Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: PLASTIC ROOF TILES
FIELD OF THE INVENTION
The present invention is directed to shaped plastic
roof tiles, particularly those shaped to have the
appearance of slate tiles and the process for manufacturing
the tiles.
BACKGROUND OF THE INVENTION
There are many different roofing materials presently
in use including wood shakes and shingles, asphalt
shingles, clay tiles, metal panels and slate tiles. While
asphalt shingles are the most commonly utilized because of
their lower cost and weight, other materials are more
preferred for their aesthetic appeal. Amongst such
materials, clay and slate are particularly desirable for
their longevity and appearance. Clay and slate do however
have drawbacks. There is only a limited supply of slate
which makes it very expensive as a roofing material. In
addition, clay and slate are extremely heavy materials
requiring that the roof on which they are to be installed
be specially engineered to support the weight, which also
increases the cost of the finished roof.
There have been attempts to construct tiles of plastic
material having the appearance of clay and slate but which
do not have some of the drawbacks. Such plastic tiles are
of relatively low weight and generally do not require a
specially engineered roof, being able to be installed on
standard roof construction. Plastic also has an advantage
of being able to be formulated to have a long life.
Examples of such plastic tiles are described in US Patents
5,992,116; 5,946,877; 5,630,305; 5,615,523 and 5,295,339
among others.
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There still remains a need for an economical to
manufacture shaped plastic roof tiles having the appearance
of more expensive roofing materials such as slate.
SUMMARY OF THE INVENTION
The present invention is directed to a shaped plastic
roof tile. The tile is constructed of the combination of a
thermoplastic and a chlorine containing polymer in an
amount to provide a final chlorine content to the tile of
between about 1% and about 65% by weight based upon the
total weight of the tile.
In an aspect of the invention, the thermoplastic is a
polyolefin.
In another aspect of the invention, the polyolefin
polymer is a combination of polyethylene and polypropylene
derived from recycled material.
In yet another aspect of the invention, the chlorine
containing polymer is one or more polymers selected from
the group consisting of polyvinyl chloride (PVC),
chlorinated polyvinyl chloride (CPVC), polyvinylidene
dichloride (PVDC), chlorinated polyolefin, acrylate
modified PVC, neoprene rubber, copolymers of vinyl chloride
with ethylene, propylene, vinyl acetate, vinyl dichloride,
and butadiene, copolymers of vinylidene chloride with butyl
acrylate and nitrile, and polymer blends of PVC with
acrylonitrile-butadiene-styrene (ABS), acrylic-styrene-
acrylonitrile (ASA), nitrile rubber, and polyvinyl acetate
(EVA).
In yet another aspect of the invention, the chlorine
containing polymer is recycled neoprene rubber.
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BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention is
illustrated in the attached drawings in which:
Figure 1 is a top plan view of a plastic slate-like
tile of the present invention;
Figure 2 is a top plan view of the tile of Figure 1
being installed on a roof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of a plastic roof tile of the
present invention is illustrated in the attached figures
generally indicated by the numeral 10. The roof tile is
sized approximately equal to that of traditional slate
tiles having a width of approximately 12 inches and a total
height of approximately 18 inches. The bottom portion 12
of the roof tile 10 has a slightly reduced width relative
to the top portion of the roof tile 10 to provide for the
proper reveal for the esthetic appearance of the tile 10
once it is installed on the roof. This bottom portion 12
of the roof tile is also provided with a slate like
appearance by texturing the surface of the roof tile to
provide for the appearance of slate. The reduced width
bottom portion 12 extends upwardly approximately 6 inches
from the bottom of the tile and the slate texture extends
upwardly to approximately half of the height of the plastic
tile 10. The plastic tile 10 is provided with guide marks
14 on either side to allow for proper alignment of the tile
10 and thereby provide for the proper reveal of the tile
10 as desired. Traditionally slate tiles are laid with
either a 6 or 7 inch reveal and rule markings are provided
on either side of the tile 6 to 7 inches down from the top
edge of the tile. The use of these markings will be
explained below.
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The tile 10 is also preferably provided with one or
more fastening guides 16 to indicate to the installer the
proper location for the fasteners for attaching the roof
tile to the roof surface. Preferably the tile is attached
to the roof surface with suitable nails and nailing points
are provided on either side of the tile in the proper
position for a 6 or 7 inch reveal of the tile. To further
aid in the installation of the tile courses, each of the
tiles is provided with a vertical guide line 18 centrally
located in the upper portion of the tile and extending
vertically downwardly. There may be circumstances when it
is desired to clip the top corners of the tile and score
lines 20 may be provided to allow this to be accomplished
in an easier manner.
To allow the plastic tile 10 of the present invention
to be utilized in hip and ridge locations where two roof
surfaces meet at an angle, a special hip and ridge tile may
be provided with a bend line provided extending vertically
through the centre of the tile. This would allow the tile
to be easily bent inwardly or outwardly along the bend line
to accommodate hip and ridge applications.
A typical installation of the shaped plastic tile 10
of the present invention on a roof surface is illustrated
in Figure 2. To provide a suitable starter course 22, the
bottom portion of a series of tiles 10 are cut off and the
top portions rotated 180 and attached to the roof surface
leaving a suitable spacing, generally on the order of a
quarter to one eighth of an inch, between each of the
starter tiles. The first tile course is laid over the
starter course with each tile 10 of the first tile course
centrally located to overlie the gap between the starter
course tiles. The tiles 10 are attached to the roof in a
suitable manner leaving a one eighth to one quarter inch
space between the upper edges of the tiles. The succeeding
courses are then laid on top of the previous tile course in
a similar manner. Due to the presence of the centering
line 18 and the graduated exposure line or guide marks 14,
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the installation of the succeeding courses of the tiles 10
is simple and no guidelines or guide boards need be
provided on the roof. The tile 10 for the second tile
course is centered between the two centering lines of the
tiles 10 of the first course with the reveal lines of the
second tile for the required reveal lining up with the top
edges of the tiles of the first tile course. The tiles 10
are then nailed to the roof and the rest of the roof is
laid in a similar manner.
The plastic roof tiles of the present invention are
constructed of the combination of a thermoplastic,
preferably a polyolefin based polymer, and a chlorine
containing polymer in an amount to provide a final chlorine
content to the tile of between about 1 percent and about 65
percent by weight. The provision of the chlorine content in
the tile provides the tile with suitable fire retardant
property. Preferably, the polyolefin polymer is one or
more polymers selected from a polyethylene and a
polypropylene, most preferably a combination of a
polyethylene and a polypropylene. The polypropylene may be
a homopolymer or a copolymer with another suitable
thermoplastic elastomer such as EPDM, ethylene propylene
terpolymer. The polyethylene may be high density
polyethylene (HDPE) low density polyethylene (LDPE) or
linear low density polyethylene (LLDPE). While the
polyolefin polymer may be virgin material, it is preferred
that the polyolefin be derived from recycled material. By
utilizing recycled material, the cost for the tile is
greatly reduced.
The chlorine containing polymer is preferably one or
more polymers selected from the group consisting of
polyvinyl chloride (PVC), chlorinated polyvinyl chloride
(CPVC), polyvinylidene dichloride (PVDC), chlorinated
polyolefin, acrylate modified PVC, neoprene or
polychloroprene rubber, copolymers of vinyl chloride with
ethylene, propylene, vinyl acetate, vinyl dichloride, and
butadiene, copolymers of vinylidene chloride with butyl
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acrylate and nitrile, and polymer blends of PVC with
acrylonitrile-butadiene-styrene (ABS), acrylic-styrene-
acrylonitrile (ASA), nitrile rubber, and polyvinyl acetate
(EVA). Once again, while the chlorine containing polymer
may also be virgin material, it is preferred for reasons of
economy that the chlorine containing polymer also be
derived from recycled material. Particularly preferred
chlorine containing polymers are polyvinyl chloride or
neoprene rubber, most preferably neoprene rubber. The
neoprene rubber may be virgin or recycled material, virgin
material generally being not cross-linked while recycled
material is generally cross-linked. Cross-linked recycled
neoprene rubber is most preferred as the chlorine
containing polymer.
The polyolefin based polymer is generally present in
an amount of 50 to 95 percent by weight and the chlorine
containing polymer is generally present in the amount of 5
to 50 percent by weight. Preferably, the polyolefin
polymer is present in an amount of 60 to 75 percent by
weight and the chlorine containing polymer is present in an
amount of 25 to 40 percent by weight. Most preferably the
polyolefin based polymer is present in an amount of 65 to
70 percent by weight and the chlorine containing polymer in
an amount of 30 to 35 percent by weight.
When the polyolefin based polymer is a combination of
polyethylene and polypropylene it is preferred if the
formulation contains 5 to 75 percent polyethylene with the
balance being polypropylene. More preferably the
formulation contains 20 to 50 percent by weight of
polyethylene and 50 to 80 percent by weight of
polypropylene. In order to improve the impact resistance
of the tile formulated from the material, it is preferred
if the polypropylene is a rubber or EPDM modified
polypropylene.
The shaped plastic roof tiles of the present invention
may be colored to any desired color by the addition of
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pigments commonly employed in the manufacture of molded
thermoplastic materials. Depending upon the nature of the
recycled material used for the shaped plastic tile,
additional pigments may or may not be required.
The plastic roof tiles are manufactured by mixing the
polyolefin or other thermoplastic based polymer and the
chlorine containing polymer to provide for a relatively
uniform mixture and then molding the mixture into the roof
tile shape. When utilizing virgin material in the form of
powder, pellets or flakes, the polyolefin based polymer
powders and chlorine containing polymer powder are mixed
and then molded utilizing either compression molding or
injection molding.
When utilizing recycled material it may be necessary
to regrind the material prior to the molding depending upon
the physical nature of the recycled material. If the
recycled material is provided in a small enough particle
size it may be handled in a manner similar to virgin
material by merely mixing, then melting and molding the
material utilizing compression molding or injection
molding. If the recycled material has not been reduced in
particle size or bulk it is generally necessary to first
reduce the bulk in particle size by grinding or densifying
the material into suitable size particles for the molding
operation.
As noted above the shaped plastic tile of the present
invention is most preferably constructed of 65 to 70
percent by weight of a polyolefin based polymer containing
20 to 50 percent by weight polyethylene and 50 to 80
percent polypropylene in combination with 30 to 35 percent
neoprene rubber as a chlorine containing polymer. The use
of the neoprene rubber as a chlorine containing polymer
provides other advantages such as providing a suitable gray
scale to the colour of the tile. In addition, the carbon
black present in the rubber also provides UV protection for
the tile. The polyolefin based polymer and neoprene rubber
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are preferably recycled material which are mixed together
in the proper proportion and densified to reduce the bulk
and particle size. The densification operation may be
accomplished by any method known in the art such as the use
of a screw extruder or utilizing suitable knives in a
chopping apparatus. During the densification operation
utilizing suitable knives, the heat generated by the
friction between the knives and the polymers melts the
plastic and causes the plastic to stick to the rubber
particles. Once the bulk and particle size has been
reduced, the mixture may be cooled with water then ground
into smaller particle sizes. These smaller particle sizes
are remelted, and molded using compression molding or
injection molding. For compression molding, the particles
are melted and placed into a compression mold having the
suitable shape and features for the roof tile and then
pressed to form the final roof tile. The roof tile may
also be formed by an injection molding operation utilizing
a suitable injection mold.
The use of the chlorine containing polymer results in
a chlorine content in the formulation in the range of 1 to
65 percent by weight. The presence of the chlorine
provides for increased resistance of the tiles in a fire
situation. Should the tiles be exposed to an open flame,
hydrogen chloride would be released during the burning of
the chloride polymer. Further flame development would be
interrupted by the hydrogen chloride reaction with hydrogen
atoms and hydroxyl radicals thus providing a suitable fire
rating to the roofing material. In addition, the presence
of the chlorine also reduces dripping of the thermoplastic
elastomer especially polyolefins during burning.
The shaped roofing tiles of the present invention
provide for an economical manufactured roof tile that
replicates the classic look of more expensive materials
such as slate without the added weight or cost of
traditional materials. A roofing system utilizing the
roofing tiles of the present invention is as easy to
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install as conventional asphalt shingles and requires no
added substructure as would be the case for slate tiles as
well as some other imitation tile.
Although various preferred embodiments of the present
invention have been described herein in detail, it will be
appreciated by those of skill in the art that variations
may be made thereto without departing from the spirit of
the invention or the scope of the appended claims.
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