Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including a foamed layer or component
Reexamination Certificate
1999-08-18
2002-04-02
Copenheaver, Blaine (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Including a foamed layer or component
C442S373000, C442S076000, C442S077000, C442S136000, C156S077000
Reexamination Certificate
active
06365533
ABSTRACT:
BACKGROUND OF THE INVENTION
Rigid polymeric foam insulation laminates have been used for many years by the construction industry. Uses include commercial roof insulation boards utilized under asphaltic built-up roof (BUR) membranes as well as under various single ply membranes such as EPDM rubber, PVC, modified bitumen membranes and the like. Other uses include residential insulation, as sheathing under siding, and as roof insulation under asphalt shingles and concrete tiles.
Such insulation often takes the form of a core polymeric foamed thermoset material such as polyurethane, polyisocyanurate, polyurethane modified polyisocyanurate (often referred to as polyiso) or phenolic resin, applied between two facing sheets.
These insulation boards are generally manufactured on production lines where a liquid core chemical mixture is poured over a bottom facer, foaming up to contact a top facer in a constrained rise laminator. The reaction of the chemical mixture causing foaming is generally exothermic, as curing via polymerization and crosslinking occurs in the laminator. In the case of polyisocyanurate insulation boards, the curing exotherm lasts well into the time the resulting rigid boards are cut, stacked and warehoused. The exotherm can continue for as long as 4 days and the mixture can reach temperatures as high as 325° F.
Desirable properties for the facers include flexibility, high tensile and tear strength and resistance to thermal degradation. Facer porosity should be low and the thickness of the facer coating should be sufficient to prevent bleed-through of the liquid chemicals prior to foaming. Additionally, facers should exhibit good adhesion to the core foam insulation and be inert to the effects of extraneous chemicals which may be present in the mixture, especially blowing agents that also behave as solvents. Blowing agents currently in use include chlorofluorocarbons like HCFC-141b and R-22 as well as hydrocarbons such as n-pentane, cyclo-pentane and iso-pentane.
One problem that has plagued the polyiso industry has been a phenomenon called “cold temperature delamination”. This phenomenon occurs in cold temperature areas where insulation boards coming off the production line cool before they can be “stack cured”. In a worst case scenario, the polyiso core foam layer closest to the facer cools, quenching the cure reaction and leaving a brittle layer. This often leads to shearing of the core layer or facer peel off. It has been the practice of manufacturers to place a layer of corrugated cardboard over both the top facer surface of the top board and under the bottom facer surface of the bottom board in the stack, to retain exothermic heat and prevent subsequent delamination. Thus, a facer that inherently insulates and retains heat during stack cure would materially reduce incidents of cold temperature delamination and would eliminate the need for costly cardboard insulation.
After these foamed polymer insulation boards are cured, cut and shipped to their use site, the facer should provide mechanical stability as well as water and weather resistance since, upon installation, they may be exposed to persistent rain, high humidity, ultraviolet light and excessive heat. Additionally, the facers must be puncture and scuff resistant to survive being nailed and walked on. Withstanding temperatures up to 500° F., as encountered in hot asphalt applications, as well as resistance to the deleterious effects of adhesive solvents used in single ply roofing membrane applications while strongly bonding to the adhesives themselves are also important facer properties.
Traditionally, facer materials have included asphalt saturated cellulosic felts, fiberglass mats, asphalt emulsion coated fiberglass mats, aluminum foil/Kraft/foil, glass fiber modified cellulosic felts, glass mats onto which polymeric films have been extruded, and glass mats coated with polymeric latex/inorganic binder coatings. However, all of these materials have at least one undesirable property. For example, asphalt-containing products are not compatible with PVC single ply roofing membranes. Fiberglass mats are subject to excessive bleed-through of foamable core chemicals. Aluminum facers and foils reflect heat into the foam during processing which leads to disruption of cell structure, delamination and warping. Further, foil faced sheathing and extrusion or lamination of a polymer film to glass mat surfaces are costly. Specifically, glass mats coated with polymer latex/inorganic binder mixtures have been found to be brittle; conversely, glass fiber modified cellulosic felts are susceptible to moisture absorption aggravating board warping in damp or wet environments.
Other facers which have been employed for siding underlayment and insulation board facers include those disclosed in U.S. Pat. Nos. 5,776,841 and 5,717,012, which are primarily felts.
U.S. Pat. No. 5,001,005 describes a facing sheet composed of glass fibers and a non-asphaltic binder. The facer contains 60-90% glass fibers, which high fiber content does not provide sufficient binder to close the sheet's pores or to provide desired sheet strength. U.S. Pat. No. 5,102,728, describing a glass mat substrate coated with a polymeric latex blended with an asphalt emulsion, concerns a product which is not only incompatible with PVC roofing membranes but also requires excessive coating thicknesses to reduce high porosity. Accordingly, this product is very costly. U.S. Pat. No. 5,112,678 discloses a facer prepared by applying to a fiberglass mat a flowable polymer latex and an inorganic binder coating. The resulting product is somewhat brittle and is susceptible to an undesirable degree of chemical bleed through. U.S. Pat. Nos. 5,698,302 and 5,698,304 describe facers where polymer films are laminated or extruded onto fiberglass mat. Not only is this approach costly, but also since conventional mineral flame retardant filled polymers do not extrude well, some degree of resistance to flammability must be sacrificed.
Accordingly it is an object of this invention to overcome the above disadvantages and deficiencies and to provide a facer which is economically produced by a commercially feasible process.
It is also an object to provide a mechanically stable facer suitable for insulation board manufacture which resists cold temperature delamination and which has superior tolerance to the effects of weathering.
Another object is to provide a facer which exhibits superior adhesion to polyiso foam of an insulation board core material.
These and other objects and advantages of the invention will become apparent from the following description and disclosure.
SUMMARY OF THE INVENTION
The non-asphaltic, non-cellulosic facer of the present invention comprises a dry, preformed fibrous mat substrate on which is coated a pre-frothed or pre-foamed composition containing a natural or synthetic thixotropic latex polymer, a surfactant and an inorganic mineral filler. The composition may optionally contain up to about 15 wt. % of extraneous additives, which include a flame retardant, dye, thickener, porosity reducing agent, thermal and/or UV stabilizers and the like, to provide a foamed facer product having, on a dry weight basis, less than 50% fiber in the mat. The preferred facer product contains 30 to 46 wt. % of fiber in the composition consisting of mat fiber with binder and latex in the coating mixture.
DETAILED DESCRIPTION OF THE INVENTION
Generally, the foamed coating composition applied to the preformed mat contains on a dry weight basis between about 15 and about 80 wt. % of the thixotropic polymer latex, between 0.01 and about 80 wt. % filler, between about 0.5 and about 10 wt. % foam supporting surfactant and 0 to 15 wt. % extraneous additives.
The fibers of the mat employed in this invention include any of the non-cellulosic types, such as fibers of glass, polyester, polypropylene, polyester/polyethylene/teraphthalate copolymers, hybrid types such as polyethylene/glass fibers and other conventional non-cellulosic fibers. Mats having glass fibers in random orientatio
Franzyshen Frank S.
Horner, Jr. Charles J.
Sherman Murray S.
Building Materials Investment Corportion
Copenheaver Blaine
Davis William J.
Katz Walter
Maue Marilyn J.
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