U.S. patent application number 12/539822 was filed with the patent office on 2010-02-18 for roofing product with zoned functional compositions and methods of making the same.
This patent application is currently assigned to CERTAINTEED CORPORATION. Invention is credited to Gregory F. Jacobs, Husnu M. Kalkanoglu.
Application Number | 20100037548 12/539822 |
Document ID | / |
Family ID | 41680298 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100037548 |
Kind Code |
A1 |
Kalkanoglu; Husnu M. ; et
al. |
February 18, 2010 |
Roofing Product With Zoned Functional Compositions And Methods Of
Making The Same
Abstract
A roofing product having at least two separate zones, with one
of the zones having one or more certain functional characteristics
such as flame retardancy, solar reflectivity, weather resistance,
selected coloring, heat stabilization, algae resistance, and/or
solar collection for electrical generation, and another of the
zones not having such functional feature(s). The different zones
can be present in core or capstock material. The product can be
made by any of various processes, such as co-extrusion, forming,
molding, coinjection, shot injection moldings, multiple step
injection moldings and/lamination.
Inventors: |
Kalkanoglu; Husnu M.;
(Swarthmore, PA) ; Jacobs; Gregory F.; (Oreland,
PA) |
Correspondence
Address: |
PAUL AND PAUL
2000 MARKET STREET, SUITE 2900
PHILADELPHIA
PA
19103
US
|
Assignee: |
CERTAINTEED CORPORATION
Valley Forge
PA
|
Family ID: |
41680298 |
Appl. No.: |
12/539822 |
Filed: |
August 12, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61089594 |
Aug 18, 2008 |
|
|
|
Current U.S.
Class: |
52/309.1 ;
264/241 |
Current CPC
Class: |
B29C 48/307 20190201;
B29C 48/395 20190201; B32B 2419/06 20130101; Y02A 30/254 20180101;
B29L 2031/108 20130101; B32B 27/065 20130101; B32B 27/08 20130101;
B32B 3/30 20130101; B29C 48/07 20190201; B32B 2307/712 20130101;
E04D 1/20 20130101; B29C 48/21 20190201; Y10T 428/23 20150115; B32B
3/04 20130101; B32B 5/18 20130101; B32B 3/18 20130101; B29C 48/175
20190201; B32B 2307/308 20130101; B32B 27/20 20130101; B32B
2307/3065 20130101; B32B 2307/404 20130101; B32B 2307/416 20130101;
B29C 48/49 20190201; Y02B 80/00 20130101; B29C 48/12 20190201; B32B
2307/7145 20130101 |
Class at
Publication: |
52/309.1 ;
264/241 |
International
Class: |
E04C 2/20 20060101
E04C002/20; B29C 69/00 20060101 B29C069/00 |
Claims
1. A synthetic polymer based roofing product having at least a
first selectively located zone of the product that has one or more
of the following features and at least a second zone of the product
that is free of the same feature(s): (a) a flame retardant or
resistant composition; (b) a solar reflective component; (c)
multiple layers of different polymer based materials; (d) a core of
a first polymer-based material and a capstock or partial or
complete covering of another polymer-based material; (e) a
weather-resistant composition in whole or in part; (f) multiple
colors; (g) heat stabilizer composition; (h) reduced-cost filler
material; (i) algae-resistant composition; and (j) solar collection
component for electrical generation.
2. The product of claim 1, wherein said feature is a flame
retardant or resistant composition.
3. The product of claim 1, wherein said feature is a solar
reflective component.
4. The product of claim 1, wherein said first zone comprises a
capstock material.
5. The product of claim 1, wherein said second zone comprises a
core material.
6. The product of claim 4, wherein said second zone comprises a
core material.
7. The product of claim 1, wherein there is sharply delineated
interface between said first and second zones.
8. The product of claim 1, wherein there is an interface between
said first and second zones, with some intermixed material of the
first and second zones.
9. The product of claim 2, wherein said first zone comprises a
capstock material, and wherein said second zone comprises a core
material.
10. The product of claim 3, wherein said first zone comprises a
capstock material, and wherein said second zone comprises a core
material.
11. The product of claim 2, wherein said first zone comprises a
core material and said second zone comprises a capstock
material.
12. The product of claim 3, wherein said first zone comprises a
core material and said second zone comprises a capstock
material.
13. The product of claim 1, wherein at least one zone of material
includes a strength-enhancing filler material.
14. The product of claim 13, wherein said strength-enhancing filler
material includes fibrous material.
15. A process of producing a roofing product in accordance with
claim 1, wherein the process includes any of: (a) coextrusion of
polymer based compositions; (b) forming or molding to a desired
shape; (c) compression molding of the product; (d) vacuum forming
of the product; (e) coinjection molding of the product (f) two or
more shot injection moldings of the product; (g) multiple step
injection molding of the product; and (e) coinjection molding of
the product (f) two or more shot injection moldings of the product;
(g) multiple step injection molding of the product; and (h)
lamination of one or more selectively located zones to the
product.
16. The process of claim 15, wherein the process includes
lamination of one or more selectively located zones to the
product.
17. The process of claim 15, wherein the process includes
coextrusion of polymer based compositions.
18. The process of claim 15, wherein the process includes
compression molding of the product.
19. The process of claim 15, wherein the process includes
coinjection molding of the product.
20. The process of claim 15, wherein the process includes forming
or molding to a desired shape.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon U.S. provisional application
61/089,594, filed Aug. 18, 2008, and claims priority from said
provisional application.
SUMMARY OF INVENTION
[0002] This invention provides synthetic polymer based roofing
products having location specific zoned functionalities within the
product construction to provide enhanced product functionality
while making more efficient use of costly raw materials. The
invention also provides methods for producing roofing products
having zoned functionality.
FURTHER DESCRIPTION OF INVENTION
[0003] In one embodiment, a polymeric roofing shingle has flame
retardant compositions strategically located in zones of the
shingle near the lower end of the exposed zone of the shingle on a
roof, directly located in the path of flame advancement. In another
embodiment, the roofing product of the invention has a plurality of
flame retardant zones, each of the zones having a different class
of flame retardant. In yet another embodiment, the polymeric
roofing product of the invention has a solar reflective zone
selectively located in a substantial portion of the exposed portion
of the product installed on a roof.
[0004] In one process of the invention, a roofing product having
selectively located functional zones is produced by coextrusion of
polymer based compositions to provide a preformed shingle precursor
that is subsequently formed or molded to a desired shingle shape.
In one embodiment of the process, coextrusion is followed by
compression molding. In another embodiment of the process,
coextrusion is followed by a continuous vacuum forming operation.
In a further embodiment, roofing products can be made by continuous
vacuum forming with a foam backfill as as is disclosed in U.S.
patent publication US 2008/0185748A1. Additionally, the materials
can comprise a cellular core foam as is disclosed in U.S. patent
publication US 2008/0102270A1.
[0005] In another process of the invention, a roofing product
having selectively located functional zones is produced by
coinjection molding, whereby specific compositions are directed to
desired locations within an injection mold to yield the zoned
roofing product. In another embodiment of the process, a two (or
more) shot injection molding operation places the functional
compositions in different locations within the mold to provide the
zoned roofing product on removal from the mold. A process for
production of multi-zoned components by means of successive molding
methods can include the steps of injection molding one part,
transferring this part to a second mold as an insert, and molding
the second component against the first. In another injection
molding approach to produce a part having zones of differing
compositions, the process involves first injecting one material
into a single-cavity die just until the polymer has commenced to
chill against the cold wall of the mold, then immediately injecting
a second polymer to force the first polymer to the cavity
extremity. The second polymer, in this case, for example, an
intumescent plastic composition, forms the interior of the molded
article, the first forming the skin or capstock around outside of
the roofing product.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0006] The invention will now be described with reference to the
drawings.
[0007] FIG. 1 is a top perspective view of a roofing shingle having
a capstock or skin covering a core material thereover, although the
same could be a covering of core material over only the exposure
area of the shingle.
[0008] FIG. 2 is a sectional view taken generally along the line
II-II of FIG. 1.
[0009] FIG. 3 is a fragmentary sectional view taken generally along
the line III-III of FIG. 1.
[0010] FIG. 4 is an illustration similar to that of FIG. 1, but
wherein the capstock or skin is only over the
exposed-when-installed portion of the shingle, at the lower end
thereof.
[0011] FIG. 5 is a longitudinal sectional view of the shingle of
FIG. 4 of two layers of material, taken generally along the line
XII-XII of FIG. 4.
[0012] FIG. 5A is a sectional view of an alternative form of the
shingle of FIG. 4, also taken generally along the line XII-XII of
FIG. 4, but wherein a third layer of material is provided beneath
the shingle, as will be described hereinafter.
[0013] FIG. 6A is a schematic illustration of the cross section of
a shingle that is similar to that shown in FIG. 3, but wherein the
core of the shingle is essentially of one piece construction.
[0014] FIG. 6B is a schematic illustration similar to that of FIG.
6A, but wherein the core of the shingle is comprised of two
separate components.
[0015] FIG. 6C is an illustration similar to that of FIGS. 6A and
6B, but wherein the core of the shingle is comprised of two
components of different sizes.
[0016] FIG. 6D is an illustration similar to that of FIGS. 6A, 6B
and 6C, but wherein the core of the shingle is comprised of three
separate components.
[0017] FIG. 7A is a schematic perspective view of a coextruded
extrudate from which a shingle can be cut, to represent a shingle
in accordance with FIG. 6A.
[0018] FIG. 7B is an illustration similar to that of FIG. 7A, but
from which a shingle could be cut in accordance with the shingle of
FIG. 6B.
[0019] FIG. 7C is an illustration similar to that of FIG. 7A, but
from which a shingle could be cut to depict a shingle as
illustrated in FIG. 6D.
[0020] FIG. 8A is an illustration similar to that of FIG. 7A, where
in the extrudate is cut or separated into a shingle precursor, with
the illustration of FIG. 8A showing a cut being made from the
extrudate of FIG. 7A.
[0021] FIG. 8B is an illustration similar to that of FIG. 8A, but
wherein the precursor is made from an extrudate of the type of FIG.
7B.
[0022] FIG. 8c is an illustration similar to that of FIG. 8A, but
wherein the precursor is made from an extrudate of the type of FIG.
7C.
[0023] FIG. 9 is a schematic illustration of a coextrusion
apparatus for making an extrudate in accordance with this
invention.
[0024] FIG. 10 is an illustration similar to that of FIG. 9, but
wherein the extruders are shown to extrude different compositions
to the coextrusion block to produce an extrudate having zoned
composition with skin or capstock, core and flame retardant core
portion.
[0025] FIG. 11 is a schematic illustration of a section of shingle
similar to that of FIG. 5, but wherein the core is made up of three
portions.
[0026] FIG. 12 is an enlarged schematic illustration of a portion
of the shingle of FIG. 11.
[0027] FIG. 13A is a schematic illustration of a plurality of
shingles in a sloped installation on a roof deck and an
illustration of flame at the lower end thereof.
[0028] FIG. 13B is an illustration similar to that of FIG. 13A, but
wherein the effect of the heat from the flame is deflected in
accordance with this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Referring now to the drawings in detail, reference is first
made to FIGS. 1-3, wherein a roofing shingle or tile 10 is
illustrated, in the form of synthetic roofing shingle or tile. Such
article 10 is typically illustrated as having upper and lower
surfaces 11 and 12, right and left edge surfaces 13 and 14, and top
and bottom edge surfaces 15 and 16. The article 10 may take on
various other configurations as may be desired, other than the flat
configuration shown. Typically, if it is to be made in the form of
a tile, it may be flat or it may have a rounded or arched
configuration. One or more ends such as that 16 may be of various
other configurations, such as segmented, scalloped or the like, all
as may be desired. One or more surfaces 11 may have lines, grooves
or seemingly random relief areas 19, all as may be desired, for
example to give the appearance of natural material, such as a cedar
shingle, tile, slate, etc.
[0030] In general, the configurations of the various surfaces of
the roofing shingle or tile 10 are unlimited as are the sizes of
the same, within the size ranges that are generally conventional
for shingles or tiles.
[0031] With reference to FIG. 2, it will be seen that the article
10 is comprised of a skin 18 and a core 20, with the skin 18
encapsulating the top surface 21 of the core and forming
encapsulating surfaces 13, 14 and 16 of the edges that would be
weather-exposed.
[0032] The core material 20 will generally be of greater thickness
"T1" than the skin material 18 and will preferably be comprised of
a highly filled polymer. The skin material 18 will preferably be
comprised of a polymer having high weather resistance and the
ability to be colored in various colors as may be demanded by
building designers.
[0033] By combining a skin material 18 with a core material 20,
such allows an economic advantage advantage in that a greater
amount of filler may be used to comprise the core 20, which will be
of less expense than the material that comprises the skin, without
providing undesirable surface properties for the skin, and without
limiting the aesthetics of the product, because the core 20 is
encapsulated in an aesthetically pleasing and weatherable skin 18.
Additionally, the core 20 can be comprised of a foam material where
reduced weight for the product is desired.
[0034] The shingle of FIG. 4 thus has a headlap portion 131 and a
butt or tab portion 132, with relief or other aesthetically
pleasing areas 133, as shown, and with the butt or tab portion 132
having a capstock or skin 134 thereon, in the lower half of the
shingle, terminating in upper capstock edge 135, such that, when
shingles 130 are installed on a roof, a next-overlying tab or butt
portion of a shingle will cover the upper end, or headlap portion
131 of the shingle 130. Alternatively, the capstock or skin 134
could cover a greater portion or even the entire top surface 137 of
the shingle 130 (not shown). For example, the edge of the capstock
coverage could optionally extend to be coincident with the upper
edge 139 of the shingle 130.
[0035] It will also be noted that there are nailing or other
fastener reduced-thickness portions 136, in the shingle of FIG. 4,
and that the U-shaped periphery along the right and left sides and
lower edge of the shingle 130 slope downwardly from the top surface
137 to the lower surface 138, as shown at 140.
[0036] With reference now to FIG. 5, it will be seen that the slope
of the edges 140 is at an angle "a", as shown in FIG. 5, which
angle "a" will preferably be on the order of about 45 degrees (135
degrees between surfaces 137 and 140), and that such slope may be
other than a straight line, such as having some aesthetic
irregularity built into the shingle 130, as shown at the left end
of FIG. 5, corresponding to the aesthetic detail at the left end of
FIG. 4.
[0037] It will thus be seen that the skin or capstock material 134
can substantially encapsulate the tab or butt portion of the
shingle of FIGS. 4 and 5, that is to be the exposed portion of the
shingle 130 when the shingle is installed on a roof, leaving the
core material 141 to comprise a majority of the volume of the
shingle 130.
[0038] In another embodiment, the skin or capstock material can
substantially encapsulate the entire top surface of the shingle
130, the core material comprising a majority of the volume of the
shingle 130. In this embodiment portions of an underlying shingle
between a pair of adjacent shingles in an overlying course are
protected with the more durable skin or capstock material.
[0039] It will be understood that the core is preferably
constructed of an inexpensive material, and that the capstock is
preferably constructed of a material, such as but not limited to, a
polymer having a high weather resistance and the ability to be
colored in various colors, as well as desirable ultraviolet
characteristics. In this case where a capstock also covers the
upper portion or headlap area of the top surface of the shingle
130, the capstock on the upper portion may be of the same or
different color or appearance as that covering the lower portion
134.
[0040] It will also be understood that the shingle 130 may be
constructed in various other configurations, to have edges that are
segmented, scalloped or the like, or as may be desired. The relief
areas 133 may comprise lines, grooves, or seemingly random relief,
as may be desired, all to give the appearance of natural material
such as slate, tile, cedar shake or the like. It will also be
apparent that the shingles or tiles 130 may be constructed of
various sizes as may be desired.
[0041] With reference to FIG. 5A, it will be seen that a shingle
150 is provided, also having a core material 151 and a capstock
material 152, like that of the shingle 130 of FIG. 5, but wherein a
third layer 153 of another material is provided, that essentially
sandwiches the core material 151 between the capstock material 152
and the third layer 153 of material, in the tab or butt portion 154
of the shingle. The shingle of FIG. 5A can be constructed using
coextrusion followed by compression molding; however, the
coextrusion in the case of the embodiment of FIG. 5A would be in
the form of three material layers rather than two layers, with the
bottom layer 153 being comprised either of the same material as
that of the capstock layer 152, or of a different, third layer. In
the case of the instant invention, the additional layer of material
provides a specific function such as, for example, imparting flame
retardant properties or providing a portion of a solar reflective
structure. In an alternative configuration to be discussed later,
the functional materials in the core portion of the shingle are
distributed laterally along the length of the shingle and not in
layers vertically through the shingle body.
[0042] The core material will generally be of greater thickness
than the skin material and will preferably be comprised of a highly
filled polymer. In this invention portions of the core will have
different compositions to provide, for example, flame retardance in
localized regions of the shingle. The skin material will preferably
be comprised of a polymer having high weather resistance and the
ability to be colored in various colors as may be demanded by
building designers.
[0043] The relative thickness of the capstock material to that of
the core material can be about 10%, although, if additional
capstock thickness is desired, one can increase this relative
thickness up to about 20%. The minimum thickness of the capstock
material should be on the order of about 4 mils, and the range for
the same could be from about 4 mils up to about 20 mils. In some
instances, a 5% ratio of capstock material to the total thickness
of the shingle can suffice, such that the capstock material would
comprise 5% of the total thickness, with the core material
comprising 95% of the total thickness of the shingle.
[0044] It will also be understood that variations can be made in
the mold design, by varying angles, radiuses and the like to avoid
excessive thinning of the capstock material, all with a view toward
controlling the capstock coverage of the core material, not only on
the major surfaces, but also at the edges. In some cases, portions
of the core zone are structured and have hollowed out sections to
the shingle profile. Mold design can also be used to provide
recesses or indentations in the lower surface of the shingle, thus
allowing lesser amounts of material to be used.
[0045] By combining a skin material with a core material, such
allows an economic advantage in that a greater amount of filler may
be used to comprise the core, which will be of less expense than
the material that comprises the skin, without providing undesirable
surface properties for the skin, and without limiting the
aesthetics of the product, because the core is, at least partially,
encapsulated in an aesthetically pleasing and weatherable skin.
Additionally, the core can be comprised of a foam or microcellular
foam material where reduced weight for the product is desired. By
providing lateral distribution of differing compositions in
selected portions of the core material, an economic advantage can
be gained in the local deployment of specialty additives such as
flame retardants, for example, in zones of the shingle where the
flame retardant effect is most beneficial.
[0046] Further, it is known that many additives for effecting flame
retardant properties can impart reduced weatherability to polymer
compositions including such additives when parts made from such
compositions are exposed to the elements. Inclusion of the flame
retardant chemistries beneath a more highly weatherable skin or
capstock provides outdoor durability and desirable appearance to a
roofing product while taking advantage of improved material usage
efficiency. Selective placement of flame retardant additives,
including intumescents, in the lower portion of the exposure zone
of the roofing product provides improved resistance to flame
progress.
[0047] In this invention, the core material is made up of a
plurality of zones having specific functionality imparted to
various locations within the shingle, such as, for example, flame
retardant zones, foamed zones for weight reduction, constructions
having solar reflectance, and the like.
[0048] FIG. 6A is similar to the section shown in FIG. 3, but with
the section of shingle 10 having a core 20 and capstock or skin
layer 18, the section extending all the way from the bottom edge 16
to the top edge 15.
[0049] FIG. 6B shows a section of shingle 30 having a top edge 35
and a bottom edge 36, and a capstock or skin layer 38 covering a
core with portions 40 and 42, core portion 42 making up the body
underlying the exposure portion of the shingle, portion 42 further
comprised of a flame retardant or flame resistant composition.
[0050] FIG. 6C shows a section of shingle 50 having a top edge 55
and a bottom edge 56, and a capstock or skin layer 58 covering a
core with portions 60 and 62, core portion 62 making up the body
underlying the lower end of the exposure portion of the shingle,
portion 62 further comprised of a flame retardant or flame
resistant composition.
[0051] FIG. 6D shows a section of shingle 70 having a top edge 75
and a bottom edge 76, and a capstock or skin layer 78 covering a
core with portions 80, 82 and 84, core portion 82 making up the
body underlying the lower end of the exposure portion of the
shingle, and core portion 84 making up the body underlying the rest
of the exposure portion of the shingle. In this embodiment, two
different functional compositions are used for the material of core
portions 82 and 84. In one such embodiment, the core portion 82
includes an intumescent composition capable of expanding to a
greater volume on exposure to an intense heat source such as a
flame. In another such embodiment, core portion 84 includes a
second fire retardant composition. The second fire retardant
composition may be another intumescent material, or it may provide
fire retardant characteristics through a different mechanism of
fire retardant activity such as endothermic degradation, dilution
of fuel, dilution of gas phase reactants, or gas phase radical
quenching.
[0052] In any of the embodiments of FIGS. 6A-6D the capstock or
skin layers 18, 38, 58 and/or 78 could be comprised of different
capstock portions, zones or sections of different functional
compositions having different qualities that could be the same as
or different than the qualities of the different core portions 40,
42, 60, 62, 80, 82 and 84, as may be desired.
[0053] FIGS. 7A, B, and C, show perspective views of coextruded
extrudates that could be used to generate shingles such as those
depicted in section in FIGS. 6A, 6B and 6D, respectively. FIG. 7A,
for example shows extrudate 25 coming out of an extruder (not
shown) in direction 27. Extrudate 25 has a capstock or skin layer
18 and a core 20. Extrudate 45 of FIG. 7B has a capstock having two
laterally disposed segments of differing core materials 40 and 42,
core portion 42 including a flame retardant composition, with the
multicomponent core covered by capstock or skin layer 38. Extrudate
85 of FIG. 7C has a capstock having three laterally disposed
segments of differing core materials 80, 82 and 84, core portion 82
including an intumescent flame retardant composition and core
portion 84 including a second flame retardant composition, with the
multicomponent core covered by capstock or skin layer 78.
Optionally, the second flame-retardant composition of core portion
84 differs from that of core portion 82.
[0054] FIGS. 8A, B and C also include three illustrations showing
the extrudates 25, 45 and 85 cut or separated into shingle
precursors 28, 48, and 88, respectively. The shingle precursors are
suitable for continuing through a shingle making process to a
compression molding step for the formation of shingles 10, 30 and
70, respectively. Such processes are described in, for example, US
Patent application 2006/0029775A1, PCT Patent application
PCT/US07/85900, filed Nov. 29, 2007, and U.S. provisional patent
application 60/955,051, filed Aug. 10, 2007.
[0055] FIG. 9 depicts a coextrusion apparatus 200 producing an
extrudate 225 in direction 227. The apparatus 200 includes three
extruders 205, 210 and 215, each having a screw 206, 211, 216 with
flights 207, 212, 217 for transport of material within the
extruder. Each extruder has an exit 208, 213, 218 through which
material is fed to a coextrusion block 220 to a coextrusion die
221. The three extruders may each be extruding the same material,
or, alternatively, one or more of the extruders may feed different
compositions to the coextrusion block and die.
[0056] FIG. 10 depicts a coextrusion apparatus 300 producing an
extrudate 345 in direction 327. The apparatus 300 includes three
extruders 305, 310 and 315, each having a screw 306, 311, 316 with
flights 307, 312, 317 for transport of material within the
extruder. Each extruder has an exit 308, 313, 318 through which
material is fed to a coextrusion block 320 and to a coextrusion die
321. In this case, the three extruders are extruding the differing
compositions to the coextrusion block and die to produce an
extrudate having zoned composition with skin or capstock 338, core
portion 340 and flame retardant core portion 342 (edge section
shown in profile at right of FIG. 10). The dashed line 347 shows in
phantom through the capstock 338 the location of the boundary
between the core portions 340 and 342. Optionally, four or more
extruders (not shown) could be included as a part of the apparatus
feeding the coextrusion block and die with yet another composition
to produce an extrudate having another functional zone such as, for
example, extrudate 85 of FIG. 8.
[0057] It will be understood that roofing products of the invention
can be individual shingles such as synthetic slates or shake.
Further, roofing products of the invention can be panelized in
structure where intumescent features are strategically located in
the roofing panel.
[0058] In a process to produce a panelized roofing product, a sheet
of co-extruded hot polymeric material having a core portion
including an intumescent composition located adjacent to what will
eventually become the bottom edge of a roofing panel is provided
and disposed onto a rotating belt. The rotating belt includes a
mold impression therein and a plurality of apertures therethrough.
The mold impression resembles a plurality of adjacent shingle
impressions of substantially the same length. Each of the shingle
impressions includes a bottom edge where the shingle impressions
give the appearance of individual shingles. Vacuum pressure is
applied to the hot polymeric material through the belt, so as to
draw the sheet into intimate forming contact with the mold
impression to form a patterned central portion. The patterned
central portion is cooled below the heat deflection temperature of
the polymeric material. A length of the sheet is severed to produce
a shaped polymeric article. In one embodiment, each of the shingle
impressions includes a bottom edge where at least one of the bottom
edges is beveled to give the appearance of shingles having
different lengths. Such useful processes are discussed in further
detail in U.S. Pat. No. 6,737,008.
[0059] FIG. 11 shows a section of another shingle or roofing
product according to the invention. Shingle 90 has a top edge 95
and a bottom edge 96. Skin or capstock 98 covers the outer portion
of the shingle and has at least partial infrared transparency. The
core is made up of three portions. Core portion 100 is filled for
mechanical properties and bulk with cost efficient filler systems.
Core portion 102 provides flame retardance, optionally
intumescence, at the lower edge of the shingle. Core portion 106
provides reflectance of infrared radiation. Core portion 106 is
disposed disposed beneath the outer capstock layer 98 in at least
the exposure portion of the shingle.
[0060] FIG. 12 shows a close-up 110 of the bottom edge 96 of
shingle 90. Infrared light (IR) impinging on the shingle passes
through the capstock 98 to be reflected by infrared reflective
layer 106. Thus, a solar reflective flame retardant roofing product
is provided.
[0061] FIGS. 13A and 13B show shingles in place on a sloped
installation. In fire situations and flammability testing of roofs,
a flame is directed up the slope of a roof deck. As the roof deck
501 becomes hot enough flames can traverse up the roof. FIG. 13A
shows an array 500 of shingles 515 on a roof deck 501. A flame 510
is depicted at the lower edge of the array and a heat and flame
path is shown by direction arrows 520. Shingles 515 are not
provided with an intumescent zone at their lower edge. FIG. 13B
shows another array 550 of shingles 565 on a roof deck 551. In this
case, the shingles 565 have an intumescent zone 575 in the core
portion closest to the bottom edge of the shingles. A flame source
560 is applied to the array of shingles 550 and the lowermost
shingle in the array 550 has intumesced and expanded in dimension
at its lower end 580 in the path of the flame. The heat and flame
path 570 has been deflected up and away from the plane of the array
of shingles 550 by the intumesced zone 580 of the lowermost
shingle. Such change in the flame path has the potential to delay
the flame progress up the roof and lengthen the time of survival of
the roof. The increase in duration of protection of the roof from
flames provides a measure of safety for inhabitants to exit a
structure having such a roof and a bit more time for fire fighters
addressing an emergency situation.
[0062] In providing functionalized zones in the core of the
shingle, one particularly desirable functionality is flame
retardancy. Flame retardants can be included in the composition of
selected portions of the core. Flame retardants are materials that
inhibit or resist the spread of fire. These can be separated into
several categories: [0063] Minerals such as asbestos, compounds
such as aluminium hydroxide, magnesium hydroxide, antimony
trioxide, various hydrates, red phosphorus, and boron compounds,
mostly borates. [0064] Tetrakis (hydroxymethyl) phosphonium salts,
made by passing phosphine gas through a solution of formaldehyde
and a mineral acid such as hydrochloric acid, are used as flame
retardants for textiles. [0065] Synthetic materials such as
halocarbons. These include organochlorines such as polychlorinated
biphenyls (PCBs), chlorendic acid derivates (most often dibutyl
chlorendate and dimethyl chlorendate) and chlorinated paraffins;
organobromines such as polybrominated diphenyl ether (PBDEs), which
be further broken down into pentabromodiphenyl ether (pentaBDE),
octabromodiphenyl ether (octaBDE), decabromodiphenyl ether
(decaBDE) and hexabromocyclododecane (HBCD). Synthetic flame
retardant materials also include organophosphates in the form of
halogenated phosphorus compounds such as tri-o-cresyl phosphate,
tris(2,3-dibromopropyl) phosphate (TRIS), bis(2,3-dibromopropyl)
phosphate, tris(1-aziridinyl)-phosphine oxide (TEPA), and
others.
[0066] Flame retardants can have various mechanisms of function to
retard progress of flames and burning of compositions including
them. For example, some compounds break down endothermically when
subjected to high temperatures. Magnesium and aluminium hydroxides
are an example, together with various hydrates, such as alumina
trihydrate. The reaction removes heat from the surrounding, thus
cooling the material. Care is needed with such flame retardants
during polymer processing so as to remain below the decomposition
temperature while a product is being manufactured. An alternative
mechanism for flame retardance is the dilution of fuel. Inert
fillers such as talc or calcium carbonate, act as diluents,
lowering the amount of the combustible portion of the material,
thus lowering the amount of heat per volume of material that can be
produced while burning. Other flame retardants can act through a
thermal shielding mechanism. A way to stop spreading of the flame
over the material is to create a thermal insulation barrier between
the burning and unburned parts. Intumescent additives can be
employed to turn the polymer into a carbonized foam, which
separates the flame from the material and slows the heat transfer
to the unburned fuel. Yet another mechanism for flame retardant
action is the dilution of gas phase reactants in the flame. Inert
gases such as carbon dioxide and water produced by thermal
degradation of some materials act as diluents of the combustible
gases, lowering their partial pressures and the partial pressure of
oxygen, and slowing the reaction rate to inhibit burning. Still
another mechanism for flame retardance is gas phase radical
quenching. Chlorinated and brominated materials undergo thermal
degradation and release hydrogen chloride and hydrogen bromide.
These react with the highly reactive H. and OH. radicals in the
flame, resulting in an OH. radicals in the flame, resulting in an
inactive molecule and a Cl. or Br. radical. The halogen radical has
much lower energy than H. or OH., and therefore has much lower
potential to propagate the radical oxidation reactions of
combustion. Antimony compounds tend to act in synergy with
halogenated flame retardants.
[0067] Thermoplastic polyolefins, including polypropylene can be
used in combination with a flame retarder. Examples of suitable
flame retarders for use with polyolefins are inorganic compounds
such as antimony flame retarders, aluminum hydroxide, magnesium
hydroxide, zinc borate, guanidine flame retarders and zirconium
flame retarders; phosphates and phosphorus compounds such as
ammonium polyphosphate, ethylenebistris(2-cyanoethyl)phosphonium
chloride, tris(tribromophenyl)phosphate, and
tris(3-hydroxypropyl)phosphinoxide; chlorine-containing flame
retarders such as chlorinated paraffin, chlorinated polyolefin and
perchlorocyclopentadecane; and bromine containing flame retarders
such as hexabromobenzene,
n-ethylene-bisdibromonorbornane-dicarboxyimide,
ethylene-bistetrabromophthalimide, tetrabromobisphenol-A
derivatives, tetrabromobisphenol S and tetrabromodipentaerythritol.
These flame retarders may be used with polyolefin polymers each
alone or in a mixture of two or more.
[0068] In addition, intumescent additives can be used with
polyolefin polymers to make an intumescent plastic roofing product,
preferably a roofing product with selected zones having intumescent
qualities. In some embodiments, the intumescent plastic also
comprises a heat stabilizer that is compatible with the polymer.
Preferably, the heat stabilizers include, for example, thioesters
such as distearylthiodipropionate (DSTDP) and a butylated reaction
product of p-cresol and dicyclopentadiene (WINGSTAY L), which is a
very effective hindered phenol antioxidant, and combinations
comprising at least one of the foregoing heat stabilizers. It is
noted that distearylthiodipropionate is commercially available as
DSDTP from Witco Corporation, Greenwich, Conn., and the phenol is
available as WINGSTAY L from R. T. Vanderbilt, Norwalk, Conn. In
addition to these heat stabilizers, magnesium oxide may be employed
to absorb evolved HCl produced during aging of any chlorinated
components that may be included in the polymer mixture and thus act
as an effective dehydrochlorination stabilizer. Other heat
stabilizers include hydroquinone derivatives, organic phosphite
heat stabilizers such as tetraphenyl dipropylene glycol
diphosphate, and amine antioxidants, and combinations comprising at
least one of the foregoing heat stabilizers.
[0069] The intumescence additives of the intumescent plastic
include gas-generating foaming agents and char-forming agents and
combinations comprising at least one of the foregoing additives.
Gas-generating foaming agents are used in the compositions to
generate gases in order to foam the resin matrix before it is
consumed by fire. Two desirable gas-generating agents are ammonium
dihydrogen phosphate, NH.sub.4H.sub.2PO.sub.4, ammonium
polyphosphate (NH.sub.4PO.sub.3).sub.n, and combinations comprising
at least one of the foregoing agents, which emit ammonia when
heated. Hydrated alumina, hydrated magnesia, and combinations
comprising at least one of the foregoing agents are also desirable,
because they emit water vapor when heated. It is noted that the
ammonium dihydrogen phosphate can also form phosphoric acid, which
may act as a catalyst to encourage char formation from polyhydroxy
compounds. Preferably, the intumescent plastic comprises at least
one of ammonium dihydrogen phosphate and ammonium polyphosphate,
and at least one of hydrated alumina, hydrated magnesia and
melamine, or combinations comprising at least one of the foregoing
gas-generating foaming agents.
[0070] Char-forming agents for the intumescent plastic include
starch (e.g., corn starch) or other carbohydrates that form heavy
char when exposed to fire. Polyhydric alcohols such as trihydroxy
alcohols and tetrahydroxy alcohols, and combinations comprising at
least one of the foregoing alcohols, may also perform the same
function. Preferably, char forming agents are selected from the
group consisting of monopentaerythritol, dipentaerythritol, and
combinations thereof comprising at least one of the foregoing
char-formers. For example, a desirable char formation agent is a
blend of monopentaerythritol and dipentaerythritol, which is
commercially available as PERSTORP PE from Perstorp Compounds,
Inc., Florence, Mass.
[0071] Other optional ingredients may be added to the intumescent
plastic. A filler such as, for example, glass fibers, mica
particles, titanium oxide powder, and combinations comprising at
least one of the foregoing fillers, may be added to help strengthen
the composition and develop a strong structure of the material
after intumescing. Glass fiber reinforcing filler lead to increased
strength in the structure of the intumescent material after
burning. Other fillers that can also provide strength to the
residue are titanium dioxide, graphite, mica, and combinations
comprising at least one of the foregoing fillers. Antimony oxide
and/or zinc borate may also be added to impart fire impart fire
retardancy to the intumescent plastic and slow down the burning
process. This effect is helpful in decreasing heat release rate
during fire and increasing the char content.
[0072] In roofing applications, it is important that the material
be able to withstand impact and have higher flexural modulus.
Commercially available thermoplastic polyolefin resins, such as
polyethylene or polypropylene, can be used including linear low
density polyethylene. Polypropylene is the preferred polyolefin,
having highly crystalline isotactic and syndiotactic forms.
Crystalline block copolymers of ethylene and propylene, which are
plastics distinguished from amorphous, random ethylene-propylene
elastomers, can also be used. Included among the polyolefin resins
are the higher alpha-olefin modified polyethylenes and
polypropylenes. Other thermoplastic compositions can include a
crystalline, high molecular weight solid product formed by the
polymerization of one or more polyolefins selected from the group
consisting of ethylene, propylene, 1-butene, 1-hexene,
2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene and
5-methyl-1-hexene. In one preferred embodiment, a co-polymer has a
melt flow resin value of 12 and a homopolymer has a melt flow resin
value of 4. In another preferred embodiment, the thermoplastic
polyolefin has a fractional melt flow index; i.e., less than 1.
[0073] Phosphorous flame retardants are classified by the way they
interact with materials that are subject to ignition. Phosphorous
compounds can be separated into four classes based on the number of
phosphorous-oxygen and phosphorous-carbon bonds: phosphate,
phosphonate, phosphinate and phosphine oxide. The two that are
flame retardants are the phosphates and phosphonates. Condensed
phase includes a reaction that affects the burning characteristics
of the polymer. Nonvolatile acids are dehydration catalysts. These
catalysts are the char producers. Vapor phase is described as
forming phosphorous oxides which act as free radical scavengers and
inhibit ignition by depleting the hydrogens in the fire.
[0074] A preferred halogen-free, flame-retardant system based on
ammonium polyphosphate is Hostaflam TP AP 750 system, available
from Hoechst Chemicals. Unlike chlorinated or brominated flame
retardants, the Hostaflam TP AP 750 flame-retardant system forms a
carbonaceous foam with the thermoplastic material as a result of
intumescent action which serves as an insulative barrier, reduces
the access of oxygen and prevents the polymer from dripping. A
preferred flame-retardant system includes a very high phosphoric
acid amount with a neutral pH in an aqueous system. The system
includes at least fifteen percent phosphorous. In a preferred
embodiment, the Hostaflam TP AP 750 in the thermoplastic
composition making up the core in the lower portion of the exposure
zone of the roofing product is present in an amount of about 20 to
about 30 percent by weight.
[0075] Fillers, such as aluminum trihydrate, hydrated magnesium, or
hydrated calcium silicate, can also be included in the composition.
Other fillers which can be used include those commonly used in
plastic compounding, such as clays, talcs, carbonates, carbon
black, hydrates and oxides. In a preferred embodiment, calcium
carbonate is used.
[0076] The processability of candidate materials for intumescent
core portions of roofing products can be evaluated by subjecting
samples of the blend to such shaping operations as injection
molding or compression molding. For satisfactory injection molding,
the material must form in the mold a homogeneous article of uniform
strength. The flow viscosity characteristics of such blends are
adequate to insure filling the mold properly under the operating
conditions. In processing the inventive blend by an injection
molding process, it is advantageous to include a lubricant,
particularly from the standpoint of improving the molding quality
of the blend composition. In a preferred embodiment, the lubricant
is selected from the group consisting of Akzo Armeen 18 D and
Vanfre from Vam. For this purpose, any known lubricant
conventionally used in plastics processing can be used, generally
in amounts varying from about 0.1-3 parts by weight per 100 parts
of the resin blend. In a preferred embodiment, about 0.5-1 part by
weight per 100 parts of the resin blend can be used.
[0077] In processing the resin blend, a three component stabilizer
system may be employed to obtain a desirable product. The first
component of the stabilizer system includes a high molecular weight
multi-functional sterically hindered phenol, such as
tetrakis-(methylene 3-(3',5'-distert butyl-4'-hydroxyphenyl)
propionate methane), more simply referred to as "tetrakis methane",
available from Ciba Geigy Corporation under the trademark Irganox
1010. The high molecular weight multifunctional sterically hindered
phenol functions as an antioxidant and thermal stabilizer. The
second component of the stabilizer system is an alkali ester of a
thiodipropionic acid such as diauryl thiodipropionate which
functions as a second antioxidant. The third component of the
stabilizer system is a substituted benzotriazole, such as
2-(3',5'-di-tert-butyl-2'hydroxyphenyl)-5-chlorobenzotriazole
available under the trademark Tinuvin 327 from Ciba Geigy
Corporation and functions in the stabilizer system to protect the
polymeric blend against ultraviolet radiation. The amount of
stabilizer system can vary from about 0.5-10 parts by weight, and
preferably about 1-3 parts by weight of the thermoplastic
composition.
[0078] All patents and applications cited in this disclosure are
incorporated by reference into this disclosure in their entirety,
as are the following patents, patent applications, patent
publications or other patent documents:
[0079] U.S. Pat. No. 6,808,785
[0080] U.S. Pat. No. 7,351,462
[0081] US 2006/0029775A1
[0082] U.S. Pat. No. 6,536,177
[0083] WO 2007/0064322A1
[0084] US20080102270A1
[0085] U.S. Pat. No. 6,730,381
[0086] U.S. Pat. No. 5,538,777
[0087] U.S. Pat. No. 6,158,171
[0088] U.S. Pat. No. 6,114,036
[0089] U.S. Pat. No. 5,356,710
[0090] U.S. Pat. No. 5,521,003
[0091] U.S. Pat. No. 6,737,008
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