U.S. patent application number 14/414198 was filed with the patent office on 2015-07-16 for asphaltic sheet materials including expandable graphite.
The applicant listed for this patent is FIRESTONE BUILDING PRODUCTS CO., LLC. Invention is credited to Robert Anderson, Lance Black, Donald Kirk, Joseph Standeford, James Young, Wensheng Zhou.
Application Number | 20150197884 14/414198 |
Document ID | / |
Family ID | 53520843 |
Filed Date | 2015-07-16 |
United States Patent
Application |
20150197884 |
Kind Code |
A1 |
Zhou; Wensheng ; et
al. |
July 16, 2015 |
ASPHALTIC SHEET MATERIALS INCLUDING EXPANDABLE GRAPHITE
Abstract
An asphaltic sheet comprising an asphaltic component including
an asphalt binder and expandable graphite.
Inventors: |
Zhou; Wensheng; (Carmel,
IN) ; Kirk; Donald; (St. Charles, MO) ; Young;
James; (Carmel, IN) ; Anderson; Robert;
(Chicago, IL) ; Standeford; Joseph; (Indianapolis,
IN) ; Black; Lance; (Indianapolis, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FIRESTONE BUILDING PRODUCTS CO., LLC |
Indianapolis |
IN |
US |
|
|
Family ID: |
53520843 |
Appl. No.: |
14/414198 |
Filed: |
July 12, 2013 |
PCT Filed: |
July 12, 2013 |
PCT NO: |
PCT/US2013/050251 |
371 Date: |
January 12, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13804202 |
Mar 14, 2013 |
|
|
|
14414198 |
|
|
|
|
61670864 |
Jul 12, 2012 |
|
|
|
61684180 |
Aug 17, 2012 |
|
|
|
61694435 |
Aug 29, 2012 |
|
|
|
Current U.S.
Class: |
428/339 ;
427/186; 428/221; 428/408 |
Current CPC
Class: |
C08K 3/04 20130101; C09D
163/00 20130101; Y10T 428/249921 20150401; C08L 2555/84 20130101;
Y10T 428/31815 20150401; D06M 15/17 20130101; C08L 2666/55
20130101; Y10T 428/269 20150115; D06M 11/74 20130101; B32B 11/046
20130101; B32B 11/02 20130101; C08K 7/24 20130101; B32B 5/02
20130101; B32B 2260/042 20130101; C08L 2555/50 20130101; D06M
2200/10 20130101; B32B 2262/101 20130101; C09D 195/00 20130101;
D06M 2101/00 20130101; B32B 11/10 20130101; Y10T 428/30 20150115;
C08L 95/00 20130101; B32B 2262/0269 20130101; E04D 12/002 20130101;
Y10T 442/2213 20150401; B32B 2262/0276 20130101 |
International
Class: |
D06M 11/74 20060101
D06M011/74; D06M 15/17 20060101 D06M015/17 |
Claims
1-28. (canceled)
29. An asphaltic sheet comprising: (i) an asphaltic component
including an asphalt binder; and (ii) a layer including expandable
graphite, where said layer is adjacent to said asphaltic
component.
30. The asphaltic sheet of claim 29, where the asphaltic component
further includes a polymeric modifier dispersed within the asphalt
binder.
31. The asphaltic sheet of claim 29, where the asphaltic component
includes a textile fabric embedded therein.
32. The asphaltic sheet of claim 29, further including a polymeric
layer laminated to said asphaltic component.
33. The asphaltic sheet of claim 29, where said asphaltic component
is a planar body of asphalt material and includes first and second
planar surfaces, and where said expandable graphite is deposited on
said first planar surface, and further including a polymeric layer
laminated to said first planar surface.
34. The asphaltic sheet of claim 29, further including a release
film removably secured to said second surface.
35. The asphaltic sheet of claim 29, where the expandable graphite
is characterized by an onset temperature of at least 130.degree.
C.
36. The asphaltic sheet of claim 29, where the asphaltic component
further includes a flame retardant dispersed within the asphalt
binder.
37. The asphaltic sheet of claim 29, where the thickness of the
layer including expandable graphite is from about 10 .mu.m to about
3 mm.
38. A composite sheet comprising: (i) a planar body including
asphalt material, said planar body having first and second opposed
planar surfaces; (ii) expandable graphite deposited on said first
planar surface.
39. The composite sheet of 38, further including a polymeric sheet
laminated to said first planar surface of said planar body thereby
sandwiching said expandable graphite between said planar body and
said polymeric sheet.
40. The composite sheet of claim 38, further including a textile
embedded within said planar body of asphalt.
41. The composite sheet of claim 38, further including a release
film removably secured to said second planar surface of said planar
body.
42. The composite sheet of claim 38, further including release
agents deposited on said first planar surface.
43. The composite of claim 38, where said expandable graphite is
held in place on said first planar surface by said asphalt material
of said planar body.
44. The composite of claim 38, where said expandable graphite is
adhered to said first planar surface by said asphalt material.
45. A method for producing an asphaltic sheet, the method
comprising: a. providing an asphaltic sheet; and b. applying
expandable graphite particles to the asphaltic sheet.
46. The method of claim 45, where said step of applying includes
dropping the expandable graphite onto a sheet that has been coated
with molten asphalt, and where the expandable graphite is dropped
at a rate and amount to create at least a partial layer of
expandable graphite particles adjacent to the asphalt of the coated
asphalt sheet.
47. The method of claim 45, where said step of applying includes at
least partially embedding some of the graphite particles in to the
asphalt such that the asphalt serves as a binder to hold the
graphite particles in place or serves to adhere the graphite
particles to the surface of the sheet.
48. The method of claim 45, where said step of applying includes
dropping expandable graphite on to an asphaltic sheet after the
asphaltic sheet is prepared from a molten asphalt composition and
prior to a substantial cooling of the asphalt material.
Description
[0001] This application claims the benefit of U.S. Non-Provisional
application Ser. No. 13/804,202, filed Mar. 14, 2013, and U.S.
Provisional Application Ser. Nos. 61/694,435, filed on Aug. 29,
2012, 61/684,180, filed on Aug. 17, 2012, and 61/670,864, filed on
Jul. 12, 2012, all of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention are directed toward
asphaltic sheet materials that include expandable graphite. These
sheet materials are useful as roofing underlayment, as roofing
membranes, and as barrier materials such as air, vapor, and/or
moisture barriers.
BACKGROUND OF THE INVENTION
[0003] Asphaltic sheet materials are widely used in the
construction industry. For example, polymer-modified asphaltic
sheet material is used as membrane for waterproofing flat or
low-sloped roofs. As is known in the art, these roofing systems may
include multiple layers of asphaltic sheet including base sheets
and cap sheets. Other examples include barriers materials such air,
vapor, or moisture barriers. These materials are typically used on
roofs or vertical surfaces such as walls to provide the desired
air, vapor and/or moisture resistance to a structure. Still other
examples include underlayments, which are used in the roofing
industry to provide an extra layer of protection to the roof. This
additional protection may provide, among other benefits, water,
moisture, thermal, and/or fire resistance. As the name implies,
underlayment is typically positioned below the external or primary
roofing protection, which may include shingles, membranes such as
polymeric or asphaltic membranes, roofing tiles, and metal panels
or cladding.
[0004] With regard to underlayments, felt paper that is saturated
with asphalt has historically been used as underlayment to provide
additional water and/or moisture resistance to the roof. Other
forms of underlayment include synthetic materials such as
thermoplastic or thermoset materials formed into sheets.
Composites, such as laminates of asphalt and synthetic polymer,
have also been employed as underlayment.
[0005] In order to meet certain fire resistance properties, which
may be required by code or classification, fire or flame resistant
underlayment may be employed. These underlayment may include
textiles, including woven and non-woven fabrics, made of fire
resistant materials such as fiberglass. These fabrics may include a
coating, such as a mineral coating, that further enhances the flame
or fire resistance of the underlayment.
[0006] Where there is a desire to achieve both moisture resistance
and flame or fire resistance through the use of underlayment, such
as with metal roofing systems, multiple underlayments are used. For
example, a first underlayment may be used to provide moisture or
water resistance, and a second underlayment may be used to provide
flame or fire resistance. This technique, however, suffers from
several drawbacks including the added difficulty of installing
multiple underlayments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of a cross section of an
asphaltic sheet according to one or more embodiments of the present
invention.
[0008] FIG. 2 is a cross-sectional view of an asphaltic sheet
according to one or more embodiments of the present invention.
[0009] FIG. 3 is a cross-sectional view of an asphaltic sheet
according to one or more embodiments of the present invention.
[0010] FIG. 4 is a perspective view of a building structure having
a metal or tile roofing system including an asphaltic sheet
according to embodiments of the present invention.
[0011] FIG. 5 is a perspective view of a building structure having
a flat roofing system including an asphaltic sheet according to
embodiments of the present invention.
[0012] FIG. 6 is a perspective view of a building structure having
a wall system including an asphaltic sheet according to embodiments
of the present invention.
SUMMARY OF THE INVENTION
[0013] One or more embodiments of the present invention provide an
asphaltic sheet comprising an asphaltic component including an
asphalt binder and expandable graphite.
[0014] Still other embodiments of the present invention provide a
roof system comprising a roof deck; an underlayment; and one or
more metal panels or roofing tilescovering the underlayment, where
the underlayment includes an asphaltic component including an
asphalt binder and expandable graphite dispersed within the asphalt
binder.
[0015] Still other embodiments of the present invention provide a
method for producing an asphaltic sheet, the method comprising
preparing a molten asphaltic composition by introducing an
expandable graphite to an asphalt binder at a temperature below
that which will cause deleterious expansion of the expandable
graphite, and fabricating an asphaltic sheet with the molten
asphaltic composition.
[0016] Still other embodiments of the present invention provide an
asphaltic sheet comprising an asphaltic component including an
asphalt binder and a layer including expandable graphite, where
said layer including expandable graphite is adjacent to said
asphaltic component.
[0017] Still other embodiments of the present invention provide a
method for producing an asphaltic sheet, the method comprising
providing an asphaltic sheet, and applying expandable graphite
particles to the asphaltic sheet.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0018] Embodiments of the present invention are based, at least in
part, on the discovery of an asphaltic sheet having an asphaltic
component with expandable graphite. In certain embodiments, the
asphaltic sheet includes an asphalt component with the expandable
graphite dispersed within the asphalt component. In these or other
embodiments, the asphaltic sheet includes a layer of expandable
graphite adjacent to the asphalt component. In one or more
embodiments, the asphaltic sheet is advantageously resistant to
water, moisture, an/or air due to the asphaltic nature of the
sheet, and it is also flame resistant due to the presence of the
expandable graphite. It is believed that one or more advantages of
the present invention derive from the presence of the expandable
graphite within or adjacent to the asphaltic component of the
sheet. While the prior art contemplates the use of expandable
graphite as a flame retardant, the prior art does not contemplate
incorporating the expandable graphite into the asphaltic component
of a sheet material or placing a layer of the expandable graphite
adjacent to the asphaltic component. Embodiments of the present
invention provide a method for incorporating the expandable
graphite into the asphaltic component of the sheet without
deleteriously expanding the graphite (i.e. the graphite is not
expanded to a deleterious degree). And, in certain embodiments, the
asphaltic component of the sheet material further includes a
complementary flame retardant material that is believed to
synergistically interact with the expandable graphite to provide
unexpected flame resistance.
Sheet Construction
[0019] In one or more embodiments, the asphaltic sheet is or
includes a planar body of asphalt material, which may also be
referred to as the asphalt component of the sheet or asphalt layer
12. For example, as shown in FIG. 1, asphaltic sheet 11 includes
asphalt component 12 having a first planar surface 13 and second
planer surface 14. Sheet 11 may include an optional textile fabric
15 embedded or impregnated within asphaltic component 12. In
certain embodiments, the sheet is devoid of a scrim or fabric.
Asphaltic component 12, as will be described in greater detail
below, may include various constituents such as polymeric modifiers
and fillers, as well as expandable graphite 16 and optional
complementary flame retardants (not shown) according to the present
invention. In one or more embodiments, sheet 11 may further include
one or more polymeric layers 17 laminated to asphalt component 12
of sheet 11. For example, asphaltic sheet 11 may include an
asphaltic component 12 laminated to a polypropylene sheet. In other
embodiments, layer 17 may include a layer of release agents, such
as silica, sand or talc. Additionally, a release film 19 may be
removably secured to at least one of the exposed planar surfaces 13
or 14.
[0020] In one or more embodiments, optional textile fabric 15,
which may also be referred to as fabric reinforcement 15,
reinforcing member 15, or simply reinforcement 15, may include
woven and/or non-woven fabrics. Various fabric reinforcements are
known in the art, and practice of the present invention is not
necessarily limited by the selection of a particular fabric. In one
or more embodiments, reinforcement 15 may be fabricated from
fiberglass and/or synthetic yards or filaments. Exemplary synthetic
yarns include those prepared from polyesters or polyimides.
[0021] In one or more embodiments, the thickness of asphaltic sheet
11 may be at least 10, in other embodiments at least 20, and in
other embodiments at least 30 mils. In these or other embodiments,
the thickness of asphaltic sheet 11 may be at most 120, in other
embodiments at most 100, in other embodiments at most 90, and in
other embodiments at most 80 mils. In one or more embodiments, the
thickness of asphaltic sheet 11 may be from about 10 to about 100,
in other embodiments from about 20 to about 90, and in other
embodiments from about 30 to about 80 mils. In other embodiments,
especially where the asphaltic sheet is used in a vertical
application, the thickness of the asphaltic sheet may be
substantially thinner. For example, the thickness of the sheet may
be less than 20, in other embodiments less than 15, and in other
embodiments less than 10 mils, with the thickness ranging from 2 to
20 mils, in other embodiments from 3 to 15 mils, and in other
embodiments from 5 to 10 mils.
[0022] In one or more embodiments, the weight of the asphaltic
sheet may be at least 5, in other embodiments at least 10 and in
other embodiments at least 15 pounds per hundred square feet. In
these or other embodiments, the weight of the asphaltic sheet may
be at most 90, in other embodiments at most 70, and in other
embodiments at most 50 pounds per hundred square feet. In these or
other embodiments, the weight of the asphaltic sheet may be from 5
to 100, in other embodiments from 10 to 80, and in other
embodiments from 15 to 50 pounds per hundred square feet. In other
embodiments, especially where the asphaltic sheet is used in a
vertical application, the weight of the asphaltic sheet may be
substantially lighter. For example, the weight of the sheet may be
less than 60, in other embodiments less than 50, and in other
embodiments less than 40 pounds per hundred square feet, with the
weight ranging from 5 to 60, in other embodiments from 10 to 50,
and in other embodiments from 15 to 40 pounds per hundred square
feet.
[0023] In other embodiments, as shown, for example, in FIG. 2,
asphaltic sheet 11 includes asphaltic component 12 having first
planer surface 13 and second planar surface 14. Adjacent to
asphaltic component 12 is a layer 18 including expandable graphite
16. Layer 18 may be adjacent to asphaltic component 12 as a result
of the manner in which asphaltic sheet 11 is fabricated, as will be
described in greater detail below. Asphaltic sheet 11 may carry
optional polymeric layer 17, which may also be referred to as
polymeric liner 17. In other embodiments, layer 17 may include a
layer of release agents, such as silica, sand or talc. In yet other
embodiments, layer 17 may be a glass scrim, polyester mat, metal
foil (e.g., aluminum foil), fabric, elastomeric layer, and the
like.
[0024] In one or more embodiments, layer 18 includes one or more
layers of particles of expandable graphite 16. These particles may
be held in place by a matrix of asphalt material present within at
least a portion of layer 18. In these or other embodiments, the
expandable graphite 16 is held in place by being adhered to the
surface of the asphalt. In one or more embodiments, asphaltic
component 12 may also include expandable graphite dispersed
therein. In other words, asphaltic sheet may include expandable
graphite dispersed throughout the asphaltic component and layer 18
of expandable graphite adjacent to component 12.
[0025] In one or more embodiments, layer 18 may include a planar
region within sheet 11 that includes a higher concentration of
expandable graphite relative to any other region of sheet 11. Thus,
layer 18 may include a continuous layer of expandable graphite
having a variable or relatively constant thickness across sheet 11.
Or, in other embodiments, the expandable graphite may be
discontinuous throughout the region so long as the concentration of
expandable graphite within the region is higher than in other areas
or regions of sheet 11. In one or more embodiments, the
discontinuity of the expandable graphite within the layer 18 may
result from the asphaltic material which may form a matrix in which
the expandable graphite is at least partially dispersed within this
region or layer. It should also be appreciated that the
concentration of the expandable graphite may not be constant within
this layer. Indeed, as will be appreciated from the description of
how to fabricate the sheets of this embodiment, a concentration
gradient may exist whereby the concentration of the expandable
graphite moves from a region of maximum concentration to a region
of decreased concentration. As shown in expanded view in FIG. 2,
the concentration of expandable graphite 16 furthest from planar
surface 13 within layer 18 is the highest, which corresponds to a
minimum in asphalt concentration. On the other hand, the
concentration of expandable graphite 16 proximate to planar surface
13 is a minimum relative to the concentration of expandable
graphite within layer 18.
[0026] In yet other embodiments, which may be described with
reference to FIG. 3, an additional layer of asphalt 12' is adjacent
expandable graphite layer 18 opposite asphaltic component or layer
12. Layer 12' may also be referred to as a skin layer 12', and
aspects of this embodiment may be described as layer or region 18
being embedded between layers of asphaltic binder or material.
Consistent with the other embodiments described above, this layer
12' may include expandable graphite 16 at a concentration lower
than layer 18. Nonetheless, in one or more embodiments, layer 12'
may include expandable graphite dispersed therein, although the
concentration is lower than the concentration of the expandable
graphite within region 18. In fact, in one or more embodiments, a
concentration gradient may exist between layers 12' and 18 in a
similar fashion to the concentration gradient described above.
[0027] While a continuous layer or region (e.g. region 18) is
believed to be advantageous, it is also contemplated that the sheet
can include multiple discreet regions of the expandable graphite,
such as may exist in a pattern where the expandable graphite is
applied on the top of the asphaltic sheet in rows or strips in the
machine direction of the sheet. This may be advantageous where
greater adhesion to a top sheet (e.g. sheet 17) is desired.
[0028] In one or more embodiments, the thickness of layer 18 may be
at least 10 .mu.m, in other embodiments at least 20 .mu.m, in other
embodiments at least 30 .mu.m, in other embodiments at least 75
.mu.m, and in other embodiments at least 100 .mu.m. In these or
other embodiments, the thickness of layer 18 may be at most 3 mm,
in other embodiments at most 2 mm, and in other embodiments at most
1 mm. In one or more embodiments, the thickness of layer 18 may be
from about 10 .mu.m to about 3 mm, in other embodiments from about
75 .mu.m to about 2 mm, and in other embodiments from about 100
.mu.m to about 1 mm.
[0029] In one or more embodiments, the thickness of layer 12' may
be at least 2 .mu.m, in other embodiments at least 5 .mu.m, and in
other embodiments at least 20 .mu.m. In these or other embodiments,
the thickness of layer 12' may be at most 1 mm, in other
embodiments at most 0.5 mm, in other embodiments at most 0.25 mm,
in other embodiments at most 0.1 mm, and in other embodiments at
most 0.050 mm. In one or more embodiments, the thickness of layer
12' may be from about 1 .mu.m to about 3 mm, in other embodiments
from about 2 .mu.m to about 0.5 mm, and in other embodiments from
about 5 .mu.m to about 0.050 mm.
Asphalt and Constituents
[0030] As noted above, the asphaltic sheet of one or more
embodiments of the present invention includes an asphaltic
component. The asphaltic component includes an asphalt binder and
expandable graphite dispersed within the binder. The asphaltic
component may also include, dispersed within the binder, polymeric
modifiers, fillers, tackifiers, complementary flame retardants, and
other constituents conventionally used in asphaltic-based building
materials.
Asphalt Binder
[0031] The term "asphalt binder" is used as understood by those
skilled in the art and is consistent with the meaning provided by
AASHTO M320. As used within this specification, the terms "asphalt"
and "asphalt binder" may be used synonymously. The asphalt binder
material may be derived from any asphalt source, such as natural
asphalt, rock asphalt, produced from tar sands, or petroleum
asphalt obtained in the process of refining petroleum. In other
embodiments, asphalt binders may include a blend of various
asphalts not meeting any specific grade definition. This includes
air-blown asphalt, vacuum-distilled asphalt, steam-distilled
asphalt, cutback asphalt or roofing asphalt. Alternatively,
gilsonite, natural or synthetic, used alone or mixed with petroleum
asphalt, may be selected. Synthetic asphalt mixtures suitable for
use in the present invention are described, for example, in U.S.
Pat. No. 4,437,896. In one or more embodiments, asphalt includes
petroleum derived asphalt and asphaltic residual. These
compositions may include asphaltenes, resins, cyclics, and
saturates. The percentage of these constituents in the overall
asphalt binder composition may vary based on the source of the
asphalt.
[0032] Asphaltenes include black amorphous solids containing, in
addition to carbon and hydrogen, some nitrogen, sulfur, and oxygen.
Trace elements such as nickel and vanadium may also be present.
Asphaltenes are generally considered as highly polar aromatic
materials of a number average molecular weight of about 2000 to
about 5000 g/mol, and may constitute about 5 to about 25% of the
weight of asphalt.
[0033] Resins (polar aromatics) include dark-colored, solid and
semi-solid, very adhesive fractions of relatively high molecular
weight present in the maltenes. They may include the dispersing
agents of peptizers for the asphaltenes, and the proportion of
resins to asphaltenes governs, to a degree, the sol- or gel-type
character of asphalts. Resins separated from bitumens may have a
number average molecular weight of about 0.8 to about 2 kg/mol but
there is a wide molecular distribution. This component may
constitute about 15 to about 25% of the weight of asphalts.
[0034] Cyclics (naphthene aromatics) include the compounds of
lowest molecular weight in bitumens and represent the major portion
of the dispersion medium for the peptized asphaltenes. They may
constitute about 45 to about 60% by weight of the total asphalt
binder, and may be dark viscous liquids. They may include compounds
with aromatic and naphthenic aromatic nuclei with side chain
constituents and may have molecular weights of 0.5 to about 9
kg/mol.
[0035] Saturates include predominantly the straight- and
branched-chain aliphatic hydrocarbons present in bitumens, together
with alkyl naphthenes and some alkyl aromatics. The average
molecular weight range may be approximately similar to that of the
cyclics, and the components may include the waxy and non-waxy
saturates. This fraction may from about 5 to about 20% of the
weight of asphalts.
[0036] In these or other embodiments, asphalt binders may include
bitumens that occur in nature or may be obtained in petroleum
processing. Asphalts may contain very high molecular weight
hydrocarbons called asphaltenes, which may be soluble in carbon
disulfide, pyridine, aromatic hydrocarbons, chlorinated
hydrocarbons, and THF. Asphalts or bituminous materials may be
solids, semi-solids or liquids.
[0037] In one or more embodiments, the asphalt binder includes
AC-5, AC-10 and AC-15. These asphalts typically contain about 40 to
about 52 parts by weight of aromatic hydrocarbons, about 20 to
about 44 parts by weight of a polar organic compound, about 10 to
about 15 parts by weight of asphaltene, about 6 to about 8 parts by
weight of saturates, and about 4 to about 5 parts by weight of
sulfur. Nevertheless, practice of the present invention is not
limited by selection of any particular asphalt.
[0038] In one or more embodiments, the molecular weight of the
aromatic hydrocarbons present in asphalt may range between about
300 and 2000, while the polar organic compounds, which generally
include hydroxylated, carboxylated and heterocyclic compounds, may
have a weight average molecular weight of about 500 to 50,000.
Asphaltenes, which are generally known as heavy hydrocarbons, are
typically of a high molecular weight and are heptane insoluble.
Saturates generally include paraffinic and cycloaliphatic
hydrocarbons having about 300 to 2000 molecular weight.
[0039] In one or more embodiments, bitumens may be used. Bitumens
are naturally occurring solidified hydrocarbons, typically
collected as a residue of petroleum distillation. Gilsonite is
believed to be the purest naturally formed bitumen, typically
having a molecular weight of about 3,000 with about 3 parts by
weight complexed nitrogen.
Expandable Graphite
[0040] Expandable graphite may also be referred to as expandable
flake graphite, intumescent flake graphite, or expandable flake;
and, for the purposes herein, these terms may be used
interchangeably.
[0041] In one or more embodiments, expandable graphite includes
intercalated graphite in which an intercallant material is included
between the graphite layers of graphite crystal or particle.
Examples of intercallant materials include halogens, alkali metals,
sulfates, nitrates, various organic acids, aluminum chlorides,
ferric chlorides, other metal halides, arsenic sulfides, and
thallium sulfides. In certain embodiments of the present invention,
the expandable graphite includes non-halogenated intercallant
materials. In certain embodiments, the expandable graphite includes
sulfate intercallants, also referred to as graphite bisulfate. As
is known in the art, bisulfate intercalation is achieved by
treating highly crystalline natural flake graphite with a mixture
of sulfuric acid and other oxidizing agents which act to catalyze
the sulfate intercalation.
[0042] Commercially available examples of expandable graphite
include HPMS Expandable Graphite (HP Materials Solutions, Inc.,
Woodland Hills, Calif.) and Expandable Graphite Grades 1721 (Asbury
Carbons, Asbury, N.J.). Other commercial grades contemplated as
useful in the present invention include 1722, 3393, 3577, 3626, and
1722HT (Asbury Carbons, Asbury, N.J.).
[0043] In one or more embodiments, the expandable graphite may be
characterized as having a mean or average size in the range from
about 30 .mu.m to about 1.5 mm, in other embodiments from about 50
.mu.m to about 1.0 mm, and in other embodiments from about 180 to
about 850 .mu.m. In certain embodiments, the expandable graphite
may be characterized as having a mean or average size of at least
30 .mu.m, in other embodiments at least 44 .mu.m, in other
embodiments at least 180 .mu.m, and in other embodiments at least
300 .mu.m. In one or more embodiments, expandable graphite may be
characterized as having a mean or average size of at most 1.5 mm,
in other embodiments at most 1.0 mm, in other embodiments at most
850 .mu.m, in other embodiments at most 600 .mu.m, in yet other
embodiments at most 500 .mu.m, and in still other embodiments at
most 400 .mu.m. Useful expandable graphite includes Graphite Grade
#1721 (Asbury Carbons), which has a nominal size of greater than
300 .mu.m.
[0044] In one or more embodiments, the expandable graphite may be
characterized as having a median size in the range from about 30
.mu.m to about 1.5 mm, in other embodiments from about 50 .mu.m to
about 1.0 mm, and in other embodiments from about 180 to about 850
.mu.m. In certain embodiments, the expandable graphite may be
characterized as having a median size of at least 30 .mu.m, in
other embodiments at least 44 .mu.m, in other embodiments at least
180 .mu.m, and in other embodiments at least 300 .mu.m. In one or
more embodiments, expandable graphite may be characterized as
having a median size of at most 1.5 mm, in other embodiments at
most 1.0 mm, in other embodiments at most 850 .mu.m, in other
embodiments at most 600 .mu.m, in yet other embodiments at most 500
.mu.m, and in still other embodiments at most 400 .mu.m.
[0045] In one or more embodiments of the present invention, the
expandable graphite may be characterized as having a nominal
particle size of 20.times.50 (US sieve). US sieve 20 has an opening
equivalent to 0.841 mm and US sieve 50 has an opening equivalent to
0.297 mm. Therefore, a nominal particle size of 20.times.50
indicates the graphite particles are at least 0.297 mm and at most
0.841 mm.
[0046] In one or more embodiments, the expandable graphite may be
characterized as having a carbon content in the range from about
80% to about 99%. In certain embodiments, the expandable graphite
may be characterized as having a carbon content of at least 80%, in
other embodiments at least 85%, in other embodiments at least 90%,
in yet other embodiments at least 95%, in other embodiments at
least 98%, and in still other embodiments at least 99% carbon.
[0047] In one or more embodiments, the expandable graphite may be
characterized as having a sulfur content in the range from about 0%
to about 8%, in other embodiments from about 2.6% to about 5.0%,
and in other embodiments from about 3.0% to about 3.5%. In certain
embodiments, the expandable graphite may be characterized as having
a sulfur content of at least 0%, in other embodiments at least
2.6%, in other embodiments at least 2.9%, in other embodiments at
least 3.2%, and in other embodiments 3.5%. In certain embodiments,
the expandable graphite may be characterized as having a sulfur
content of at most 8%, in other embodiments at most 5%, in other
embodiments at most 3.5%.
[0048] In one or more embodiments, the expandable graphite may be
characterized as having an expansion ratio (cc/g) in the range from
about 10:1 to about 500:1, in other embodiments at least 20:1 to
about 450:1, in other embodiments at least 30:1 to about 400:1, in
other embodiments from about 50:1 to about 350:1. In certain
embodiments, the expandable graphite may be characterized as having
an expansion ratio (cc/g) of at least 10:1, in other embodiments at
least 20:1, in other embodiments at least 30:1, in other
embodiments at least 40:1, in other embodiments at least 50:1, in
other embodiments at least 60:1, in other embodiments at least
90:1, in other embodiments at least 160:1, in other embodiments at
least 210:1, in other embodiments at least 220:1, in other
embodiments at least 230:1, in other embodiments at least 270:1, in
other embodiments at least 290:1, and in yet other embodiments at
least 300:1. In certain embodiments, the expandable graphite may be
characterized as having an expansion ratio (cc/g) of at most 350:1,
and in yet other embodiments at most 300:1.
[0049] In one or more embodiments, the expandable graphite, as it
exists with the asphaltic component of the asphaltic sheet of the
present invention, is partially expanded. In one or more
embodiments, the expandable graphite is not expanded, however, to a
deleterious degree, which includes that amount or more of expansion
that will deleteriously the ability to form the sheet product and
the ability of the graphite to serve as flame retardant at
desirable levels, which include those levels that allow proper
formation of the sheet. In one or more embodiments, the expandable
graphite is expanded to at most 60%, in other embodiments at most
50%, in other embodiments at most 40%, in other embodiments at most
30%, in other embodiments at most 20%, and in other embodiments at
most 10% beyond its original unexpanded size.
[0050] In one or more embodiments, the expandable graphite may be
characterized as having a pH in the range from about 1 to about 10;
in other embodiments from about 1 to about 6; and in yet other
embodiments from about 5 to about 10. In certain embodiments, the
expandable graphite may be characterized as having a pH in the
range from about 4 to about 7. In one or more embodiments, the
expandable graphite may be characterized as having a pH of at least
1, in other embodiments at least 4, and in other embodiments at
least 5. In certain embodiments, the expandable graphite may be
characterized as having a pH of at most 10, in other embodiments at
most 7, and in other embodiments at most 6.
[0051] In one or more embodiments, the expandable graphite may be
characterized by an onset temperature ranging from about
100.degree. C. to about 250.degree. C.; in other embodiments from
about 160.degree. C. to about 225.degree. C.; and in other
embodiments from about 180.degree. C. to about 200.degree. C. In
one or more embodiments, the expandable graphite may be
characterized by an onset temperature of at least 100.degree. C.,
in other embodiments at least 130.degree. C., in other embodiments
at least 160.degree. C., and in other embodiments at least
180.degree. C. In one or more embodiments, the expandable graphite
may be characterized by an onset temperature of at most 250.degree.
C., in other embodiments at most 225.degree. C., and in other
embodiments at most 200.degree. C. Onset temperature may also be
interchangeably referred to as expansion temperature and also
alternatively referred to as the temperature at which expansion of
the graphite starts.
Polymeric Modifiers
[0052] In one or more embodiments, the polymeric modifier, which
may simply be referred to as polymer, includes thermoplastic
polymers, thermosetting elastomers, thermoplastic elastomers,
and/or mixtures thereof. Each of these polymers have been used,
either alone or in combination with each other to modify asphalt
binders, and practice of the present invention is not necessarily
limited by the selection of any particular polymeric modifier.
[0053] In one or more embodiments, the polymers may be
characterized by a glass transition temperature (Tg), as measured
by DSC analysis, of less than 150.degree. C., in other embodiment
less than 125.degree. C., in other embodiment less than 100.degree.
C., in other embodiments less than 20.degree. C., in other
embodiments less than 0.degree. C., in other embodiments less than
-20.degree. C., in other embodiments less than -35.degree. C., and
in other embodiments from about -90.degree. C. to about -20.degree.
C. In these or other embodiments, the polymers may be characterized
by a glass transition temperature (Tg), as measured by DSC
analysis, of more than -20.degree. C., in other embodiments more
than 0.degree. C., in other embodiments more than 20.degree. C., in
other embodiments more than 50.degree. C., and in other embodiments
more than 100.degree. C.
[0054] In one or more embodiments, the polymeric modifier may be
characterized by a melt index (ASTM D-1238; 2.16 kg load @
190.degree. C.) of less than 1,000 dg/min, in other embodiments
less than 500 dg/min, in other embodiments less than 50 dg/min, in
other embodiments less than 20 dg/min, in other embodiments less
than 10 dg/min, and in other embodiments less than 1 dg/min. In
these or other embodiments, the unsaturated polymers may have a
melt index of between 3 and 15 dg/min, and other embodiments
between 4 and 12 dg/min.
[0055] In one or more embodiments, the polymeric modifier may be
characterized by a number average molecular weight (M.sub.n) of
from about 10 to about 1,000 kg/mol, in other embodiments from
about 40 to about 500 kg/mol, and in other embodiments from about
80 to about 200 kg/mol. In these or other embodiments, the
polymeric modifier may also be characterized by a weight average
molecular weight (M.sub.w) of from about 10 to about 4,000 kg/mol,
in other embodiments from about 40 to about 2,000 kg/mol, and in
other embodiments from about 80 to about 800 kg/mol. In one or more
embodiments, the polymeric modifier may be characterized by a
molecular weight distribution of from about 1.1 to about 5, in
other embodiments from about 1.5 to about 4.5, and in other
embodiments from about 1.8 to about 4.0. Molecular weight can be
determined by gel permeation chromatography (GPC) calibrated with
polystyrene standards and adjusted for the Mark-Houwink constants
for the polymer in question.
[0056] The polymeric modifier may be linear, branched, or coupled
polymers. Types of polymers may include both natural and synthetic
polymers. Useful synthetic polymers may include polydienes or
polydiene copolymers with non-diene comonomer (e.g., styrene). The
copolymers may include block and random copolymers. The coupled
polymers may include linearly coupled polymers (e.g. di-coupled
polymers) or radially coupled polymers (e.g. tri-coupled or,
tetra-coupled penta-coupled, hexa-coupled etc.). Exemplary
polydienes include polybutadiene and polyisoprene. Exemplary
copolymers may include random styrene-butadiene rubber,
styrene-butadiene block copolymer, styrene-butadiene-styrene block
copolymer, random styrene-isoprene, styrene-isoprene block
copolymer, styrene-isoprene-butadiene block copolymer, random
styrene-isoprene-butadiene, styrene-isoprene-styrene block
copolymer, and chloroprene rubber. In one or more embodiments, the
polymeric modifier include linear or radial block copolymers
wherein the block copolymers include terminal styrene blocks. In
these or other embodiments, the styrene content of these block
copolymers may be from 10% to 50% by weight, in other embodiments
from 15% to 45% by weight, and in other embodiments from 20% to 40%
by weight.
[0057] In one or more embodiments, the polymeric modifier is an SBS
block copolymer (i.e. poly(styrene-b-butadiene-b-styrene). In one
or more embodiments, these block copolymers may be characterized by
a weight average molecular weight of from about 90,000 to about
750,000, or in other embodiments from about 150,000 to about
250,000. In these or other embodiments, these polymers may be
characterized by a polydispersity of up to about 1.1 or in other
embodiments up to about 1.05. In particular embodiments, the SBS
block copolymers have from about 27 to about 43 parts by weight of
styrene.
[0058] An example of an SBS block copolymer useful for practice of
the present invention is that sold under the tradename Kraton D
(Kraton Polymer Group), including, for example, D1118, D1101, and
D1184. Included among these polymers are SBS block linear and
radial block copolymers. In particular embodiments, two block
copolymers, linear and radial, can be mixed to achieve the desired
results. In certain embodiments, the weight ratio of linear to
radial SBS copolymers may be from about 0 to about 7 parts by
weight of radial and from about 7 to about 15 parts by weight of
linear SBS block copolymer.
[0059] In one or more embodiments, useful thermoplastic polymers
that may used as the polymeric modifier include polyolefins. For
example, several derivatives of polypropylene are useful including
those prepared by first dimerizing propylene to give
4-methyl-1-pentene and subsequently polymerizing this dimer to give
poly-4-methyl-1-pentene. These polypropylenes may have a weight
average molecular weight of from about 50,000 to about 250,000, or
in other embodiments from about 150,000 to about 170,000. In one or
more embodiments, the polydispersity may be from about 2.5 to about
3.5. The polypropylene may be further characterized by a melt
temperature of from about 160.degree. C. to about 175.degree. C.,
and may have a cold crystallization temperature above 120.degree.
C.
[0060] In one or more embodiments, the polymeric modifier is
isotactic polypropylene (IPP). In one or more embodiments, the IPP
has at least 45 percent by weight crystallinity, or in other
embodiments from about 46 to about 50 percent by weight
crystallinity. Blends of atactic polypropylene and isotactic
polypropylene may be used. In yet other embodiments, atactic
polyalpha olefins (APAOs) may be used.
Complementary Flame Retardants
[0061] As mentioned above, the expandable graphite may be used in
conjunction with a complementary flame retardant. Flame retardants
may include any compound that increases the burn resistivity,
particularly flame spread such as tested by UL 94 and/or UL 790, in
the polymeric compositions of the present invention. Generally,
useful flame retardants include those that operate by forming a
char-layer across the surface of a specimen when exposed to a
flame. Other flame retardants include those that operate by
releasing water upon thermal decomposition of the flame retardant
compound. Useful flame retardants may also be categorized as
halogenated flame retardants or non-halogenated flame
retardants.
[0062] Exemplary non-halogenated flame retardants include magnesium
hydroxide, aluminum trihydrate, zinc borate, ammonium
polyphosphate, melamine polyphosphate, and antimony oxide
(Sb.sub.2O.sub.3). Magnesium hydroxide (Mg(OH).sub.2) is
commercially available under the tradename Vertex.TM. 60, ammonium
polyphosphate is commercially available under the tradename
Exolite.TM. AP 760 (Clarian), which is sold together as a polyol
masterbatch, melamine polyphosphate is available under the
tradename Budit.TM. 3141 (Budenheim), and antimony oxide
(Sb.sub.2O.sub.3) is commercially available under the tradename
Fireshield.TM..
[0063] Examples of other complementary calcium borate, magnesium
hydroxide, basic magnesium carbonate, aluminum trihydrate, zinc
borate, gypsum, and mixtures thereof. In these or other
embodiments, the complementary flame retardant includes colemanite,
which is a borate mineral that is believed to include about 50-80%
calcium borate.
Tackifier Resin
[0064] In one or more embodiments, the asphaltic component may
include tackifier resins. These resins include, but are not limited
to, petroleum resins, synthetic polyterpenes, resin esters and
natural terpenes, and combinations thereof. In certain embodiments,
the resin modifiers soften or become liquid at temperatures of
about 40.degree. C. to about 150.degree. C. In certain embodiments,
the resin modifiers have number average molecular weights, as
measured by vapor phase osmometry, below that of the polymeric
material included in the polymeric film. In certain embodiments,
the number average molecular weights of the resin modifiers are
less than about 5,000. In other embodiments, the number average
molecular weights of the resin modifiers are less than about 1,000.
In additional embodiments, the number average molecular weights of
the resin modifiers are from about 500 to about 1000.
[0065] In certain embodiments, the resin modifiers have ring and
ball softening point of about 20.degree. C. to about 160.degree. C.
In additional embodiments, resin modifiers have ring and ball
softening points of about 40.degree. C. to about 160.degree. C. In
still other embodiments, resin modifiers have ring and ball
softening points of about 50.degree. C. to about 160.degree. C.
[0066] Various types of natural and synthetic resins, alone or in
admixture with each other, may be used be selected as the resin
modifier. Suitable resins include, but are not limited to, natural
rosins and rosin esters, hydrogenated rosins and hydrogenated rosin
esters, coumarone-indene resins, petroleum resins, polyterpene
resins, and terpene-phenolic resins. Specific examples of suitable
petroleum resins include, but are not limited to, aliphatic
hydrocarbon resins, hydrogenated aliphatic hydrocarbon resins,
mixed aliphatic and aromatic hydrocarbon resins, hydrogenated mixed
aliphatic and aromatic hydrocarbon resins, cycloaliphatic
hydrocarbon resins, hydrogenated cycloaliphatic resins, mixed
cycloaliphatic and aromatic hydrocarbon resins, hydrogenated mixed
cycloaliphatic and aromatic hydrocarbon resins, aromatic
hydrocarbon resins, substituted aromatic hydrocarbons, and
hydrogenated aromatic hydrocarbon resins. As used herein,
"hydrogenated" includes fully, substantially and at least partially
hydrogenated resins. Suitable aromatic resins include aromatic
modified aliphatic resins, aromatic modified cycloaliphatic resin,
and hydrogenated aromatic hydrocarbon resins. Any of the above
resins may be grafted with an unsaturated ester or anhydride to
provide enhanced properties to the resin. For additional
description of resin modifiers, reference can be made to technical
literature, e.g., Hydrocarbon Resins, Kirk-Othmer, Encyclopedia of
Chemical Technology, 4th Ed. v.13, pp. 717-743 (J. Wiley &
Sons, 1995).
[0067] In one or more embodiments, the tackifier resins include
phenol-based resins. Included among the phenol-based resins are
phenolic resins. These resins may include reactive phenol resins
(also referred to as functionalized phenol resins), as well as
unreactive resins. In one or more embodiments, the phenolic resin
is a resole resin, which can be made by the condensation of alkyl,
substituted phenols, or unsubstituted phenols with aldehydes such
as formaldehyde in an alkaline medium or by condensation of
bi-functional phenoldialcohols. In one or more embodiments, this
condensation reaction occurs in the excess or molar equivalent of
formaldehyde. In other embodiments, the phenolic resin may be
formed by an acid-catalyzed reaction.
[0068] In one or more embodiments, the tackifier resin is a
polybutene polymer or oligomer. In particular embodiments,
polybutene oils are employed. Useful polybutene oils include
high-viscosity oils that may be characterized by a viscosity at
100.degree. C. of at least 80 cst, in other embodiments at least
100 cst, or in other embodiments at least 120 cst up to, for
example, about 700 or 800 cst. In these or other embodiments, the
high viscosity polybutene oils may be characterized by a molecular
weight of at least 1000 g/mole, in other embodiments at least 1200
g/mole, or in other embodiments at least 1300 g/mole up to, for
example, 1400 or 1500 g/mole. An exemplary high-viscosity
polybutene oil is available under the tradename Indapol H300
(Ineos) or PB32 (Soltex).
Other Constituents
[0069] In one or more embodiments, the asphaltic component may
include oil, which may also be referred to as processing oil or
extender oil. These extenders may include high-boiling
hydrocarbons. Examples of these oils include paraffinic oils,
aromatic oils, naphthenic oils, vegetable oils, and low PCA oils
including MES, TDAE, and SRAE, and heavy naphthenic oils, and
various synthetic oils such as, but not limited, polybutene oils.
In one or more embodiments, the oil employed is selected based upon
its compatibility with the rubber, as well as its ability to
provide advantageous properties to the final composition (e.g.,
green strength or tack). In these or other embodiments, the
asphaltic component may also include fillers, extenders,
antioxidants, waxes, antiozonants, and the like. Useful fillers
include, but are not limited to, inorganic fillers such as calcium
carbonate (i.e. limestone) and glass, such as glass beads.
Amounts
[0070] In one or more embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes at least 0.5, in
other embodiments at least 1, in other embodiments at least 3 and
in other embodiments at least 5 parts by weight expandable graphite
per 100 parts by weight asphalt binder. In these or other
embodiments, the asphaltic component of the asphaltic sheet of the
present invention includes at most 40, in other embodiments at most
30, and in other embodiments at most 20 parts by weight expandable
graphite per 100 parts by weight asphalt binder. In one or more
embodiments, the asphaltic component of the asphaltic sheet of the
present invention includes from about 0.5 to about 40, in other
embodiments from about 1 to about 30, and in other embodiments from
about 3 to about 20 parts by weight expandable graphite per 100
parts by weight asphalt binder.
[0071] In one or more embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes at least 0.5, in
other embodiments at least 1, in other embodiments at least 3, and
in other embodiments at least 5 parts by weight polymeric modifier
per 100 parts by weight asphalt binder. In these or other
embodiments, the asphaltic component of the asphaltic sheet of the
present invention includes at most 40, in other embodiments at most
30, and in other embodiments at most 20 parts by weight polymeric
modifier per 100 parts by weight asphalt binder. In one or more
embodiments, the asphaltic component of the asphaltic sheet of the
present invention includes from about 0.5 to about 40, in other
embodiments from about 1 to about 30, and in other embodiments from
about 3 to about 20 parts by weight polymeric modifier per 100
parts by weight asphalt binder.
[0072] In one or more embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes at least 0.5, in
other embodiments at least 1, in other embodiments at least 3, and
in other embodiments at least 5 parts by weight complementary flame
retardant per 100 parts by weight asphalt binder. In these or other
embodiments, the asphaltic component of the asphaltic sheet of the
present invention includes at most 40, in other embodiments at most
30, and in other embodiments at most 20 parts by weight
complementary flame retardant per 100 parts by weight asphalt
binder. In one or more embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes from about 0.5 to
about 40, in other embodiments from about 1 to about 30, and in
other embodiments from about 3 to about 20 parts by weight
complementary flame retardant per 100 parts by weight asphalt
binder.
[0073] In one or more embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes at least 0.5, in
other embodiments at least 1, in other embodiments at least 3, and
in other embodiments at least 5 parts by weight tackifier resin per
100 parts by weight asphalt binder. In these or other embodiments,
the asphaltic component of the asphaltic sheet of the present
invention includes at most 40, in other embodiments at most 30, and
in other embodiments at most 20 parts by weight tackifier resin per
100 parts by weight asphalt binder. In one or more embodiments, the
asphaltic component of the asphaltic sheet of the present invention
includes from about 0.5 to about 40, in other embodiments from
about 1 to about 30, and in other embodiments from about 3 to about
20 parts by weight tackifier resin per 100 parts by weight asphalt
binder.
[0074] In one or more embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes at least 0, in
other embodiments at least 5, in other embodiments at least 10, and
in other embodiments at least 20 parts by weight filler other than
flame retardant material per 100 parts by weight asphalt binder. In
these or other embodiments, the asphaltic component of the
asphaltic sheet of the present invention includes at most 350, in
other embodiments at most 100, in other embodiments at least 70, in
other embodiments at least 50, and in other embodiments at most 40
parts by weight filler other than flame retardant material per 100
parts by weight asphalt binder. In still other embodiments, the
asphaltic component of the asphaltic sheet of the present invention
includes from 0 to 350, in other embodiments from 1 to 100, and in
other embodiments from 5 to 45 parts by weight filler other than
flame retardant material per 100 parts by weight asphalt
binder.
[0075] In one or more embodiments, the expandable graphite,
complementary flame retardant, and filler may be referred to as
dispersed solids within a matrix of the asphalt material (which for
purposes of this definition includes the asphalt material plus
other non-solid constituents such as the polymer modifier and/or
tackifier). The asphaltic binder, therefore, is the continuous
phase in which the solids are dispersed. In one or more
embodiments, the asphaltic binder is a major volume fraction of the
particle/matrix system. In these or other embodiments, the
asphaltic binder is a major weight fraction of the particle/matrix
system. In one or more embodiments, the weight ratio of asphaltic
binder to solids dispersed in the binder is at least 0.4:1, in
other embodiments at least 0.6:1, in other embodiments at least
0.7:1 in other embodiments at least 0.8:1, in other embodiments at
least 1:1, in other embodiments at least 1.2:1, in other
embodiments at least 1.5:1, in other embodiments at least 2:1, in
other embodiments at least 2.5:1, and in other embodiments at least
3:1.
Method of Making Sheet
[0076] In one or more embodiments, the asphaltic sheet of the
present invention may generally be prepared by using conventional
techniques for forming asphaltic sheet. For example, the technique
may include, in certain embodiments, saturating a reinforcing
textile with a molten asphalt composition. The step of saturating
the sheet may include submerging the reinforcing sheet into a bath
of molten asphalt. In other embodiments, the step of saturating the
sheet may include spraying, roll coating, or otherwise applying a
molten asphalt composition to a reinforcing sheet. Where a
reinforcing sheet is not employed, a molten asphalt material can be
applied to release paper or film and then processed into a sheet
that is devoid of reinforcing scrim.
[0077] In certain embodiments, the molten asphalt composition is
prepared by introducing the expandable graphite to a molten asphalt
composition. In one or more embodiments, the temperature of the
molten asphalt composition at the time of introduction of the
expandable graphite is less than 270.degree. C., in other
embodiments is less than 230.degree. C., in other embodiments less
than 220.degree. C., in other embodiments less than 210.degree. C.,
in other embodiments less than 200.degree. C., in other embodiments
less than 190.degree. C., in other embodiments less than
185.degree. C., in other embodiments less than 175.degree. C., in
other embodiments less than 165.degree. C., in other embodiments
less than 155.degree. C., and in other embodiments less than
145.degree. C. In these or other embodiments, the temperature of
the molten asphalt composition at the time of introduction of the
expandable graphite is at least 125.degree. C., in other
embodiments at least 140.degree. C., in other embodiments at least
150.degree. C., in other embodiments at least 160.degree. C., and
in other embodiments at least 170.degree. C. In one or more
embodiments, these temperatures are maintained during mixing and
processing in the presence of the expandable graphite.
[0078] In one or more embodiments, the molten asphalt composition
is prepared in a multi-stage process whereby the asphalt binder and
optionally one or more additional ingredients (e.g. polymer
modifier), other than the expandable graphite, are mixed at
elevated temperatures up to, for example, 250.degree. C., in other
embodiments up to 240.degree. C., in other embodiments up to
230.degree. C., in other embodiments up to 220.degree. C., and in
other embodiments up to 210.degree. C. Following this initial mix,
the asphaltic composition is cooled below 200.degree. C., in other
embodiments below 190.degree. C., and in other embodiments below
than 185.degree. C., in other embodiments below 175.degree. C., in
other embodiments below 165.degree. C., in other embodiments below
155.degree. C., and in other embodiments below 145.degree. C.
[0079] In one more embodiments, cooling of the asphalt may take
place my adding additional asphalt to the mixture, where the
temperature of the added asphalt is cooler then the asphalt heated
and mixed in the first step. For example, asphalts are typically
flowable at temperatures as low as about 130.degree. C. to about
150.degree. C. Accordingly, asphalt having a temperature of about
130.degree. C. to about 150.degree. C. can be added to the asphalt
mixture prepared in the first mixing step to quickly and
homogeneously cool the asphalt.
[0080] Following the cooling step, the expandable graphite is
introduced to the molten asphalt composition and mixed at
temperatures of less than 200.degree. C., in other embodiments less
than 190.degree. C., in other embodiments less than 185.degree. C.,
in other embodiments less than 175.degree. C., in other embodiments
less than 165.degree. C., in other embodiments less than
155.degree. C., and in other embodiments less than 145.degree.
C.
[0081] In an exemplary process, a reinforcing sheet, which may be
in the form of a planar sheet and may be provided in the form of a
roll, is provided. In one or more embodiments, reinforcing sheet
may be a scrim, or fiberglass mesh sheet, as is known in the art.
Useful scrims include those that are commercially available. For
example, fiberglass scrims are available under the trade name
STYLE.TM. 930120 (Milliken & Co.; Spartanburg, S.C.) and also
available from J. P. Stevens (Greenville, S.C.). In other
embodiments, reinforcing sheet may be an organic felt or a
combination polyester and glass mat. Useful polyester mats are
available from Freudenberg & Co. of Germany. In one or more
embodiments, the asphalt coater may be a reservoir of hot liquid
asphalt. In other embodiments, the asphalt coater may include
spraying apparatus to coat the reinforcing sheet with liquid
asphalt. In yet other embodiments, reinforcing sheet may be coated
with hot liquid asphalt by any alternative methods known to persons
having ordinary skill in the art.
[0082] In one or more embodiments, the reinforcing sheet is drawn
through an asphalt coater, which applies hot liquid (i.e. molten
asphalt) to the reinforcing sheet to create a sheet that is
saturated with asphalt. As noted above, the asphalt composition
includes may include polymeric modifiers, fillers, and other
ingredients conventionally employed with asphalt compositions.
[0083] In one or more embodiments, the asphalt composition may
include the expandable graphite according to the practice of this
invention. In other words, the expandable graphite is added to the
molten asphalt composition prior to the introduction of the
reinforcing sheet to the molten asphalt. Also included within the
molten asphalt may be complementary flame retardant and other
ingredients mentioned above.
[0084] In other embodiments, the molten asphalt composition is
devoid or substantially devoid of expandable graphite. In these
embodiments, the expandable graphite is incorporated into the
asphaltic sheet downstream of the bath or reservoir of molten
asphalt. For example, the expandable graphite can be dropped onto
the sheet after leaving the coater.
[0085] In yet other embodiments, the expandable graphite is
included in the molten asphalt composition prior to the
introduction of the reinforcing sheet to the molten asphalt and the
expandable graphite is incorporated into the asphaltic sheet
downstream of the bath or reservoir of molten asphalt (e.g. by
dropping).
[0086] In one or more embodiments, expandable graphite particles
are dropped on to a sheet that has been coated with molten asphalt,
wherein the asphalt may or may not include expandable graphite.
These particles are dropped at a rate and amount to create at least
a partial layer of expandable graphite particles adjacent to the
asphalt of the coated asphalt sheet. In one or more embodiments,
the act of dropping the expandable graphite particles on to a
coated sheet may at least partially embed some of the graphite
particles in to the asphalt such that the asphalt serves as a
binder to hold the graphite particles in place. In these or other
embodiments, one or more of the plurality of expandable graphite
particles are adhered to the surface of the coated asphalt sheet by
way of the adhesive properties of the asphalt material. In one or
more embodiments, the step of dropping the expandable graphite
creates a concentration gradient of the expandable graphite and the
asphalt.
[0087] In one or more embodiments, the process of dropping
expandable graphite particles on to an asphaltic sheet takes place
after the asphaltic sheet is prepared from a molten asphalt
composition and prior to a substantial cooling of the asphalt
material so as to take advantage of the adhesive properties of the
asphalt. In one or more embodiments, at least a portion of the
expandable graphite particles are dropped on or otherwise applied
to the coated asphalt sheet within 15 seconds, in other embodiments
within 10 seconds, and in other embodiments within 5 seconds of the
asphaltic sheet being prepared (e.g., removal of the asphaltic
sheet from a molten bath in which the asphaltic sheet is prepared).
In one or more embodiments, the expandable graphite is dropped on
the asphaltic sheet prior to solidification of the asphalt material
(e.g. prior to the asphaltic sheet cooling to a temperature below
about 85.degree. C.
[0088] In one or more embodiments, the expandable graphite
particles are applied to the surface of an asphaltic sheet using a
multi-stage process. For example, a multi-stage process may include
multiple drops of graphite particles. In certain embodiments, the
various stages or drops can be configured to achieve certain
characteristics. For example, different sized expandable graphite
particles can be dropped at different stages in order to achieve
desirable coverage of the surface of the asphaltic sheet.
[0089] In one or more embodiments, additional asphaltic material
applied to the sheet after application of the expandable graphite
(e.g. after dropping the expandable graphite onto the sheet, which
can form the layer of expandable graphite or concentrated region of
expandable graphite). This may take place by using curtain coating
or roll coating techniques. In other embodiments, the expandable
graphite is dropped onto the hot asphaltic sheet prior to the sheet
being calendered or sized within a nip roll. As a result, then the
sheet is calendered or sized within a nip roll, the excess
asphaltic material at the nip roll will serve to form a layer (or
skin) of asphaltic material over the layer of expandable
graphite.
[0090] In certain embodiments, a polymeric layer is applied to the
asphaltic sheet after application of the expandable graphite
particles. For example, following one or more drops or applications
of the expandable graphite particles to a surface of the asphaltic
sheet, a polymeric film may be applied over the expandable graphite
particles. In one or more embodiments, this may facilitate
subsequent calendaring of the asphaltic sheet carrying the
expandable graphite particles. In other embodiments, the layer of
expandable graphite particles may be modified by the application of
a release agent, such as sand, silica, or talc, over the expandable
graphite particles. The presence of release agents may, like the
polymeric film, facilitate subsequent calendaring of the asphaltic
sheet.
[0091] In one or more embodiments, the asphaltic sheet may be drawn
through a cooling station to cool the hot asphalt and create a more
stable substrate for the application of granules. In one or more
embodiments, the cooling station may include a water reservoir
through which the asphaltic sheet is drawn. In certain embodiments,
the asphaltic sheet may float across a water reservoir to cool the
sheet while allowing the top surface to retain a higher temperature
than the bottom surface. In other embodiments, the cooling station
may include other cooling mechanisms known to those skilled in the
art.
INDUSTRIAL APPLICABILITY
[0092] In one or more embodiments, the asphaltic sheet of the
present invention may be used as an underlayment. For example, the
sheet may be employed as an underlayment within a metal roofing
system. In one or more embodiments, the metal roofing system may
include a roof deck, an optional insulation layer, the underlayment
of the present invention, and metal panels, which may also be
referred to as metal cladding. In other embodiments, the asphaltic
sheet of the present invention may be employed as an underlayment
within a tile roofing system. In one or more embodiments, the tile
roofing system may include a roof deck, an optional insulation
layer, the underlayment of the present invention, and roofing
tiles.
[0093] Practice of the present invention is not necessarily limited
by the type of roof deck. For example, the roof deck may include a
flat roof, a low-slope roof, or a high-slope roof. The deck may be
fabricated from wood, metal, concrete, or any material useful for
fabricating a roof deck.
[0094] As is known in the art, the insulation layer may include
insulation boards such as polyisocyanurate or polystyrene
insulation boards. These insulation boards may be secured to the
roof deck using known techniques, such as adhesive bonding or
mechanical fastening.
[0095] In one or more embodiments, the underlayment may be applied
directly to the roof deck and the insulation boards can be applied
over the underlayment. In other embodiments, the underlayment may
be applied over the optional insulation layer. Where an insulation
layer is not present, the underlayment may be applied directly to
the deck.
[0096] In one or more embodiments, the metal panels or tile are
then secured to the roof on top of the underlayment. Where the
insulation board is applied over the underlayment, the metal panels
or tiles may be secured over the insulation layer using known
techniques.
[0097] For example, FIG. 4 shows a building structure 40 having a
roof system 41 including a roof deck 42, an asphaltic sheet 46
according to one or more embodiments of the present invention, and
a weather-resistant covering 48, which may include metal cladding
or tile. An optional insulation layer may be positioned above or
below asphaltic sheet 46. In one or more of the embodiments,
asphaltic sheet 46 may operate as an underlayment in roofing system
41.
[0098] In other embodiments, the asphaltic sheet of the present
invention may be used as a barrier sheet, which may also be
referred to as a material. These barrier materials may include air
barriers, which are employed to prevent or reduce the flow of
oxygen and nitrogen into and/or out of a building structure. In
other embodiments, these barrier materials may include vapor
barriers, which are employed to prevent or reduce the flow of water
vapor into and/or out of a building structure. In yet other
embodiments, these barrier materials include moisture barriers,
which are employed to prevent or reduce the flow of moisture (i.e.
liquid water) into and/or out of a building structure.
[0099] For example, FIG. 5 shows a building structure 50 having a
flat roof system 51 including roof deck 52, asphaltic sheets 58
according to embodiments of the present invention, insulation layer
54, and weather-resistant layer 56. Asphaltic sheet 58, which may
operate as a vapor barrier, may be above or below insulation layer
54.
[0100] In one or more embodiments, the barrier sheet may be applied
to a vertical surface (such as a wall) of a building structure.
Using conventional techniques, the barrier may be applied to the
exterior surface of a building structure prior to application of
the external sheathing, such as metal wall panels, brick, composite
siding, wood siding, or vinyl siding.
[0101] For example, FIG. 6 shows a building structure 60 having a
wall system 62 including structural supports 63, insulation layer
64, asphaltic sheet 66 according to embodiments of the present
invention, and exterior cladding 68. Asphaltic sheet 66, which may
operate as a vapor barrier in the wall system, may be positioned on
the interior or exterior of insulation layer 64.
[0102] In still other embodiments, the asphaltic sheet may be used
as a roofing membrane. For example, the asphaltic sheet may be used
as a base sheet or cap sheet in an asphaltic roofing membrane
system. In one or more embodiments, these asphaltic membranes are
modified asphaltic membranes of the type known in the art. Examples
of these membranes, albeit without the expandable graphite, are
shown in U.S. Pat. Nos. 6,492,439, 6,486,236, 4,835,199, 7,442,270,
7,146,771, 7,070,843, 4,992,315, and 6,924,015, which are
incorporated herein by reference.
Characteristics of Asphaltic Sheet
[0103] In one or more embodiments, the present invention provides a
metal roofing system or tile roofing system wherein the asphaltic
sheet of one or more embodiments of the present invention is
employed as an underlayment, and the roofing system is
characterized as a Class A roofing system pursuant to UL and/or
ASTM classifications; this is in fact true where a single layer of
the asphaltic sheet employed within the roofing system as the sole
fire barrier. In one or more embodiments of the present invention,
the asphaltic sheets of the present invention can be used in a
roofing system that can meet the performance standards of the
Burning Brand test of UL 790. In fact, the roofing system can
include a single sheet of the asphaltic sheets of the present
invention as the sole fire barrier and can meet the performance
standards of the Burning Brand test of UL 790. In other
embodiments, the asphaltic sheet may be used in a wall system to
meet the performance standards of NFPA-285.
[0104] In one or more embodiments, the asphaltic sheet of the
present invention is advantageously moisture resistant and can meet
the requirements of ASTM D1970-09. In these or other embodiments,
the asphaltic sheets are characterized by a water vapor
transmission, as defined by ASTM E96, of less than 1.0, in other
embodiments less than 0.5, in other embodiments less than 0.1, and
in other embodiments less than 0.08 g/hr-m.sup.2.
[0105] In one or more embodiments, the asphaltic sheets of the
present invention are advantageously self-adhering (e.g., can be
self-adhered to a substrate), which properties derive, at least in
part, from the asphaltic nature of the matrix in which the other
constituents are dispersed. In certain embodiments, this advantage
is also believed to derive, at least in part, from the amount of
asphalt material present in the sheet relative to the other
constituents of the sheet (e.g., the solid such as filler and flame
retardants). Additionally, the asphaltic sheet of certain
embodiments is advantageously self-sealing; in other words, the
sheet can form a water-tight seal around nail holes and the like.
Again, the advantage is believed to derive from the level of
asphaltic material present in the sheet of certain embodiments.
[0106] In order to demonstrate the practice of the present
invention, the following examples have been prepared and tested.
The examples should not, however, be viewed as limiting the scope
of the invention. The claims will serve to define the
invention.
EXPERIMENTAL
Samples 1-4
[0107] Laboratory-scale asphaltic membranes were prepared by
employing the ingredients set forth in Table I, which shows the
ingredients in percent by weight. The membranes were then subjected
to burn tests, and the results of those tests are likewise provided
in Table I.
[0108] The membranes were formed by first preparing an asphaltic
mixture and then fabricating a membrane from the mixture. The
fabrication technique included embedding a glass scrim into the
membrane. Specifically, the asphaltic composition was prepared by
heating the asphalt to about 300.degree. F. and then adding the SBS
copolymers to the molten asphalt under medium to high shear through
the use of a conventional mixing apparatus. Mixing continued for
close to 20 minutes until the mixture appeared to be smooth and
uniform, which was indicative of the fact that the polymers
dissolved. The temperature of the mixture during the process peaked
at around 340-380.degree. F. Following the addition of the SBS
copolymers, the other fillers (excluding expandable graphite) and
tackifiers were added under similar shear while generally
maintaining the same temperature. The mixture was then allowed to
cool to 300-350.degree. F., and then the expandable graphite was
added while mixing continued for about 2 minutes. Once it was
determined that the graphite was evenly distributed, the membrane
was fabricated. The membrane was generally fabricated by pouring
the mixture on to a release paper on which the glass scrim was
positioned. Spacers were placed at the edges of the release paper
to control the membrane thickness, and a release paper was then
applied over the top of the mixture and pressed to form a flat
membrane. Once the membrane was cooled for sufficient handling, the
test sample was prepared by stapling the membrane to a
4''.times.5'' plywood or OSB board. A thermocouple was sandwiched
between the membrane sample and the wood. The test samples were
then suspended at a 5/12 slope. A propane torch having a 4'' long
flame was positioned so that the tip of the flame was close to the
sample without touching the sample.
TABLE-US-00001 TABLE I Samples 1 2 3 4 Ingredients Asphalt 83.80
81.80 76.10 83.80 Expandable Graphite 3.00 5.00 7.10 0 SBS
Copolymer I 3.40 3.40 4.20 3.4 SBS Copolymer II 3.50 3.50 4.30 3.5
Tackifier 6.30 6.30 8.30 6.3 Burn Test Data Highest Temp. (.degree.
F.) 577.00 576.00 467.00 -- Time @ highest Temp. 4:00 5:00 5:00 --
(Min.) Flow Slow flow, thick Very slow flow, thick No flow, thick
char -- char char Self-extinguishing (Fire 105 5 45 -- out @ Sec)
Exposure of Glass Scrim No No No --
[0109] The asphalt was obtained under the tradename AC-5
(Marathon); SBS I was obtained under the tradename D1184 (Kraton);
SBS II was obtained under the tradename D1118 (Kraton); the
tackifier resin was obtained under the tradename H300 (Ineos); and
the expandable graphite was obtained under the tradename 1721
(Asberry).
[0110] As suggested in Table I, Sample 4 was prepared without
expandable graphite. When subjected to the burn test, this sample
began to burn rapidly and the asphaltic material began to flow
rapidly. As a result, the test had to be terminated within the
first minute for safety reasons. In other words, the sample without
expandable graphite unequivocally failed. In contradistinction,
Samples 1-3 show that the presence of as little as 3 weight percent
graphite withstood the burn test by forming a thick char, which
resulted in little flow of the asphaltic material and ultimately
the fire was self-extinguished within less than 2 minutes of
removal of the flame.
Samples 5-32
[0111] Using procedures similar to those described for samples 1-4,
28 additional samples were prepared wherein colmanite was also
added to the asphaltic mixture, together with expandable graphite.
The specific recipes for each asphaltic membrane is set forth at
Table II, together with the results of the burn tests.
TABLE-US-00002 TABLE II Expandable SBS Sample Asphalt Graphite
colemanite SBS I II Tackifier Flow 5 65.49 4.00 19.50 3.38 3.25
4.39 Very slow flow, thick char 6 75.19 2.60 11.01 3.15 2.56 5.50
little or no flow, thick char (initial heavy flow) 7 76.85 4.00
5.15 4.00 4.00 6.00 Little or no flow, thick char 8 66.00 4.00
20.00 4.00 4.00 2.00 Very slow flow, thick char 9 67.94 4.00 15.56
2.50 4.00 6.00 Very slow flow, thick char 10 80.76 4.00 5.00 2.50
2.54 5.20 Very slow flow, thick char 11 64.37 3.13 20.00 4.00 2.50
6.00 Little or no flow, thick char 12 69.73 2.42 20.00 2.50 3.35
2.00 Slow flow, thick char 13 78.72 4.00 8.73 3.06 3.50 2.00 Slow
flow, thick char 14 83.13 3.38 5.00 4.00 2.50 2.00 Very slow flow,
thick char 15 67.94 4.00 15.56 2.50 4.00 6.00 Slow flow, thick char
16 70.87 4.00 18.13 2.50 2.50 2.00 Very slow flow, thick char 17
64.37 3.13 20.00 4.00 2.50 6.00 Little or no flow, thick char 18
73.99 2.21 12.59 4.00 3.22 3.99 Slow flow, thick char 19 81.27 2.82
5.00 2.91 4.00 4.00 Slow flow, char 20 82.28 1.00 9.27 2.50 2.95
2.00 Heavy flow, drip 21 64.82 1.63 20.00 3.56 4.00 6.00 medium
flow, char 22 82.00 1.00 5.00 4.00 2.50 5.50 Heavy flow, drip 23
69.07 1.00 20.00 2.50 2.50 4.93 Heavy flow, drip 24 75.65 1.00
13.46 2.50 4.00 3.39 Heavy flow, drip 25 84.36 1.00 5.00 3.73 3.91
2.00 Heavy flow, drip 26 71.90 1.00 15.98 2.63 2.50 6.00 medium
flow, dripped some 27 73.09 1.00 18.02 3.39 2.50 2.00 Heavy flow,
drip 28 87.00 1.00 5.00 2.50 2.50 2.00 Heavy flow, drip 29 84.36
1.00 5.00 3.73 3.91 2.00 Heavy flow, drip 30 79.00 1.00 7.17 2.83
4.00 6.00 Heavy flow, drip 31 82.00 1.00 5.00 4.00 2.50 5.50 Heavy,
drip 32 82.20 1.00 5.00 2.50 3.30 6.00 Heavy flow, drip
[0112] As should be evident from the data presented in Table II,
the addition of colemanite had negligible impact on the burn
resistivity of the membranes. Instead, and quite unexpectedly, burn
resistivity, as highlighted by the flow of the material during the
burn test, was advantageously impacted by the expandable
graphite.
Samples 33-43
[0113] In an effort to compare the performance of expandable
graphite in the practice of the present invention with other
intumescent materials, 11 additional samples were prepared and
tested. Specifically, each formulation included 81 percent by
weight asphalt, 7 percent by weight SBS copolymer I, 7 percent by
weight limestone, and 5 percent by weight of the flame retardant
identified in Table III. Table III also provides the results of the
burn test performed on each sample.
TABLE-US-00003 TABLE III Total Ingredients Char Flow Dripping Max
Temp Time Time Self Ext. Sample No. Flame Retardant (Yes/No)
(Yes/No) (Yes/No) (.degree. F.) (s) (min) (Yes/No) 33 None N Y Y
950 42 1 Y 34 Expandable Graphite Y N N 1150 240 4 Y 35 Ammonium N
Y Y 1227 44 1 No Polyphosphate I 36 Ammonium N Y Y 1131 60 1 Y
Polyphosphate II 37 Ammonium N Y Y 1385 60 1 Y Polyphosphate III 38
Ammonium N Y Y 1857 60 1 Y Polyphosphate IV 39 Limestone N Y Y 1880
37 1 Y 40 Colemanite N Y Y 1990 38 1 Y 41 Al(OH).sub.3 N Y Y 1858
27 1 Y 42 Mg(OH).sub.2 N Y Y 1365 60 1 No 43 Zinc Borate N Y Y 1512
60 1 No
[0114] The ammonium polyphosphate I was obtained under the
tradename AP 760 (Clariant); the ammonium polyphosphate II was
obtained under the tradename CROS 486 (Budenheim); the ammonium
polyphosphate III was obtained under the tradename CROS 484
(Budenheim); the ammonium polyphosphate IV was obtained under the
tradename CROS C30 (Budenheim); and the zinc borate was obtained
under the tradename FireBrake ZB.
[0115] As should be appreciated from the data within Table III, the
membrane prepared using expandable graphite was the only sample
that could withstand the burn test. Indeed, the test was extended
for the full four minute length. All other samples had to be
extinguished within one minute for safety reasons.
[0116] Various modifications and alterations that do not depart
from the scope and spirit of this invention will become apparent to
those skilled in the art. This invention is not to be duly limited
to the illustrative embodiments set forth herein.
* * * * *