MXPA97006590A - Roofing members who have improved dimensional stability and related methods - Google Patents

Abstract

A method for relocating a roof comprising applying laminated recovery boards of the present invention to a roof platform, and applying a protective layer outdoors on the recovery boards. Laminated recovery boards comprise foam core (11) selected from the group consisting of polyisocyanurate and polyurethane materials and mixtures thereof, and first and second coatings (12, 13) between which the foam core is walled, the coatings comprise a polymer sheet containing a reinforcing material selected from the group consisting of glass strands, glass fibers and mixtures thereof, wherein the polymer sheet is selected from the group consisting of polypropylene and polymer latexes, and a protective layer is applied outdoors on laminated recovery boards

Description

ROOFING MEMBERS WHO HAVE IMPROVED ECTAPI IPAO PPffiWSIQNAL AND METQPQS RELACIQ PQS ECHNICAL FIELD This invention relates to a laminated board suitable for use as a recovery board within a roof system. Particularly, the present invention relates to a laminated board having improved dimensional stability, especially when exposed to extreme environmental conditions including high heat, humidity and hygroscopicity. BACKGROUND OF THE INVENTION The construction of ceilings in a low inclination roof, generally consists of a roof platform, an insulating barrier on the platform, an environmental resistance layer applied to the insulating layer and optionally a layer of material such as ter oresistant The roof platform generally includes materials such as wood, plaster, concrete, steel and the like. On the roof deck, insulation boards or insulators are typically applied to provide thermal insulation and a uniform surface to which the protective layer of the environment is applied. The most common recovery boards are made of wood fibers or extruded polystyrene. The recovery boards can also be made with a variety of core materials that typically are coated with a front or protective coating that can be rigid or flexible and optionally fire retardant or flame retardant. In a re-roofing operation, the roof deck can refer to the existing roof, including the existing insulation and the weather-resistant layer. Recovery boards, as they refer to roofing again, have been used when the existing roof leaks or leaks. These boards generally apply to an existing roof platform structure to provide a uniform surface when an existing roof is recovered. The most common recovery boards are made of wood fibers or extruded polystyrene. Wood fibers are typically coated with a thin layer of asphalt material on the one hand, and recovery boards that are made of polystyrene typically do not contain a coating. To seal the roof of the elements, the recovery boards are typically covered with various materials including molten asphalt, modified bituminous membrane, rubberized asphalt, or an elastomeric composition, such as EPDM (ethylene-propylene diene monomer). Not all sealing materials, however, are compatible with each type of recovery board. For example, molten asphalt can not be used with extruded polystyrene. Correct combinations of seal material and recovery board are known to those with skill in the industry.

The thermally resistant layer of material, which is generally applied directly to the weather-resistant layer, may include gravel, river stones, foam or a layer of mastic followed by granules. The application of the protective layer outdoors can be achieved by a number of means, usually dictated by the type of material used. For example, sheets of a protective membrane can be unrolled on the roof and joined together by torch or the use of an adhesive. Although economical and generally widely used, recovery or insulation boards containing wood and polystyrene fibers are often ineffective in hot, humid and hygroscopic environments. Particularly, agglomerated boards of wood fibers will disintegrate in a humid, hygroscopic environment, which is common in a roofing operation again. Polystyrene will expand, warp or distort in similar environments, especially when exposed to extreme heat on roofs in hotter climates. The patent literature includes panels and boards used for roofing operations. Constructed roof constructions and their components, for example, are well known in the art, as is generally explained by Blanpied in U.S. Pat. No. 5,001,005, Dybsky et al., U.S. Pat. No. 4,944,818 and Rosato et al., Patent of the U.S.A. No. 4,388,366. With regard to insulation boards, Blanpied illustrates a rigid foam board comprising a thermoset plastic foam sandwiched between two coatings; the coating comprises glass fibers, non-glass filler and a non-asphalt binder. Similarly, Dybsky et al. Illustrate a substrate panel for composite roof comprising a core of combustible material such as fibers or foams and a coating of non-combustible material such as glass fibers coated with a bituminous material. Rosato et al. Illustrate a laminated insulating board comprising a core of plastic foam and at least one facing sheet which forms both a protective layer and a venting medium for fluids; the cover sheet comprises the fine glass fibers bonded together with a polyvinyl acetate. In this way, there is still a need for a recovery board that can be exposed to humidity during installation and remain dimensionally stable while wet and during eventual evaporation of moisture. The use of a urethane foam and / or isocyanurate-containing composite between coatings comprising a polymer such as polypropylene, polymer latices and the like, reinforced with glass strands or glass fibers and optionally a filler, such as calcium carbonate , clay, mica and the like, makes the compound of the present invention dimensionally stable and relatively insensitive to moisture for roofing again.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a relatively inexpensive laminated board, particularly for use in roofing again, which is dimensionally stable in hot, humid and hygroscopic conditions. Another object of the present invention is to provide a laminated board having a coating that can withstand the application of adhesive of the protective layer to the weather on the roof. Another object of the present invention is to provide a laminated board that has sufficient integrity to patch or cover the roof. Another object of the present invention is to provide a laminated board which provides a good base for subsequent application of the final layer or roof covering and which is compatible with the latter and the respective means of application. Still another object of the present invention is to provide a method for roofing again using a laminated board. Still another objective is to provide a method for manufacturing laminated boards of the present invention. At least one or more of the above objects of the present invention in conjunction with their advantages over existing asphalt materials that will be apparent from the specification that follows, are achieved by the invention as described and claimed below. In general, the present invention provides a method for re-roofing which comprises applying laminated recovery boards to a roof platform, the recovery boards comprising a foam core selected from the group consisting of polyisocyanurate and polyurethane materials and mixtures thereof.; and first and second coatings between which the foam core is walled. The coatings comprise a polymer sheet containing a reinforcing material selected from the group consisting of glass strands, glass fibers and mixtures thereof, wherein the polymer sheet is selected from the group consisting of polypropylene latices and polymer; and apply a protective layer to the weather on the laminated recovery boards. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a roofing member according to the present invention; and Figure 2 is a schematic view of the apparatus used to manufacture roof members of the present invention. PREFERRED MODALITY FOR CARRYING OUT THE INVENTION The present invention is directed to a laminated board or roofing member that is used to re-roof an existing roof. The roofing member is applied to a roof platform that is substantially flat or of low inclination and that can be newly constructed or that is exposed by the removal of the old roof or that is an existing roof system in a condition suitable for recovery. Since the roof platforms are known and do not constitute part of the present invention, apart from a substrate or base on which the roofing members are placed, no further details are necessary. Although roofing members can be used as part of new roof installations, boards are designed specifically for roofing operations again. A common problem in the majority but in all the installations to put ceiling again is a roof or substrate humid and often somewhat deteriorated. Typically, when a leak or runoff is noted, and surely when it is considered necessary to repair, the use of the laminated board of the present invention provides an economical and easy means of roofing again, either in the affected area or more commonly all ceiling. In this way, the roofing member must have sufficient integrity to patch or cover the roof; it must provide a good basis for subsequent application of the final layer or cover, such as EPDM roofing membrane; and must be compatible with the latter and the respective means of application.

In other words, a board placed on the old roof to act as a substrate for the new waterproof membrane will typically become wet. Existing boards made from wood fibers, extruded polystyrene will distort and / or deteriorate, requiring greater efforts to put roof back on. Existing boards manufactured from isocyanurate foams will work better, except that the existing state of the art has been to use coatings that also absorb water, causing untimely failure of the board in certain situations where moisture is found. Existing coatings contain organic felt, which provide an action of capillarity absorption through the coating. While these problems can be minimized by drying the roof before repair, or by waiting for it to dry, this is often not practical. Other coating materials have employed glass reinforcing components and glass fibers with urea / formaldehyde resin as a binder; however, these "all glass" coatings, as they are sometimes referred to, are notorious for a condition known as "penetration of the leaf causing a spot on the opposite side" (strike through) during the manufacturing process. When this happens, the foam can penetrate more easily through the coating and reach the lamination equipment causing it to freeze as well as creating other manufacturing problems. This weakness has been attributed somewhat to the use in the polymer industry as binding agents that are porous to allow venting of gases and vapors. Polyvinyl acetate, for example, is often used as the binding agent to provide said porosity in glass reinforced coatings. The laminated board according to the present invention is better described with reference to Figure 1. This board is generally indicated by the numeral 10 and comprises a foam core 11 sandwiched between a lower covering 12 and an upper covering 13. The boards 10 in general they are from about 1.27 to about 10.16 cm (about .5 to 4 inches) thick, and more preferably from about 1.27 to about 3.81 cm (about .5 to about 1.5 inches) thick and preferably about 1.27 to about. approximately 2.54 cm (.5 to 1 inch) thick and can be manufactured in various dimensions depending on the intended application. Boards manufactured in sheets of 1.22 meters (4 feet wide) and 2.44 meters (8 feet) long, are best suited for compatibility in the construction industry. The foam core 11 may be polyisocyanurate or mixtures thereof. The foam core in general is of standard production and generally includes those that have an approximate index of 250. Particularly, when polyisocyanurate foam is used, those that have an index over 200 are preferred; and when urethane is employed, an index above 120 is preferred. In addition, mixed foams may be employed, such as a mixture of polyisocyanurate and urethane. The lower coating 12 and upper coating 13 are generally of the same or similar compositions, but embodiments within this invention may include a top and bottom coating comprising different compositions suitable for a particular use. The top and bottom coatings of the present invention comprise reinforced polymer material, thereby forming a polymer sheet. In particular, the polymer material may include polypropylene, polymer latices or mixtures thereof. Examples of the latter include styrene-butadiene rubber (SBR), polyvinyl chloride, polyvinyl alcohol and mixtures thereof. Thicknesses of the coatings are typically in the range between approximately .0254 and .381 cm (.01 and .15"). The polymer material also includes reinforcing materials such as glass strands., glass fibers or their mixtures. Amounts of these reinforcing materials are in the range of about 100 to about 10,000 parts by weight based on 100 parts by weight of the selected polymer to form the coating. In addition, the reinforced polymer material may optionally include fillers such as clay, mica, talc, lime, calcium carbonate, gypsum (calcium sulfate) aluminum trihydrate, antimony oxide, cellulose fibers, plastic polymer fibers and mixtures thereof . Amounts of these fillers are in the range from about 0 to 5000 parts by weight based on 100 parts by weight of the selected polymer to form the coating. The coatings of the present invention have been found to impart weather resistance and durability to laminated boards used as roof substrates within a constructed ceiling. Particularly the coatings of the present invention have been found to provide dimensional stability to the boards, inhibiting the boards against distortion under high heat and humidity. In addition to dimensional stability, the coatings protect the foam against moisture as well as against penetration. Because of these advantages, the coatings of the present invention have been found particularly useful with recovery boards because the environment commonly encountered in a roofing operation again is hot humid and often hygroscopic. Furthermore, the optional fillings contribute to the coating resistance and provide the coating with a robust appearance. The laminated boards 10 typically are applied to the roof platform in adjacent parallel and stepped sections that border each other. The boards are generally fastened to the platform by nails or adhesive, although other means for attaching an insulating board to the roof platform are common in the specialty. Once the recovery or lamination board of the present invention has been applied to a roof platform, the roof is completed by covering the substrate with a weather protection layer. The protective layer can include any system where the temperature application will not melt the polymer or latex. Accordingly, the means for connecting the roof covering with the recovery board will not exceed 100 ° C, which essentially discharges the molten asphalt. Useful systems typically include various types of EPDM or modified bitumen roofing membranes or any other suitable protective layers known in the art. In ballasted roofs, this protective layer is then covered with gravel, river stones or their mixtures; where the weight of the river stones serves for a second function, which is to hold the protective layer and the underlying materials, such as the recovery boards to the roof platform. While the boards can be manufactured in a batch process, a continuous online process is preferred since said process is both efficient and economical. With reference to Figure 2, a continuous process is illustrated schematically in conjunction with the apparatus 20. The apparatus provides upper and lower spools 21 and 22 respectively for upper and lower coatings 12 and 13 which are placed to feed a rolling structure, generally 24, comprising lower and upper continuous belts or belts 25 and 26 connected around a series of rollers 28, several of which are directed. The bottom or bottom cover 12 is first fed to the laminator 24 which rests on the strip 26. Immediately on the cover 12, as it enters the laminator 24 is a foam mixing head 30. The mixing head 30 is fed from the tanks 31 and 32 or any amount that is required by the selected polymer foam composition. Typically there are two mixing heads per laminator. When the desired foam is a polyurethane, for example, the reservoir 31 can provide the isocyanate components and the reservoir 32 the polyol components. The resin materials of these deposits are fed through metering pumps 33 and 34 and through appropriate conduits 35 into the mixing head 30 where upon contacting, the reaction begins to form the polymer foam. The mixing head 30 then supplies an appropriate mixture 36 of resins from reservoirs 31 and 32 as well as an amount dosed appropriately on the surface of the moving coating 12. Subsequently, downwardly of the mixing head 30, the top coating 13 it feeds the laminator 24 passing around a feed roll 38 which places the cover 13 against the upper band 26. As the coatings and deposited foamable composition are transported, the latter rises, as illustrated at 40, until the topcoat 13 It is in full contact with the upper band 26. It will be appreciated that the bands 25 and 26 are adjustable to allow the desired thicknesses of the board 10. After the foaming has completed the intermediate product, indicated by the number 42 is heated to effect curing of the polymer. This is achieved by properly located heaters, generally 44 or by passage through an oven (not shown). After heating for the appropriate time (residence) and temperature, the product emerges from mills and is cut into sections to produce the boards 10. This cut is within the skill of the specialty, including aerial cutting saws and the like, which provide the desired dimensions without interruption of the apparatus 20. While sections may be varied at will of said apparatus, the widths of the boards 10 may be subsequently cut to size in a separate operation as necessary. It is also possible to provide side walls (not shown) in conjunction with the laminator 24, to define the desired widths as the polymer foams within the laminator. EXAMPLES In order to demonstrate the practice of the present invention, four types of construction boards were selected. A board includes wood fibers such as that sold by Georgia Pacific under the trade name Sturdy Top, which has an EPDM coating of 1.14 mm (45 mil) on one side. A second board includes extruded polystyrene such as that sold by the Dow Chemical Company under the trade name Recover Mate. The third board manufactured in accordance with the present invention includes a polyisocyanurate foam core having identical top and bottom coatings, comprises polypropylene reinforced with glass fibers, the glass fibers comprise approximately 85% by weight of the coating. The fourth board is that sold by Atlas Roofing Corp., and is considered to be that described in US Pat. No. 5,001,005 in includes a core of polyisocyanurate foam having top and bottom coatings, comprising polymer latex reinforced with glass fiber and non-glass fillings. Each board had a thickness of 1.27 cm (.5 inch). Each type of board then underwent various tests. The first test was a water absorption test similar to that described in ASTM C-209. Consistent with this test, each board was exposed to water for 120 hours and the gain in percent by weight is determined and reported as described in Table I.

TABLE I GAIN IN PERCENT IN WEIGHT Ex. NO. Weight Gain Board% 1 Wood fibers (EPDM coating) 116 2 Polystyrene (Without coating) 0 (approx.) 3 Polyisocyanurate 33 (reinforced polypropylene) 4 Polyisocyanurate 30 (reinforced polymer latex) Each of the boards described above was also tested for flexural strength in accordance with ASTM C-203, Method I, Procedure A. Mentions based on the direction of The machine (MD) and machine direction (CMD) were taken when each board was dry and after 24 h of water exposure by the previous test according to ASTM C-209. The results of the test are shown in Table II. The values are given in terms of kg / cm2 (pounds per square inch). TABLE II FLEXURAL RESISTANCE Ei. No. DRY RESISTANCE FLEXURAL DRY DRY HUMID MOIST Wood Fibers 201 1.80 1.03 .93 (EPDM coating) (28.6) (25.6) (14.7) (13.2) Polystyrene 1.24 .77 .94 .64 (Uncoated) (17.7) (11.0) (13.4) (9.1) TABLE II (Cont.) FLEXURAL RESISTANCE Ei. No. DRY RESISTANCE FLEXURAL DRY DRY HUMID MOIST 3 Polyisocyanurate 1.48 1.07 1.06 1.06 (reinforced polypropylene) (21.0) (15.2) (15.1) (15.1) 4 Polyisocyanurate 1.69 1.36 1.45 1.10 (reinforced polymer latex) (24.0) (19.3) (20.6) (15.6) Boards as described above, were also subjected to a test of detachment with wind. The tests of detachment with wind were made using a table of detachment with standard wind of 1.52 x 2.74 m (5 x 9 feet). The fboards under test include a 1.27 cm (.5 inch) thick fibreboard having a protective coating of 1.14 mm (45 mils) EPDM, an extruded polystyrene board with a thickness of 1.27 cm (.5 cm). inch) that has a coating reinforced with glass fibers, and a polymer latex board with a thickness of 1.27 cm (.5 inch). Each board is mechanically clamped to the wind release board that employs a clamp and a .61 x .61 m (2 x 2 feet) clamp plate that has a diamond-in-square clamping pattern. Finally, boards as described above were tested at an outdoor test site in Mia i, Florida, at least for fmonths, between mid-February and mid-July. The boards were placed on a steel roofing platform / wood fibers, and mechanically fastened in a stepped parallel pattern so that adjacent edges confined to each other. A protective layer of EPDM is placed on the boards. Water was liberally applied to the roof deck and recovery boards before applying the EPDM layer to simulate a wet roof recovery situation. Miami conditions during this period were consistent with conditions that are normally experienced during that time of year, which is generally very humid, hot and hygroscopic. Photographs of the boards were taken before and after the trial period and observations were recorded. The observations of the tests are presented in Table IV. In general, wood fiber became moist, soft and hygroscopic, with loss of strength in all directions; Strong accumulation of ildiú and fungi was also observed. The extruded polystyrene does not become wet, but experiences expansion that leads to buckling of the board, which typically leads to deposit formation on the EPDM layer. In previous experiments, polystyrene boards experienced post expansion or excessive early shrinkage (with several h of application) that was typically greater than .635 cm (1/4 inch) in either direction. Any of these conditions can compromise the integrity of the protective EPDM layer, resulting in a leaky roof. The two polyisocyanurate boards absorb minimal amounts of water and showed no evidence of expansion or shrinkage. TABLE IV Type of Board of Observations After Exhibition of Recovery fmonths Wood Fibers (1.27 cm (1/2 inch)), damp . smooth hygroscopic (easily penetrated). loss of flexural strength, traction and compression. presence of black and white powdery mildew and various molds Extruded Polystyrene (1/2 inch) (more than one experiment) Buckling between areas subject as a result of expansion Shrinkage (greater than .635cm (1/4 inch) plus Occasionally post expansion without evidence of water absorption TABLE IV (Cont.) Type of Observation Board After Recovery Exhibition Four Months Polyisocyanurate with polypropylene / fiberglass coating Light absorption without evidence of expansion or shrinkage Polyisocyanurate with latex polymer / glass fiber filler coating Light absorption of water without evidence of expansion or shrinkage Thus, it should be evident that the method of the present invention is highly effective for putting back tecos. for laying new roofs it can be practiced with the variety of boards 10 which fall within the scope of the present invention. Based on the above description, it should now be apparent that the use of laminated boards described herein will carry out the previously established objectives. Therefore, it will be understood that any apparent variations fall within the scope of the claimed invention and thus the selection of specific component elements can be determined without departing from the spirit of the invention described and illustrated herein. In particular, boards according to the present invention are not necessarily limited to those having an isocyanurate or polyurethane foam core. Furthermore, as noted above, the composition of the polymer coating can be varied, particularly with the use of optional fillers. In this way, the scope of the invention will include all modifications and variations that fall within the scope of the appended claims.

Claims (10)

1. REIVINPICACI0W3BS 1. A method for relocating a roof, characterized in that it comprises: applying laminated recovery boards to a roof platform, the recovery boards comprise a foam core selected from the group consisting of polyurethane, polyisocyanurate and mixtures thereof, and first and second coatings, between which the foam core is walled, the coatings comprise a polymer sheet containing reinforcing material selected from the group consisting of glass strands, glass fibers and mixtures thereof, wherein the polymer sheet it is chosen from the group consisting of polypropylene and polymer latexes; and apply a protective layer to the weather on the recovery boards.
2. 2. A method for relocating a roof, according to claim 1, characterized in that the coatings are essentially devoid of any organic felt materials.
3. 3. A method for relocating a roof, according to claim 1, characterized in that the coating further comprises a filling selected from the group consisting of clay, mica, talc, lime, gypsum, aluminum trihydrate, antimony oxide, cellulose fibers, plastic polymer fibers and their mixtures.
4. 4. A method for relocating a roof, according to claim 3, characterized in that the filler comprises from about 0 to about 5,000 parts by weight per 100 parts by weight of the polymer sheet.
5. 5. A method for relocating a roof, according to claim 1, characterized in that the foam core has an approximate index of 250.
6. 6. A method for relocating a roof, in accordance with claim 1, characterized because the polymer latexes are chosen from the group consisting of styrene-butadiene rubber, polyvinyl chloride, polyvinyl alcohol and mixtures thereof.
7. A method for relocating a roof, according to claim 1, characterized in that the first and second coatings have a thickness in the range of between about .0254 cm (.01 inch) and about .381 cm (.15). inch).
8. A method for repositioning a roof, according to claim 1, characterized in that the step of applying laminated recovery boards to a roof platform comprises placing the laminated recovery boards in adjacent parallel or staggered sections that border each other .
9. 9. A method for relocating a roof, according to claim 1, characterized in that the weatherproof protective layer is selected from the group consisting of modified bitumen, and EPDM roofing membranes. A method for replacing a roof, according to claim 1, characterized in that it also comprises the step of applying another layer on the protective layer outdoors is selected from the group consisting of gravel, river stones and mixtures thereof .