TECHNICAL FIELD

The present invention relates to improved insulation board performance imparted by enhanced physical properties through the use of woven mats as facers for insulation boards used in building construction in general and in roofing construction in particular. When used in a roof assembly, the present invention permits the roofing system to meet the Very Severe Hail (VSH) testing rating with a low or typical density insulation board.

BACKGROUND OF THE INVENTION

Currently, facers for polyurethane or polyisocyanurate (Polyiso) foam roofing insulation boards are typically made either from a Glass Reinforced Paper (GRF) facer or from a Coated Glass Facer (CGF) material. Facers serve a few purposes on the insulation board and in the roof system. For example, facers help provide structural integrity to the foam board and protect the friable foam surface from forces exerted by hail, foot traffic, heavy HVAC equipment and construction equipment. Facers also provide added strength to the foam board with regard to wind uplift performance. Both GRF and CGF contain fiberglass and thus are skin irritants during the manufacturing process and in end-use application. With GRF facers, glass fibers are added to the paper to improve dimensional stability, especially when the facer is wet. However, the glass fibers do not prevent the board from warping due to dimensional change in the GRF facer after exposure to moisture, or from losing strength while exposed to moisture, such as a leak. While coated glass facers do offer improved resistance to moisture and mold when compared to GRF facers, these facers discolor after exposure to moisture, and are rigid so they do not spread force across the board, and also have the tendency to absorb excessive amounts of chemicals during the production of the foam board. Additional disadvantages of these fiberglass containing facer materials include: (a) they do not offer sufficiently strong indentation resistance, (b) they tend to peel off and delaminate from the polyurethane or polyisocyanurate insulation boards, and (c) the glass fiber content results in handling complaints during production and installation of the boards.

Importantly, the fasteners that secure these foam roofing boards to the roof also pass through the boards' facers. Unfortunately, wind uplift across the boards can cause fastener pull-through which results in failure of the fully adhered roof system. To improve wind uplift performance of the roof system, additional fasteners are typically driven through the insulation board to keep the board anchored to the roof deck.

Therefore, what is instead desired is a polyurethane or polyisocyanurate foam roofing insulation board facer material that would both provide load spreading and added surface strength. Specifically, it would be desirable to provide a facer that assists in spreading surface loads such that the potential for fastener pull-through during wind uplift can be reduced or eliminated. The advantage of load spreading to prevent fastener pull-through also helps to firmly secure the foam insulation board to the roof. Another advantage of such added surface strength is that it would offer increased indentation resistance. This indentation resistance would be advantageous against hail hitting the roof. Most preferably, the ideal roofing system would be able to pass the recently announced “Very Severe Hail” test rating announced by Factory Mutual as described in FM 4470 (Class 1—VSH). In addition, a facer having the desired indentation resistance would also be advantageous against workers kneeling on the roof or foot traffic on the roof during installation or roof repair. As will be explained, the present system provides this strength and load-spreading advantages. In fact, the present system has been shown to meet the Very Severe Hail (VSH) test rating. In addition, the present facer even preferably permits the roofing system to meet the Very Severe Hail (VSH) test rating even when a low or typical density insulation board is used (For example, such a density range can even be as low as found in typical density insulation boards, and could even be in the range of 0.5 to 6.0 pcf).

While load spreading will allow higher wind uplift values to be achieved with equivalent fasteners, load spreading will also allow an equivalent uplift to be achieved utilizing fewer fasteners. Reducing the number of fasteners in a roof system while maintaining wind uplift performance is highly advantageous because it requires less labor to install a roof system with fewer fasteners, fewer fasteners reduces the material cost of the roof system, and fewer fasteners results in fewer penetrations of the polyurethane or polyisocyanurate foam board, minimizing heat sinks, thereby leading to improved insulating performance of the insulation board.

SUMMARY OF THE INVENTION

In one aspect, the present invention comprises an insulation board assembly, having: a foam insulation board (which may optionally be polyurethane or polyisocyanurate, or a phenolic material or an expanded polystyrene material (EPS)); a woven mat as the top facer attached onto a top side of the foam insulation board; and a woven mat as the bottom facer attached onto a bottom side of the foam insulation board. Optionally, the woven facers may be made of natural and/or synthetic yarns and/or tapes. Suitable synthetic yarns or tapes can be made from polymers such as polyethylene, ethylene and alpha-olefin copolymers, polypropylene, propylene and alpha-olefin copolymers, nylon, polyester, acrylic polyester, polyamide, aramid etc. Suitable natural yarns can be made from nature fibers, such as cotton, cellulose, wool, rayon, silk, hemp, sisal, etc.

The present invention also comprises a roof assembly, comprising: a roof deck; an insulation board assembly mounted onto the roof deck; and a roofing membrane adhered onto the insulation board assembly, wherein the insulation board assembly comprises: a foam insulation board, a woven top facer on a top side of the foam insulation board, and a woven bottom facer on a bottom side of the foam insulation board.

The woven mats can have different weave density. Fabric Mesh is a measure of the density of the fabric weave as the number of yarns or tapes per inch in both the Warp (machine) and Weft (cross) directions. Ends per inch (EPI) is the number of warp yarns or tapes per inch of woven fabric and picks per inch (PPI) is the number of weft yarns and tapes per inch of woven fabric. For example, the weave density can be 2 tapes per inch×2 tapes per inch (EPI×PPI) to 100 tapes per inch×100 tapes per inch. Preferably, the weave density would be 4×4 to 60×60 mesh. Most preferably, the weave density would be 4×4 to 30×30 mesh. Optionally, the woven mats have different weave density along warp and weft direction, for example, the weave density can optionally be 4×8 mesh in one embodiment.

The present woven mats can have different weights, typically measured by the fabric weight in ounces per square yard or grams per square meters. For example, the woven mat weight can optionally be from 10 gsm to 400 gsm. Preferably, the woven mat weight could be from 20 gsm to 200 gsm. Most preferably, the woven mat weight could be from 40 gsm to 100 gsm. Alternatively, the woven mats can have different thicknesses. For example, the woven mat thickness can be from 1 mil to 200 mil. Preferably, the woven mat thickness could be from 2 mil to 100 mil. Most preferably, the woven mat thickness could be from 2 mil to 50 mil.

Optionally, the woven mat can have a coating on one or both sides of the surface. The coating can be of different polymer compositions, such as polyethylene, ethylene and alpha-olefin copolymers, polypropylene, propylene and alpha-olefin copolymers, silicones, acrylates, natural rubber, styrene-butadiene rubber, etc. Advantageously, such coating will provide bleed through resistance during the polyurethane or polyisocyanurate board manufacturing process, water resistance during foam board transportation, and slip and water resistance during field installation. The coating may additionally provide improved adhesion to the polyurethane or polyisocyanurate foam during manufacturing and provide improved compatibility and adhesion to bonding adhesives during field installation. The bonding adhesives can consist of different polymer compositions, such as polyurethane, nitrile, neoprene, chloroprene, silane-terminated polyether, styrene butadiene rubber, acrylic, ethylene propylene diene monomer (EPDM), etc.

Optionally, each of the top and bottom woven mats can have an additional layer of non-woven material laminated to one or both sides. The lamination could optionally be done with adhesives or with a tie layer. When the non-woven layer is in contact with the polyurethane or polyisocyanurate insulating foam during the manufacturing process, the non-woven layer may increase the surface roughness and surface area of the woven mat to allow the woven mat to have better adhesion or bonding with the polyurethane or polyisocyanurate foam. When the non-woven layer is positioned on the outside (i.e.: top or bottom) of the foam insulation board, it may enhance the slip resistance and improve adhesion performance with bonding adhesives during the field installation. The non-woven fiber can optionally be made of different polymer composition, such as polyester, polyethylene, ethylene and alpha-olefin copolymers, polypropylene, propylene and alpha-olefin copolymers, nylon, glass, Kevlar, basalt, carbon fiber, etc.

Optionally, the woven mats may be laminated with a glass scrim, glass mat, carbon fibers scrim, or coated PET scrim. When laminated to the woven mat, these materials could potentially improve dimensional stability of the facer and the insulation board.

Optionally, the woven mats can be made of low shrinkage polymer yarns or tapes. The shrinkage rate of polymer tape can be assessed by the percentage of length change when the polymer tape is heated from room temperature to 100° C. Preferably, the polymer tape used in the woven mat has <10% in shrinkage rate. Most preferable, the polymer tape has <5% shrinkage rate.

Optionally, flame retardants can be added to polymer yarns or tapes to enhance the fire resistance of the woven facer.

In another aspect, the present invention comprises a rolled woven facer material having a sufficiently desirable strength in both its machine direction and its cross direction. This rolled woven material can then be used as a top and/or bottom facer to a polyurethane or polyisocyanurate foam insulation board. Preferably, this rolled woven facer material is quite thin and has low weight.

In preferred embodiments, the present woven polypropylene facer has a tensile strength greater than 80 lbf/3 inch in both a machine direction and a cross direction, and also has a tongue tear strength of over 15 lbf in both a machine direction and a cross direction.

Advantages of the present woven facer material include the fact that it provides added surface strength, load-spreading and durability as compared to existing GRF and CGF facers. Such added surface strength and load-spreading allows for foot traffic and kneeling on the insulation boards during roof installation. It also provides superior hail resistance and equivalent mold/moisture resistance to that of CGF. Specifically, the present roofing system comprising the present facer has been shown to meet the “Very Severe Hail” test rating announced by Factory Mutual as described in FM 4470 (Class 1—VSH).

The present woven facer is preferably a light but strong and heavy duty material. An advantage of the present woven facer material is that it has higher fastener pull through force, and thus provides excellent wind uplift resistance after the insulation board has been secured to the roof. In addition, the present woven facer system is also very durable and lengthens the effective lifespan of the foam roofing insulation board. In optional embodiments, the woven facers are made of a polymer, such as polyethylene, ethylene and alpha-olefin copolymers, polypropylene, propylene and alpha-olefin copolymers, nylon, polyester, polyamide, etc. However, it is to be understood that other woven materials including both natural and synthetic yarns or tapes, such as cotton, cellulose, rayon, silk, hemp, sisal, etc. can be used as well.

As such, the present woven facer system also offers the advantages of a higher flex modulus and a higher fastener-plate pull-through resistance as compared to traditional GRF and CGF facers.

In the case of a woven polypropylene material, the present facer can optionally be made from a plastic film that has been drawn into filaments or tapes, and then woven to create a fabric sheet or mat. In these preferred aspects, the woven mat optionally comprises a nonwoven layer on one side that will promote adhesion to the polyurethane or polyisocyanurate foam and polymer coating on the other side that will enhance water, moisture and bleed through resistance. The polymer coating can optionally provide improved compatibility and adhesion to bonding adhesives during field installation.

Another advantage of the present woven facer material is its low cost. In addition, the present woven facer materials can optionally be made from recycled plastics, providing environmental benefits.

