(12) United States Patent
`Di Pede
`
`USOO6925766 B2
`(10) Patent No.:
`US 6,925,766 B2
`(45) Date of Patent:
`Aug. 9, 2005
`
`(54) MULTILAYER SLIPRESISTANT SHEET
`MATERIAL
`
`(75) Inventor: Sandro Di Pede, Toronto (CA)
`
`(73) Assignee: IBCO Srl (BB)
`- - -
`(*) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 31 days.
`
`(21) Appl. No.: 10/390,757
`(22) Filed:
`Mar. 19, 2003
`(65)
`Prior Publication Data
`
`US 2004/0148887 A1 Aug. 5, 2004
`Foreign Application Priority Data
`(30)
`Feb. 5, 2003 (CA) ............................................. 2418498
`(51) Int. Cl." .................................................. E04D 1/10
`(52) U.S. Cl. .............................. 52/408; 52/177; 52/181
`(58) Field of Search ............................................ 52/408
`(56)
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,054,710 A * 10/1977 Botsolas ...................... 442/31
`4,054,711 A * 10/1977 Botsolas ......
`... 442/31
`4,319,854. A * 3/1982 Marzocchi
`... 404/28
`4.866,897 A
`9/1989 Yount .......................... 52/363
`4992,315 A 2/1991 Zickell et al.
`5,613,332 A * 3/1997 Saylor, Jr. .................... 52/177
`5,687,517 A 11/1997 Wiercinski et al.
`5,693,395 A * 12/1997 Wine ........................... 428/49
`5,787,655 A * 8/1998 Saylor, Jr. .................... 52/181
`
`5.948,505 A * 9/1999 Puppin ....................... 428/121
`6,021,611 A
`2/2000 Wells et al. ................... 52/98
`6,044,598 A
`4/2000 Elsasser et al. ............... 52/181
`6,112,492 A * 9/2000 Wells et al. .................. 52/558
`6,192,650 B1
`2/2001 Kittson et al. ............. 52/741.4
`6,296,912 B1 10/2001 Zickell
`6,308,482 B1 10/2001 Strait
`6,352,754 B1
`3/2002 Frost et al. ................... 428/77
`6,355,333 B1 * 3/2002 Waggoner et al. .......... 428/174
`6,378,259 B1
`4/2002 Carlson
`6,427,395 B1
`8/2002 Elsasser et al. ............... 52/181
`6,715,249 B2
`4/2004 Rusek et al. ............... 52/481.1
`6,745,535 B2 * 6/2004 Nordgren et al. ........ 52/506.01
`FOREIGN PATENT DOCUMENTS
`WO-99/40271 A1
`8/1999
`WO
`WO-01/73242 A1 10/2001
`WO
`2326257 A1
`5/2002
`WO
`* cited by examiner
`Primary Examiner Rodney B. White
`(74) Attorney, Agent, or Firm-Stephen R. Burri; Miller
`Thomson LLP
`ABSTRACT
`(57)
`There is provided a sheet material having a walking Surface
`with high slip resistance. The Sheet material has a flexible
`Structural layer laminated to a mesh layer which has inter
`connected reinforced Strands and protruding nodes to impart
`a high coefficient of friction. The high coefficient of friction
`of the sheet material provides a roofing underlayment which
`is Safe to walk upon in dry, wet or dusty conditions, and on
`Steeply sloped Surfaces. The sheet material may also be used
`as an industrial wrapping material or a fabric.
`
`46 Claims, 3 Drawing Sheets
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`
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`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 1
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`U.S. Patent
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`Aug. 9, 2005
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`Sheet 1 of 3
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`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 2
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`U.S. Patent
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`Aug. 9, 2005
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`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 3
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`Aug. 9, 2005
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`Sheet 3 of 3
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`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 4
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`1
`MULTILAYER SLIP RESISTANT SHEET
`MATERIAL
`
`US 6,925,766 B2
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`TECHNICAL FIELD OF THE INVENTION
`The invention relates to sheet materials. In particular, the
`invention relates to sheet materials for use as roofing
`underlayments, industrial wrapping materials or fabrics.
`BACKGROUND OF THE INVENTION
`In both residential and commercial roofing applications, a
`primary roof covering material provides the main water
`protection barrier. Whether the primary covering is compo
`Sition shingles, metal panels or shingles, concrete or clay
`tiles, wood Shakes, or slate, it is the function of the primary
`roofing material to protect the building interior from water
`ingreSS.
`In Some circumstances, whether due to primary roofing
`material design, installation practices, or accidental breach
`of the primary roofing material, water can penetrate the
`primary roofing material. To protect the building interior in
`these circumstances, it is common to use a Secondary water
`Shedding device called a roofing underlayment which acts as
`a temporary water Shedding device.
`A variety of roofing underlayment products are commonly
`used. The two major classes are mechanically attached and
`Self-adhered underlayments, the latter commonly referred to
`as "peel and Stick.
`It is desirable that a roofing underlayment provide a
`surface which has a sufficiently high coefficient of friction
`(“COF) to be safe for an applicator to walk upon. The
`phrase "high coefficient of friction' in this document means
`a static coefficient of friction of at least 0.8 or a dynamic
`coefficient of friction of at least 0.8. Underlayments should
`be easily affixable to a roofing Surface, for example by
`nailing or adhesion. They should ideally be impermeable to
`moisture. High tensile and tear Strengths are also desirable
`to reduce tearing during application and exposure to high
`winds. Underlayments should be light in weight to facilitate
`ease of transport and application, and should be able to
`withstand prolonged exposure to Sunlight, air and water.
`A common mechanically attached roofing underlayment
`product used in the United States and Europe is bituminous
`asphalt-based felt, commonly referred to as felt. Typically,
`this felt comprises organic paper felt Saturated with asphaltic
`resins to produce a continuous sheeting material which is
`processed into short rolls for application.
`Such felts generally demonstrate good resistance to water
`ingreSS and good walkability in dry and wet roof conditions.
`Disadvantages include very low tensile and tear Strengths,
`relatively high weight per unit Surface area, a propensity to
`dry and crack over time, extreme lack of resistance to
`ultraviolet (“UV”) exposure, high likelihood of wind blow
`off, and a propensity to absorb water causing buckling and
`Wrinkling, thus preventing the application of direct primary
`roofing materials. Such as composition shingles.
`AS felts have very low tensile and tear Strengths, their use
`is generally confined to roofing applications where the
`roofing underlayment is attached directly to a Solid, con
`tinuous roofing deck, rather than in Spaced sheathing appli
`cations where open Spaces characterize the roof structure.
`Use of felts in Spaced sheathing roofs would endanger the
`applicator should the applicator walk over a Section of the
`roof structure covered only by felt.
`In climatic regions where ice damming or prolonged
`exposure to water is prevalent, it is common to employ thick
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`rubberized asphalt-based underlayments in the Valleys,
`eaves, and Seams of the roof. These underlayments are
`generally applied not by mechanical means, but by adhe
`Sives exposed by removing release liners from the bottom
`Surface of the underlayment.
`In Europe, it is common in roofing design to utilize Spaced
`sheathing rather than Solid decking prior to application of
`the primary roof covering materials. To address the Safety
`issue of an applicator falling through rafters, Several prod
`ucts have been marketed with high tensile and tear Strengths
`which are Specifically designed to prevent applicator breach
`during application.
`These materials are generally reinforced membranes Such
`as woven hybrids with other laminates or coatings, or
`reinforced non-woven polymeric Synthetic materials, rather
`than asphaltic felts. They are generally lightweight, thin,
`have high tensile, tear and burst Strengths, and are Superior
`to felts in UV resistance and resistance to drying and
`cracking over time.
`The major drawback of Such underlayments is their low
`COF on the walking surface in dry or wet conditions. This
`problem limits the commercial attractiveness of Such prod
`ucts in high pitch roofs or in climates characterized by
`frequent and Sporadic wet or humid conditions. It has limited
`these products to Spaced sheathing applications where Safety
`and tensile Strength are more important than walkability.
`In many markets, Such as the US and Canada, building
`design is characterized by roofing Structures possessing Solid
`decking Substrates onto which is applied roofing underlay
`ment and, ultimately, the primary roofing material. AS the
`decking Surface provides a safe walking medium for the roof
`applicator, underlayment walkability, that is, the ability to
`permit applicators to walk upon the underlayment without
`Slipping, becomes more important than tensile Strength. Any
`roofing underlayment which does not provide walking Safety
`under dry and wet conditions will be unsafe for use without
`Special precautions, and will be severely limited in com
`mercial market penetration.
`Such underlayments include RoofGuard TM and Roof TOP
`Guard IITM produced by Rosenlew of Finland. These are
`produced using woven tape technology as a reinforcement,
`and are two-sided polymer-coated for encapsulating the
`porous woven substructure. RoofGuardTM utilizes Smooth,
`high COF polymers to improve walkability in dry condi
`tions. However, it suffers dramatic reduction in COF in wet
`conditions.
`In Roof TOPGuard IITM, the walking surface has been
`replaced by a polypropylene Spun bond non-woven layer.
`This Surface provides a slight improvement in walkability in
`Some wet Surface conditions. However, it does not provide
`Safety in highly pitched roofs and very wet conditions. The
`non-woven material also has a tendency to peal or Suffer
`Surface fiber tears under foot load, and does not readily
`absorb or displace water when walked upon. Therefore, this
`product is limited in its ability to compete with felt roofing
`underlayments under wet conditions.
`TRIFLEX 30TM, produced by Flexia Corporation of
`Canada is of Spun bond polypropylene construction, with a
`polypropylene layer coating both sides. The Surface is
`relatively Smooth and Void of any Surface texture properties
`which would provide high COF properties under wet or
`dusty conditions.
`There are other examples of underlayment products, nota
`bly in the self-adhered or “peel and stick” bituminous
`membrane market, which possess various Surface designs
`aimed at improving walkability under wet conditions. Grace
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`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 5
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`US 6,925,766 B2
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`3
`Construction Products produces various rubberized asphalt
`self-adhered products, including SelectTM and Ultra TM, hav
`ing either a grainy polymer film laminate Surface or an
`embossed polymer adhesive pattern as a Surface layer.
`Neither product, however, works well under wet or dusty
`conditions.
`Polyglass produces Polystick PTM and Polystick MUTM
`Self-adhered underlayment with polymer corrugated film
`laminated and non-woven fabric Surfaces. Neither of these
`products workS very well in wet conditions, as there is no
`mechanism to generate high normal and shear forces under
`walking load to resist Slippage.
`Additional mechanical and Self-adhering membrane roof
`ing underlayment products are shown in Table 1, in which
`“M” refers to mechanically applied underlayments and “SA'
`to self-adhered underlayments. All of the abovementioned
`materials, as well as all materials in Table 1, were tested in
`Simulated test roof pitches ranging from a 4:12 pitch (a
`vertical rise of 4 units over a horizontal distance of 12 units)
`to a 12:12 pitch under extremely wet Surface conditions. All
`materials were found to possess Surfaces that become highly
`Slippery and unsafe to walk upon when coated with water.
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`4
`extrusion coating methods, it is normal to use Specially
`Surfaced chilling rolls to quench the molten polymer to
`Solidify the product and reduce thermal damage of the
`reinforcement. The use of hard inorganic particles would
`Severely damage processing equipment, and also signifi
`cantly increase the mass per unit area of the resulting
`underlayment, limiting the advantages inherent in light
`weight Synthetic polymer underlayments.
`Adding hard particles to the throat of an extruder to
`produce granular coatings would not be feasible as it would
`damage the processing equipment. Particles would be
`unable to pass through normal filtration media or narrow die
`Slits. Furthermore, adhesion between inorganic particles and
`thin thermoplastic coatings is generally very poor, permit
`ting the particles to dislodge from the underlayment Surface.
`The use of Specialty inorganic particle coatings could
`improve bonding to the underlayment Surface, but would
`add technical complexity and cost. Also, hard inorganic
`particles may tear and gouge the relatively Soft Surface
`layers of the polymer underlayment if freed from the surface
`and walked upon, thereby permitting water penetration of
`the underlayment.
`
`SUMMARY OF THE INVENTION
`In general terms, the present invention is a polymeric
`multi-layer sheet material that provides a high COF in dry,
`wet or dusty Surface conditions. The sheet material may be
`used for a variety of applications, including as a roofing
`underlayment, as an industrial wrapping material, and as a
`fabric. The high COF is achieved through the use of a noded
`mesh material, laminated to the walking Surface of a struc
`tural layer or rubberized asphalt, Such that the mesh provides
`a Secure Surface for walking even under dusty or wet
`conditions. In this document, the term “laminated” means
`fixedly connected Surface to Surface in a layered relation
`ship.
`The sheet material of the present invention is character
`ized by a structural layer having high tensile and tear
`Strengths, coated with thermoplastic resins. A mesh possess
`ing nodular characteristics and preferably coated on both
`Sides with a tacky coating to provide an enhanced lamination
`to the structural layer and a high COF in dry, wet or dusty
`conditions, is laminated to the upper Surface, and becomes
`the walking Surface in underlayment applications. The mesh
`may be manufactured of plastic, metal, glass, or other
`materials.
`In one of its aspects, the invention is a sheet material
`having a flexible structural layer and a mesh layer laminated
`to the Structural layer, the mesh layer having interconnecting
`Strands and protruding nodes at the junctions of the Strands.
`The sheet material may have a lamination layer laminated
`between the structural layer and the mesh layer. The lami
`nation layer may be made of a polyolefin or a blend of
`polyolefins. The polyolefin may be a low-density polyeth
`ylene or polypropylene. It may be a polymer having a high
`COF.
`The mesh layer may be treated with a tacky or high COF
`coating, which may be ethylene Vinyl acetate copolymer.
`The structural layer may be made of woven polyolefin
`tapes or non-woven polyolefin, or woven or non-woven
`reinforced membrane Substrates Such as polyethylene
`terephthalate, nylon or glass.
`One or more layers of the sheet material or underlayment
`may be lightly coloured to reflect Solar radiation, thereby
`reducing heat absorption of radiant energy transfer into the
`
`TABLE 1.
`
`Roofing underlayment products
`
`25
`
`Type Trade Name
`Supplier
`MFM Building SA Ice Buster TM
`Products
`MFM Building SA Wind & Water
`Products
`Sea TM
`TAMKO
`SA TWTile and
`Metal TM
`SA WIP 200 TM
`M Divoroll Top TM
`M Tyvek Solid TM
`M Roof Shield TM
`
`Miradri
`Lafarge
`Dupont
`Daltex
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`Surface Layer Type
`silver, embossed polymer film
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`black, grainy polymer film
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`blistered surfaced film
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`black, embossed polymer film
`black, non woven fibers
`white, tan, pitted spun bonded
`grey, embossed non woven
`fibers
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`35
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`Wiercinski, in U.S. Pat. No. 5,687,517, describes a roof
`ing underlayment with corrugated ridges in the machine
`direction to achieve Slip resistance in installation on a sloped
`roof. The Surface layer comprises oriented, corrugated film
`laminated onto Substrate. These ridges comprise polymer
`materials having a low COF under dry or wet conditions.
`These ridges do not provide Sufficient shear and normal
`force resistance under loading, as the individual ridges lack
`rigidity and bend over. Such an underlayment does not
`function well under wet conditions.
`Strait, in U.S. Pat. No. 6,308,482, describes a reinforced
`roofing underlayment with a tensile Strength Sufficient to
`resist tearing when exposed to tensile loads from various
`directions. He further discloses provision of a slip-resistant
`polypropylene Sheet on the outer Surface of the roofing
`underlayment.
`Neither of the above patents discloses satisfactory slip
`resistance under wet, humid or dusty conditions at high roof
`pitches between 4:12 and 12:12. Neither discloses an inven
`tion in which the bottom layer is resistant to slippage
`between the underlayment and the deck during installation,
`nor do they combine high tensile Strength and slip resistance
`on both sides of the underlayment.
`One method in the prior art of achieving a high COF
`under wet conditions is by embedding extremely hard,
`granular, inorganic particles into the Surface of asphalt
`bituminous underlayments.
`Polymer underlayments are produced by various forms of
`polymeric extrusion, lamination, or thermal calendaring. In
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`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 6
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`US 6,925,766 B2
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`roof attic space. In this document, the term “lightly
`coloured’ means being of a colour which possesses a total
`solar reflection (ASTM E903-96) of at least 25%. One or
`more layers of the sheet material or underlayment may be
`treated to increase UV resistance, thereby allowing extended
`exposure to the elements without damaging the underlay
`ment. One or more layers may be treated with mold inhibi
`tors to inhibit mold growth on the underlayment and imme
`diate Surrounding roof area. One or more layerS may be
`treated with a fire retardant compound to increase fire
`resistance.
`The sheet material may be used as an underlayment, an
`industrial wrapping material, or a fabric.
`The sheet material may have a high COF coating on the
`lower Surface of the Structural layer.
`In another of its aspects, the invention is a roof under
`layment having a mesh layer with interconnected Strands
`and protruding nodes at the junctions of the Strands, the
`mesh layer laminated to a flexible Structural layer, and a high
`COF film laminated to the lower Surface of the structural
`layer. A first lamination layer may be laminated between the
`mesh layer and the Structural layer and a Second lamination
`layer may be laminated between the Structural layer and the
`high COF film.
`In yet another aspect of the invention, there is provided a
`roof underlayment having a mesh layer with interconnected
`Strands and protruding nodes at the junctions of the Strands,
`a bituminous rubberized asphalt layer laminated to the mesh
`layer, an adhesive layer laminated to the lower Surface of the
`asphalt layer and a release liner releasably laminated to the
`lower Surface of the adhesive layer to produce a Self
`adhering bituminous membrane roofing underlayment pos
`Sessing a mesh layer Surface that is highly walkable in wet
`conditions.
`The sheet material and roof underlayment of the invention
`have a high COF, good walkability on Sloped Surfaces and
`exceptional slip resistance in dry, wet, or dusty conditions.
`In a further aspect of the invention, there is provided a
`roofing underlayment having a top Surface noded mesh layer
`with a high COF in dry, wet or dusty conditions. The
`underlayment has a structural layer with high tensile and tear
`strengths and a bottom surface with a sufficient COF to
`avoid slippage between the underlayment and the deck to
`which the underlayment may be applied.
`Other aspects of the invention will be appreciated by
`reference to the description of the preferred embodiment
`which follows, and to the claims.
`BRIEF DESCRIPTION OF THE DRAWINGS
`Embodiments of the invention will now be described with
`reference to the accompanying figures, in which numerical
`references denote like parts, and in which:
`FIG. 1 is top view of the mesh layer of the invention
`showing the interlaced Strands and nodes of the mesh.
`FIG. 2 is a cross-sectional view of one embodiment of a
`roofing underlayment according to the invention.
`FIG. 3 is a cross-sectional view of a second embodiment
`of a roofing underlayment showing a structural layer lami
`nated to Slip-resistant film.
`FIG. 4 is a cross-sectional view of a third embodiment of
`a roofing underlayment showing a peel-and-Stick treatment.
`FIG. 5 is a cross-sectional view of a fourth embodiment
`of a roofing underlayment showing a Self-adhered bitumi
`nous rubberized asphalt layer.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`Referring to FIG. 1, the multilayer slip-resistant sheet
`material of the present invention, generally indicated by
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`reference numeral 10, has a noded mesh layer 12 having
`interconnected Strands and protruding nodes at the junctions
`of the strands. Preferably, the nodes are significantly thicker
`than the Strands, thus providing the key nodular character
`istics. The mesh layer may be laminated by a Synthetic resin
`lamination layer 13 to a structural layer 11. Alternatively, the
`mesh layer may be laminated directly to the Structural layer,
`for example by existing means of thermal bonding using
`heat and pressure. The Structural layer is preferably a woven
`or non-woven Scrim of Synthetic polymer resin, but other
`materials are possible.
`The sheet material may be used in a roofing underlay
`ment. Referring now to FIG. 2, a roofing underlayment 20
`has a Structural layer 11, preferably a woven Scrim made of
`Synthetic polymer resin tapes, to provide tensile Strength.
`The polyolefin tapes forming the Scrim are fabricated by
`methods well known in the art. Typically, the scrim of the
`structural layer would have 8-64 tapes per decimeter (4-16
`tapes per inch) in the machine direction and 8-64 tapes per
`decimeter (2-16 tapes per inch) in the cross direction. The
`machine direction is the linear direction in which the sheet
`material is manufactured. Other Scrim construction param
`eters are also possible without departing from the Scope of
`the invention.
`A mesh layer 12 is laminated to the upper Surface of the
`structural layer by a synthetic lamination layer 13. The mesh
`layer 12 has nodes protruding from its upper Surface, and
`may be treated with a tacky coating Such as ethyl vinyl
`acetate copolymer (“EVA") which provides an improved
`COF to the Surface.
`The lamination layer 13 may comprise a tacky polymer or
`a blend of tacky polymers. Such tacky polymers should have
`a high COF and may comprise low-density polyethylene,
`polypropylene or another copolymer polyolefin. The under
`layment 20 also may be coated on its lower Surface with a
`tacky non-slip polymeric resin coating 14. Both the lami
`nation layer 13 and the coating 14 provide a membrane to
`prevent moisture passing through the sheet material. One or
`more of the layerS may be treated with additives to increase
`UV resistance, retard fire, reduce heat absorption or reduce
`mold creation.
`Alternatively, the mesh layer may be laminated to the
`Structural layer by other means, including thermal calendar
`ing or application of infrared or microwave energy. In these
`embodiments, no lamination layer is necessary.
`The unusually high COF of the walking surface in wet
`conditions is achieved by a combination of oriented, Stiff,
`laminated mesh Strands having high tensile and Shear
`Strengths, and a unique high COF polymer-coated nodular
`Surface on the mesh material. Water and dust covering the
`underlayment Surface predominantly reside in the Spaces
`between nodes and Strands, and not on the nodes. AS water
`and dust accumulate, they will flow over the Strands and
`reside in the Spacing pockets between the Strands without
`covering the nodes.
`A roofing installer walking on the noded mesh Surface
`will transmit the walking load primarily onto the nodes,
`which are generally free of water and dust. The high
`Strength, oriented nodes have very high normal and Shear
`force resistance in all directions, therefore a high COF
`results under various walking Scenarios of pitch, angle and
`load.
`While the mesh layer nodes possess a high COF even in
`dry conditions, a polymer Surface coating Such as EVA
`copolymer may be applied to the mesh to increase the COF.
`An example of Such a coated mesh is Thermanet", pro
`
`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 7
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`7
`duced by Conwed PlasticsTM of Minneapolis. The mesh
`layer may be coated on both sides with EVA, which will
`reduce the incidence of delamination of the mesh layer from
`the Structural layer.
`The mesh design (nodes/unit area), mesh polymer type,
`and node shape, Size and weight may be Selected to optimize
`foot traction and coating layer Securement. If the node
`density is too high, the Surface may become effectively
`Smooth, and: may not provide slip resistance. If the node
`density is too low, the mesh may not provide Sufficient
`traction under wet characteristics.
`The Structural layer may comprise woven tapes of poly
`olefin Such as polyethylene or polypropylene, or woven
`reinforced membrane Substrates Such as polyethylene
`terephthalate, nylon or glass. Alternatively, the Structural
`layer may comprise non-woven polyolefins Such as spun
`bond polyolefin, or non-woven reinforced membrane Sub
`Strates Such as polyethylene terephthalate, nylon or glass.
`Other materials are also possible.
`The use of a nodular mesh material provides the benefits
`of hard, rigid inorganic particles under wet conditions, but is
`more compatible with polymer underlayment manufacturing
`processes than is addition of inorganic particle coatings. The
`Strands and nodes together provide a traction mechanism,
`with the strands providing reinforcement to the nodes. The
`use of nodes without strands would be undesirable as Such
`Stand alone nodes would be Vulnerable to Shearing off unless
`extremely high adhesion forces were present.
`Referring to FIG. 3, roofing underlayment 30 has a mesh
`layer 12 laminated to the upper Surface of a structural layer
`11. A high COF film 15 is laminated by a first lamination
`layer 16 to the lower Surface of the structural layer. The high
`COF film may comprise EVA. The mesh layer is laminated
`to the Structural layer by a Second lamination layer 13.
`AS wet conditions generally are not found on the deck side
`of the underlayment, it is not necessary to laminate the mesh
`layer to the bottom surface of the underlayment. Sufficient
`COF between the underlayment and the deck may be
`achieved by application of tacky coatings Such as EVA to the
`lower Surface of the underlayment. It is advantageous to
`provide a high COF between underlayment bottom and the
`deck Surface, as applicators are likely to walk over the
`underlayment before it is Secured. Any Slippage between
`underlayment and deck may cause accidents. The use of
`coatings such as EVA, increases the COF between the deck
`and the bottom of the underlayment to render the underlay
`ment Secure until the underlayment is fully Secured by
`roofing nails or Staples.
`One or more of the layers of the sheet material may be
`lightly coloured to provide reflection of Solar radiation. This
`provides the sheet material with leSS heat absorption, which
`results in a cooler roof, lower attic temperatures, and a
`cooler working Surface for applicators. The sheet material is
`lightweight for faster installation and lower Volume to
`inventory and handle.
`In one particular embodiment, the invention is a Synthetic
`roofing underlayment comprising of a woven tape Structural
`layer of polyethylene or polypropylene, extrusion coated
`with low-density polypropylene on the top Surface, and a
`thermoplastic noded mesh material coated on both Sides by
`EVA (such as Conwed. Plastics ThermanetTM 750012-018)
`Simultaneously laminated onto the top Surface of the Struc
`tural layer. The oriented Strands are typically approximately
`0.15 mm (0.006 inches) in thickness, whereas the node
`junctions are approximately 0.5 mm (0.02 inches) in
`thickness, thus providing a nodular characteristic for
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`US 6,925,766 B2
`
`8
`enhanced shear load bearing. The bottom Surface of the
`underlayment is coated with EVA by direct extrusion, or
`lamination of an EVA film by thermal bonding or coating.
`EVA grades are preferably 5-20% EVA comonomer, such as
`Dupont ElvaxTM or similar resins imparting a static or
`dynamic COF near 1.0. The woven structural layer provides
`high Strength and light weight for ease of application, and
`resistance to tearing and wind blow off. The underlayment is
`free of buckling and wrinkling characteristic common in
`organic asphalt felts.
`The Structural layer, lamination layer, coatings, and mesh
`layer may be treated with UV stabilizers to provide for
`exposure resistance during applications where the underlay
`ment has been installed to dry-in the roof, but application of
`the primary roofing material is delayed. This Scenario is very
`common in tile and metal roofing applications. One or more
`layers may be treated with a mold inhibitor or fire retardant
`additive.
`The noded Surface of the present invention enables its use
`in a variety of applications where Safe walkability in
`extreme conditions or on pitched Surfaces is required.
`Further, the inner Surface of this product can be treated
`with adhesives backed by a release liner that protects the
`adhesive and prevents the product from Sticking to itself.
`During application, the release liner is easily removed to aid
`in positioning of sheets and to maintain properline, allowing
`the product to Stick to the installation Surface and eliminat
`ing the need for mechanical fasteners which puncture the
`underlayment, thereby generating opportunities for water
`penetration.
`Referring to FIG. 4, in roofing underlayment 40, a mesh
`layer 12 is laminated by a synthetic lamination layer 13 to
`the top surface of the structural layer 11. The bottom surface
`of the structural layer 11 is coated with a thin adhesive layer
`17 which is laminated to a removable release liner 18.
`An alternative embodiment provides a mesh layer lami
`nated to molten rubberized asphalt to produce a Self
`adhering underlayment exhibiting good walkability under
`wet conditions. Typically, a polymer such as KratonTM (Shell
`Chemicals) rubber is emulsified within an asphalt matrix to
`produce a highly elastic core Sealing membrane layer which
`is laminated to an outer film Surface, and the bottom Surface
`is coated with an adhesive to which is laminated, to a release
`liner.
`Referring to FIG. 5, in underlayment 50 a mesh layer 12
`is laminated to the upper Surface of a bituminous rubberized
`asphalt layer 19 1.6 to 2.4 mm (0.040 to 0.060 inches) thick.
`The lower surface of the asphalt layer is coated with a thin
`layer of adhesive 20, which is laminated to a removable
`release liner 21. Underlayments having an adhesive layer
`and release paper are commonly known as "peel and Stick'
`underlayments.
`The roofing underlayment of the present invention has
`high tensile and tear Strengths, exhibits a high COF in dry,
`wet or dusty conditions, and is lightweight, permitting fast
`installation and reducing the number of rolls of underlay
`ment to inventory and handle.
`The Synthetic polymer construction of the present inven
`tion is free from wrinkling and buckling caused by water
`absorption. Such water effects are common with asphalt
`felts, and can interfere with primary roof covering installa
`tion.
`The sheet material of the present invention has been
`evaluated as a roofing underlayment and passed by an
`external lab in accordance with International Conference of
`Building Officials Evaluation Services (“ICBO-ES”) Accep
`
`Louisiana-Pacific Corporation, Exhibit 1058
`IPR of U.S. Pat. No. 8,474,197
`Page 8
`
`

`

`US 6,925,766 B2
`
`10
`
`TABLE 3
`
`9
`tance Criteria for AC 188 & AC 48 (incl