and a solar reflectance of 35%
as
measured by using a portable solar reflectometer (Model SSR-E from Devices &
Services, Dallas, TX).
