United States Patent [19]
`Howells
`
`US006054178A
`[11] Patent Number:
`[45] Date of Patent:
`
`6,054,178
`Apr. 25, 2000
`
`[54] FABRIC MESH REINFORCED MONOLITHIC
`THERMOPLASTIC MEMBRANE
`
`[75] Inventor: Harvey A. Howells, Richardson, Tex.
`
`[73] Assignee: Serrot International, Inc., Henderson,
`Nev.
`
`2,697,058 12/1954 Lasak .
`2,712,987 7/1955 Storrs et al. .
`2,793,136 5/1957 Root.
`2,794,677 6/1957 Collardin et al. .
`2,804,337 8/1957 Marantz.
`2,909,443 10/1959 Wolinski.
`2,961,335 11/1960 Shepard .
`3,073,528
`1/1963 Wilson et al. .
`3,171,599 3/1965 Rotolico .
`3,415,450 12/1968 Hawk, Sr. .
`[21] Appl. No.: 09/385,705
`3,441,215 4/1969 Cape .
`-
`3,442,454 5/1969 Stenger et al. .
`[22] Filed:
`Aug. 30, 1999
`(List continued on next page.)
`Related U.S. Application Data
`OTHER PUBLICATIONS
`[60] Continuation of application No. 08/698,302, Aug. 15, 1996,
`abandoned, which is a division of application No. 08/391,
`DVS Technical Committee, Working Group, “Plastics,
`441, Feb. 21, 1995, abandoned.
`
`[51] Int. Cl." … Bosp 1.34 Welding and Adhesive Bonding", Tºsting of Welded Joints
`52 U.S. Cl
`427/209; 427/211; 427/398.1;
`of Thermoplastics—Test Methods—Requirements—Report,
`[52] U.S. 4,739s. 1375; 442/43, 4435s 44263
`Mar. 1986, Doc. XVI—491–86, Deutscher Verand for Sch
`[58] Field of Search ..................................... 427/209, 211,
`427/398.1, 398.2, 288; 442/19, 43, 45,
`58, 62. 65
`2 < -3
`
`• 2–2
`
`2
`
`2
`
`2
`
`weisstechnik e.V.
`
`Deutscher Verband Für Schweisstechnik E.V., “Prüfen von
`Schweißverbindungen aus thermoplastischen Kunstoffen,
`Zugversuch”, Jul. 1985, Richtlinie DVS 2203 Teil 2.
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`9/1930 Carlton .
`1,775,631
`1/1934 Dreyfus.
`1,983,349
`2,034,008 3/1936 Taylor.
`2,125,764 8/1938 Benoit .
`2,199,526
`5/1940 McCowen.
`2,220,140 11/1940 Bartling et al. .
`2,386,626
`1/1945 Nadeau et al. .
`2,404,590 7/1946 Nantz.
`2,431,873
`1/1947 Kennelly.
`2,433,515 12/1947 Jahoda .
`2,436,335
`2/1948 Simonsen .
`2,523,037 9/1950 Mathes .
`2,536,657
`1/1951 Reese .
`2,544,259 3/1951 Duccini et al. .
`2,559,893
`7/1951 Nadeau et al. .
`2,566,441
`9/1951 Camras .
`2,594,222 4/1952 Sandora et al. .
`2,643,955 6/1953 Powers et al. .
`2,653,113 9/1953 Banigan .
`2,678,285 5/1954 Browning .
`2,689,801
`9/1954 D'Alelio .
`
`
`
`-
`-
`-
`Primary Examiner—Elizabeth M. Cole
`Attorney, Agent, or Firm—William G. Lane, Esq.
`[57]
`ABSTRACT
`A method of manufacturing a fabric mesh reinforced mono
`lithic thermoplastic membrane. The open mesh fabric is
`drawn into the gap between two calender rollers of a
`membrane extruder, a molten first thermoplastic material is
`extruded into the throat of the gap between the first roller
`and the first side of the fabric mesh, while a second molten
`thermoplastic material is simultaneously extruded into the
`throat of the gap between the second roller and the second
`side of the fabric mesh. The composite material is then
`drawn through the gap between the first and second rollers
`to force the molten first and second thermoplastic materials
`into and through the open mesh of the fabric to fuse and
`bond the molten first and second thermoplastic materials in
`and about the fabric mesh to form the fabric mesh reinforced
`monolithic thermoplastic membrane.
`
`20 Claims, 1 Drawing Sheet
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`6,054,178
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`
`U.S. PATENT DOCUMENTS
`3,460,764 8/1969 Walli
`2 * > -->
`all IS .
`3,565,345
`2/1971 Moltzan .
`º º º
`3,973,059 8/1976 Brown et al. .
`4,048,419 9/1977 Frese et al. .
`4,087,577 5/1978 Hendrickson ........................... 428/110
`4,096,016 6/1978 Pohl .
`4,239,797 12/1980 Sachs .
`4,278,483
`7/1981 Mansolillo .
`4,327,130 4/1982 Pipkin ..................................... 427/209
`4,368,846
`1/1983 Rau et al. .
`4,439,385 3/1984 Kuhls et al. .
`
`4,488,918 12/1984 Jofs.
`4,501,783 2/1985 Hiragami et al. .
`4,543,106 9/1985 Parekh .
`4608287 ..º. º
`4,623,589 11/1986 Simmonds, Jr. .
`4,632,309 12/1986 Reimer.
`4,666,761
`5/1987 Stamper et al. ........................ 428/215
`4,788,088 11/1988 Kohl .
`4.885,201 12/1989 Brandt.
`4,934,595 6/1990 Reimer.
`5,075,135 12/1991 Brandt.
`5,139,853 8/1992 Mathieson .
`5,167,895 12/1992 Lueghamer.
`5,258,217 11/1993 Lewis.
`
`BESTWAY EXHIBIT 1015-0002
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`

`U.S. Patent
`US. Patent
`
`Apr. 25, 2000
`Apr. 25, 2000
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`6,054,178
`6,054,178
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`BESTWAY EXHIBIT 1015-0003
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`|PR2017-O‘|655
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`BESTWAY EXHIBIT 1015-0003
`IPR2017-01655
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`

`

`1
`FABRIC MESH REINFORCED MONOLITHIC
`THERMOPLASTIC MEMBRANE
`
`2
`These and other objects of the present invention are set
`forth below.
`
`6,054,178
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`FIELD OF THE INVENTION
`This application is a continuation of U.S. patent applica
`tion Ser. No. 08/698,302, filed Aug. 15, 1996, now
`abandoned, which is a divisional application of abandoned
`U.S. patent application Ser. No. 08/391,441, filed Feb. 21,
`1995.
`This invention is directed to a open mesh fabric reinforced
`monolithic thermoplastic membrane which can be used as a
`roofing membrane, or as a liner for ponds, reservoirs, canals,
`pits and the like.
`BACKGROUND OF THE INVENTION
`For several years, fabric mesh reinforced thermoplastic
`membranes have been available for use as a roofing
`membrane, and pond, reservoir, pits liner, canal and the like.
`The conventional way of making such membranes is to
`extrude molten thermoplastic onto one side of a fabric mesh
`to weld the fabric mesh to one side of the thermoplastic
`membrane. The resulting composite is then heated and a
`second layer of molten thermoplastic is extruded onto the
`other side of the fabric mesh to cover the fabric mesh and to
`weld the second thermoplastic to the first thermoplastic.
`Although this product has been made for a number of
`years, it has not been completely satisfactory. The mem
`brane normally does not have a smooth surface; normally
`both surfaces of the membrane reflect the fabric mesh. The
`membrane is normally rippled and is not entirely flat
`because of the temperature differences between the heated
`first extruded thermoplastic and the molten second extruded
`thermoplastic. The existing membrane is truly a three-ply
`product having a first thermoplastic layer and a second
`thermoplastic layer which are partially welded together with
`a fabric mesh disposed in between. Because of the construc
`tion and method of manufacture, there are ply adhesion
`problems and ply delamination is not unknown. Because of
`the way the existing membranes are manufactured, there is
`little choice regarding the surface finish of the finished
`material.
`It is an object of the present invention to provide a fabric
`mesh reinforced monolithic thermoplastic membrane for use
`as a roofing membrane, and reservoir, pond, canal and pit
`liner.
`A further object of the present invention is to provide a
`fabric mesh reinforced monolithic thermoplastic membrane
`having at least one smooth surface.
`An even further object of the present invention is to
`provide a fabric mesh reinforced monolithic thermoplastic
`membrane that lays flat and is ripple free.
`An additional object of the present invention is to provide
`a fabric mesh reinforced monolithic thermoplastic mem
`55
`brane that is not subject to delamination.
`Another additional object of the present invention is to
`provide a one step method for producing a fabric mesh
`reinforced monolithic thermoplastic membrane.
`An even further additional object of the present invention
`is to provide an improved roofing system employing a fabric
`mesh reinforced monolithic thermoplastic membrane having
`a light reflective surface.
`Still another object of the present invention is to provide
`a liner system for canals, ponds, reservoirs, pits and the like
`comprising a fabric mesh reinforced monolithic thermoplas
`tic membrane that contains carbon black pigment.
`
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`SUMMARY OF THE INVENTION
`The present invention is directed to a fabric mesh rein
`forced monolithic thermoplastic membrane comprising an
`open mesh fabric mesh having a first side and a second side
`and a thermoplastic layer encapsulating the fabric mesh, the
`thermoplastic layer having a first side and a second side, the
`first and second sides of the thermoplastic layer having been
`extruded simultaneously but separately in the molten state
`onto the first and second sides of the mesh fabric,
`respectively, to form a single thermoplastic layer, the ther
`moplastic material striking through, i.e., extending through,
`the open mesh of the fabric mesh and surrounding the mesh
`fibers.
`In one embodiment of the present invention, the fabric
`mesh can be woven mesh. In an alternative embodiment, the
`fabric mesh can be a non-woven mesh. The mesh can be a
`plastic mesh, a natural fiber mesh or a metal mesh. It is not
`essential to the present invention that the thermoplastic
`material actually bond to the surface of the mesh. The mesh
`fibers or strands can be smooth fibers or surface configured
`fibers to get a better grip between the mesh and the ther
`moplastic material. Irregular surface fiber mesh can be
`corrugated, have protrusions or hollows or other irregular
`surface configurations that hold the fabric mesh in the
`thermoplastic material.
`In one of the embodiments of the present invention, the
`thermoplastic material can be a polypropylene based, ther
`moplastic olefin. In one of the preferred embodiments of the
`present invention, the thermoplastic on the first side of the
`membrane will be pigmented with a white pigment, such as
`titanium dioxide, to act as a light reflectant and the second
`side of the thermoplastic layer will be pigmented with
`carbon black.
`The present invention is also directed to a method of
`manufacturing a fabric mesh reinforced monolithic thermo
`plastic membrane which comprises drawing an open mesh
`fabric mesh into the gap between the two calender rollers of
`a membrane extruder, the mesh having first and second
`sides; extruding a molten first thermoplastic into the throat
`of the gap between the first roller and the first side of the
`fabric mesh and simultaneously extruding a molten second
`thermoplastic into the throat of the gap between the second
`roller and the second side of the fabric mesh; and drawing
`the composite of the molten first thermoplastic, the fabric
`mesh and the molten second thermoplastic through the gap
`between the first and second rollers and to force the molten
`first and second thermoplastic into and through the open
`mesh of the fabric mesh to fuse and bond the molten first and
`second thermoplastic and to bond the thermoplastics in and
`about the fabric mesh to form the fabric mesh reinforced
`monolithic thermoplastic membrane.
`In the preferred embodiment of the present invention, one
`of the rollers is cooled to cool the molten second thermo
`plastic to a temperature below the thermoplastic melt tem
`perature. The first roller is heated to a temperature between
`85° and 110°, preferably about 105° C., to heat the molten
`first thermoplastic to improve fusing and bonding of the first
`and second thermoplastic.
`In another preferred embodiment of the present invention,
`the fabric mesh reinforced monolithic thermoplastic mem
`brane is maintained in contact with the first roller as it leaves
`the gap to insure complete fusing of the thermoplastics and
`imprint a finish on the first side of the membrane.
`
`BESTWAY EXHIBIT 1015-0004
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`6,054,178
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`3
`In another preferred step of the present invention, after the
`first side of the membrane leaves the surface of the first
`roller, the second side of the membrane is placed in contact
`with the surface of a third cooling roller to cool the second
`side of the membrane.
`In a further preferred embodiment of the present
`invention, the membrane after contact cooling with the third
`roller is rapidly cooled to ambient temperature with air flow.
`In a preferred embodiment of the present invention, the
`fabric mesh is maintained under slight tension as it is drawn
`into the gap between the first and second rollers to maintain
`the fabric mesh in a substantially plainer configuration.
`In one embodiment of the present invention, the first and
`second rollers are rotated at the same speed. Preferably, the
`rollers are maintained at the same speed that the mesh is
`drawn into the gap between the first and second rollers.
`In an alternative embodiment of the present invention, the
`rollers are rotated at different speeds with respect to each
`other. Preferably at least one roller is rotated at the same
`speed as the mesh fabric is drawn into the gap between the
`first and second rollers.
`In one embodiment of the present invention, the fabric
`mesh is fed into the center of the gap between the first and
`second rollers with equal amounts of first and second
`thermoplastic being extruded into the throat of the extruder.
`In an alternative embodiment of the present invention, the
`mesh is fed into the center of the gap between the first and
`second rollers with a greater amount of first thermoplastic
`being extruded into the throat than the amount of second
`thermoplastic being extruded into the throat.
`In still another embodiment of the present invention, the
`mesh is drawn into the gap off center with equal amounts of
`first and second thermoplastic being extruded into the throat
`of the extruder.
`In an alternative embodiment of the present invention, the
`mesh is drawn into the gap off center with a greater amount
`of first thermoplastic being extruded into the throat than the
`amount of second thermoplastic being extruded into the
`throat.
`In the preferred embodiment of the present invention, the
`first and second thermoplastic are the same thermoplastic
`polymer, however, the first and second thermoplastic may
`have different pigments such as carbon black and titanium
`dioxide. Different thermoplastic materials of different ther
`moplastic polymers may be used in the production of the
`membrane of the present invention as long as the two
`thermoplastic materials can fuse together to form a mono
`lithic structure. If the thermoplastic materials exhibit sub
`stantially different thermal coefficients of expansion, the
`resulting membrane may not be suitable for applications
`where the two sides of the membrane are exposed to
`different temperature gradients because of possible buck
`ling. Preferably the two thermoplastics have similar melt
`indexes.
`The present invention is also directed to a roofing system
`comprising a fabric mesh monolithic thermoplastic roofing
`membrane encapsulating an open mesh fabric mesh rein
`forcing material, the thermoplastic on the top side of the
`membrane containing a light reflective pigment.
`In the preferred embodiment of the roofing membrane, the
`thermoplastic is polypropylene based thermoplastic olefin.
`Preferably the thermoplastic contains a UV absorbent if the
`membrane is for outdoor use. Preferably the top side of the
`roofing membrane contains titanium dioxide pigment as the
`light reflectant pigment. Most preferably, the bottom side of
`the membrane is pigmented with carbon black.
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`The present invention is also directed to a liner material
`for ponds, canals, reservoirs and pits comprising a fabric
`mesh monolithic thermoplastic encapsulating an open mesh
`fabric reinforcing material, the thermoplastic of the mem
`brane containing carbon black pigment.
`Preferably, the thermoplastic material contains a UV
`absorbent. Preferably, the thermoplastic material is polypro
`pylene.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a schematic view of the membrane extrusion
`process of the present invention;
`FIG. 2 is a partial sectional top view of the fabric mesh
`reinforced thermoplastic membrane of the present invention;
`FIG. 3 is a cross sectional view taken along lines 3–3 of
`FIG. 2; and
`FIG. 4 is a cross sectional view taken along lines 4–4 of
`FIG. 2.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`Referring to FIG. 1, the membrane extruder 10 comprises
`a first calender roller 12, a second calender roller 14 and a
`cooling roller 20. A take up roller 22 is provided to reel up
`the membrane 44 as a roll 40. The space between the first
`and second roller is referred to as the roller gap 16 and the
`entrance into the gap is referred to as the throat 18. A first
`die or extruder nozzle 24 is located approximate the first
`roller in front of the throat and a second die or extruder
`nozzle 26 is located approximate the second roller in front
`of the throat.
`Open mesh fabric mesh 30 is drawn into the throat 18
`under slight tension to maintain the open mesh fabric mesh
`in a plainer configuration. The first molten thermoplastic is
`extruded from the first nozzle 24 into the throat between the
`first side 31A of the fabric mesh and the first roller 12.
`Simultaneously, the second molten thermoplastic 34 is
`extruded from the second nozzle 26 into the throat between
`the second side 31B and the second roller 14. The rollers are
`rotated as shown by the arrows to draw the open mesh fabric
`and the extruded thermoplastic into the gap 16 between the
`rollers to force the thermoplastic into the open mesh of the
`open mesh fabric mesh, to fuse the first and second molten
`thermoplastic together and to encapsulate the fabric mesh to
`form the membrane. The membrane is drawn from the gap
`at a speed of 4 to 8 feet per minute, although other speeds
`can be employed. As the membrane leaves the throat, the
`first side of the membrane 45A is kept in contact with the
`surface of the first roller 12 to maintain the temperature of
`the polypropylene membrane above 100° C. to complete the
`fusing of the thermoplastic. The maintenance temperature
`varies for different thermoplastic melting points. The mem
`brane 44 leaves the first roller and moves to the third roller
`20 wherein the second side 45B of the membrane contacts
`the surface of the roller 20 to cool the second side and
`solidify it. The second and third rollers 14 and 20 are cooled
`with ambient temperature water. After leaving the gap and
`until the membrane leaves the third roller, the thermoplastic
`is still in a plastic or soft state, but has set, and can be
`imprinted with surface features if desired. Between the third
`roller 20 and the take up reel 22, the membrane is exposed
`to cooling air to cool the membrane down to ambient
`temperature. The cooled membrane is rolled into a roll 40 for
`transportation and storage.
`The process permits the fabric mesh reinforced thermo
`plastic membrane to be made in a single step and it provides
`
`BESTWAY EXHIBIT 1015-0005
`IPR2017-01655
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`

`

`5
`a means for producing a single layer monolithic membrane
`wherein the reinforcing fabric mesh is fully encapsulated in
`the single layer of thermoplastic. The two extruded thermo
`plastics from the first and second nozzles are fully fused
`together in the gap by the action of the rollers to form a
`single layer. Thus, the membrane cannot delaminate, the
`fabric mesh is fully integral with the layer to provide
`maximum strength and reinforcement, and the fabric mesh
`is fully protected by the thermoplastic layer. In addition,
`because the membrane is prepared in a single step from two
`extruded molten thermoplastics at approximately the same
`temperature and which are cooled at approximately the same
`rate, the resulting membrane lies flat and is not subject to
`rippling like conventional fabric mesh reinforced thermo
`plastic membranes which are prepared in two or more
`Separate steps.
`Virtually any type of thermoplastic can be utilized in the
`present process. Preferably the thermoplastic has a melt
`index of at least 1.0 when tested at 2.14 Kg. at 190° C.
`Thermoplastics with higher melt indexes are less viscous
`when melted and flow easier into and through the open mesh
`that thermoplastics with lower melt indexes. Preferably the
`first and second thermoplastics have similar melt indexes;
`this makes the membrane more amenable to hot air
`weldability—sheets of membrane are frequently welded
`together to form continuous membranes for roofing, lines
`and the like—because both sides of the membrane heat up
`at the same rate. Thermoplastics with melt indexes of 1.0 are
`easier to hot air weld in the field. Polypropylene based
`thermoplastic olefin (a thermoplastic mixture of ethylene,
`propylene, polypropylene and EPR manufactured by
`Himont North America, Inc.) has been found to be very
`suitable because of its thermoplastic properties, its strength
`and its resistance to oxidation and UV. However, other
`thermoplastic polymeric material such as polyethylene,
`polystyrene, ABS, polyester thermoplastic, urethane and
`polyvinyl plastics can also be utilized. The membrane can be
`prepared from two types of thermoplastic polymeric mate
`rial with one type of thermoplastic polymeric material being
`extruded from the first die or extruded nozzle 24 and the
`second thermoplastic polymeric material being extruded
`from the second die or extruder nozzle 26. The two ther
`moplastics must be compatible and must be able to fuse
`together to create the desired membrane. Preferably, the two
`thermoplastics will have similar thermal coefficients of
`expansion so that the resulting membrane will lie flat and not
`ripple.
`The fabric mesh can be made of plastic material such as
`polyester or nylon, natural fibers such as cotton or hemp, or
`metal. A fabric mesh must be employed that has an open
`mesh and that can withstand the temperature of the molten
`thermoplastic during the extrusion process. The fabric mesh
`is thinner than the resulting membrane so that the fabric
`mesh will have a protective coating of thermoplastic on the
`first and second sides of the fabric mesh. The fabric mesh
`can be a woven mesh or a non-woven mesh.
`The membranes are normally prepared in thicknesses of
`from 30 to 100 mils, although thicker membranes may be
`prepared and it may be possible to prepare membranes
`thinner than 30 mils.
`Each of the rollers on the extruder is preferably a powered
`roller. Normally the rollers are run at the same circumfer
`ential speed. However, the first and second rollers may be
`operated at different speeds to yield a particular type of
`finish on the resulting membrane. Preferably, at least one of
`the rollers is rotating at the same circumferential speed as the
`speed that the membrane is being drawn out of the gap of the
`extruder rollers.
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`A particular finish can be applied to the first side of the
`membrane by imparting a particular finish to the surface of
`the first roller. The first roller can be polished, smooth,
`roughened, or imprinted with a particular design, and the
`like, which is imparted into the first side of the membrane
`which is relatively plastic when it leaves the gap 16.
`The size of the rollers does not appear to be crucial to the
`process. Rollers having a diameter of 14" have been found
`to be quite satisfactory although smaller and larger rollers
`would work equally as well. The second and third rollers 14
`and 20 are normally cooled with ambient temperature water;
`and the first roller 12 is heated with water and steam to bout
`105° C. to maintain the temperature of the polypropylene
`based thermoplastic olefin to at least 100° C. The thermo
`plastic is cooled below its melting temperature before it
`leaves contact with the surface of a roller, that is, the first
`side 45A of the membrane of 44 is cooled to below its
`melting temperature before it leaves the surface of the first
`roller 12 and the second side 45B of the membrane is cooled
`to below its melting temperature before it leaves the surface
`of the cooling roller 20.
`Although the open mesh fabric mesh is normally drawn
`into the center of the gap, that is to the middle of the gap 16
`between the first and second rollers, the fabric can be drawn
`off center into the gap. When it is desired to have the fabric
`mesh in the center of the membrane product, normally equal
`amounts of thermoplastic are extruded from the first and
`second nozzles 24 and 26. However, different amounts of
`thermoplastic can be extruded from the first and second
`nozzles to make the first or second side of the membrane
`thicker. Sufficient thermoplastic is employed to fully cover
`the fabric mesh.
`Referring to FIG. 2, the membrane 44 comprises open
`mesh fabric mesh 46 encapsulated by thermoplastic 48. As
`shown in FIG. 3, the lateral mesh fabric fibers or strands 54
`and the longitudinal mesh fabric fibers or strands 56 of the
`open mesh fabric mesh 46 are encapsulated between the first
`side 50 of the thermoplastic membrane 44 and the second
`side 52 of the thermoplastic membrane. Although the open
`mesh fabric mesh is shown in the central region of the
`membrane, the mesh fabric can be located off center depend
`ing upon the particular need.
`The dotted line in FIG. 4 identifies the zone fusion
`between the first extruded thermoplastic and the second
`extruded thermoplastic when equal amounts of thermoplas
`tic are employed in the manufacture of the membrane. The
`two extrusions of thermoplastic are completely fused
`together and there is no line of demarkation in the membrane
`44 if the same thermoplastic is used to produce the mem
`brane. The membrane is a single layer membrane, not a two
`layer membrane. Accordingly, the resulting membrane can
`not be delaminate. It is particularly important during the
`manufacture of the membrane that the extruded thermoplas
`tic be heated to a sufficiently high temperature so that the
`two extrusions of molten thermoplastic can flow into and
`through the open mesh of the open mesh fabric mesh and
`fuse with each other before the melted thermoplastic has
`cooled by the first and second rollers to below its fusion or
`melting temperature. It is only in that way that the mono
`lithic membrane of the present invention can be produced.
`The open mesh fabric membrane can be woven from plastic,
`natural fiber or metal fibers or strands. Alternatively, non
`woven mesh of plastic or metal mesh can also be employed
`in the present invention.
`When the monolithic membrane is to be employed for
`roofing, the first layer 48 will preferably be pigmented with
`
`BESTWAY EXHIBIT 1015-0006
`IPR2017-01655
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`

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`6,054,178
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`a reflective pigment, such as titanium dioxide or particulate
`aluminum metal. Preferably, the second side 52 of the
`membrane 44 will be pigmented with carbon black pigment.
`However, both the first and second side can be pigmented
`with light reflective pigment. If desired, either sides or both
`sides can be pigmented with other colored pigmented mate
`rials for decorative effects. When the monolithic membrane
`is to be used as liners for canals, reservoirs, pits or the like,
`the thermoplastic is normally pigmented with a black pig
`ment such as carbon black. Carbon black is an excellent UV
`10
`absorber and protects the thermoplastic from atmospheric
`oxidation.
`Although not shown in the figures, the surface of either
`the first side 50 or the second side 52, or both sides, can be
`manufactured with different types surface finishes. for rela
`tively thin membranes, the first side can be finished with a
`smooth or brushed finish and the second side normally
`reflects the open mesh fabric.
`The membrane can be prepared with two or more layers
`of open mesh fabric mesh as long as there is sufficient
`spacing between the open meshes to permit the molten
`thermoplastic to enter into and go through the open mesh to
`complete encapsulate the mesh fiber and fuse the two
`extrusions of thermoplastic together.
`What is claimed is:
`1. A method of manufacturing a fabric mesh reinforced
`monolithic thermoplastic membrane having first and second
`sides of thermoplastic comprising drawing an open mesh
`fabric mesh into a throat between parallel, spaced apart first
`and second calender rollers of a membrane extruder, the first
`and second calender rollers separated by a gap, the mesh
`having first and second sides; simultaneously extruding a
`molten first thermoplastic into the throat of the two rollers
`between the first side of the open mesh fabric mesh and the
`first roller and a molten second thermoplastic into the throat
`between the second side of the open mesh fabric mesh and
`the second roller; and drawing the composite of molten first
`and second thermoplastics and the open mesh fabric mesh
`through the gap between the first and second calender rollers
`to force molten first and second thermoplastic into and
`through the open mesh of the fabric mesh to encapsulate the
`open mesh fabric mesh and fuse the first and second molten
`thermoplastic together to form a single layer and to produce
`the fabric mesh reinforced monolithic thermoplastic mem
`brane having first and second sides of thermoplastic, the first
`45
`and second thermoplastics being compatible and fusible
`with each other, the first calender roller heated to maintain
`the temperature of the fabric mesh reinforced monolithic
`thermoplastic membrane above 100° C., the temperature of
`the fabric mesh reinforced monolithic thermoplastic mem
`50
`brane being maintained above 100° C. after being drawn
`from the throat to complete fusing of the thermoplastic by
`keeping the first side of the fabric mesh reinforced mono
`lithic thermoplastic membrane in contact with the first
`calender roller, the second calender roller cooled with ambi
`ent temperature water to cool the second side of the ther
`moplastic of the resulting fabric mesh reinforced monolithic
`thermoplastic membrane to a temperature below the melting
`temperature of the first and second thermoplastics as it
`leaves the gap between the first and second calender rollers.
`2. The method according to claim 1 wherein after con
`tacting the first side of the fabric mesh reinforced monolithic
`thermoplastic membrane on the first roller to complete the
`fusing of the thermoplastics, the second side of the fabric
`reinforced monolithic thermoplastic membrane is contacted
`with the surface of a cooled roller to cool the second side and
`solidify it.
`
`55
`
`60
`
`65
`
`8
`3. The method according to claim 2 wherein the fabric
`mesh reinforced monolithic thermoplastic membrane after
`cooling and solidifying the second side of the membrane on
`the cooled roller is cooled with air to ambient temperature.
`4. The method according to claim 1 wherein the open
`mesh fabric mesh is maintained under slight tension while
`being drawn into the throat to maintain the fabric mesh in a
`substantially planar state.
`5. The method according to claim 1 wherein the first and
`second calender rollers are rotated at the same circumfer
`ential speed.
`6. The method according to claim 1 wherein the first and
`second calender rollers are rotated at different circumferen
`tial speeds.
`7. The method according to claim 1 wherein the open
`mesh fabric mesh is drawn into the center of the gap between
`the first and second calender rollers and equal amounts of
`molten first and second thermoplastic are extruded into the
`throat.
`8. The method according to claim 1 wherein the open
`mesh fabric mesh is drawn into the center of the gap between
`the first and second calender rollers and a greater amount of
`molten first thermoplastic is extruded into the throat than the
`amount of molten second thermoplastic extruded into the
`throat.
`9. The method according to claim 1 wherein the open
`mesh fabric mesh is drawn into the gap between the first and
`second calender rollers closer to the second calender roller
`than to the other roller, and a greater amount of the molten
`first thermoplastic is extruded into the throat than the
`amount of molten second thermoplastic extruded into the
`throat.
`10. The method according to claim 1 wherein open mash
`fabric mesh is drawn into the gap between the first and
`second calender rollers closer to the first calender roller than
`to the other roller and a greater amount of the molten second
`thermoplastic is extruded into the throat than the amount of
`molten first thermoplastic extruded into the throat.
`11. The method according to claim 1 wherein the second
`thermoplastic is cooled below its melting temperature before
`it leaves contact with the second calender roller.
`12. The method according to claim 1 wherein the first
`thermoplastic is cooled below its melting temperature before
`it leaves contact