MXPA01005711A - Storm proof roofing material - Google Patents

Abstract

An asphalt-based roofing material (68) includes a substrate (12) with an asphalt coating (74), a protective coating (70) adhered to the upper surface (80) of the asphalt coating (74), a layer of granules (72) adhered to the protective coating (70), and a web (132) bonded to the lower region (78) of the asphalt coating (74). A method of manufacturing a roofing material (68) includes coating a substrate (12) with an asphalt coating (74), applying a protective coating (70) to the upper surface (80) of the asphalt coating (74), applying a layer of granules (72) to the protective coating (70), and applying a web (132) to the lower region (78) of the asphalt coating (74).

Description

STORM PROOF ROOF MATERIAL TECHNICAL FIELD AND APPLICABILITY INDUSTRIAL OF THE INVENTION This invention relates to roofing materials, based on asphalt, and, in particular, to a roofing material having improved durability and impact resistance, to withstand the destructive forces of storms.

BACKGROUND OF THE INVENTION Roofing materials, based on asphalt, such as roof tiles, for sliding roofs and commercial roofs, are installed on the upper parts of buildings to provide protection for the elements. Typically, the roofing material is constructed of a substrate, such as a fiberglass mat, or an organic felt, an asphalt coating on the substrate and a surface layer of granules embedded in the asphalt coating. The constructions of the typical material are adequate in most circumstances. However, sometimes the roofing material is subjected to environmental conditions that can damage the roofing material. For example, storms are responsible for billions of dollars in damage to roofing materials every year. During storms, hail grains can make an impact with the roof material, which can cause tears or punctures in this roofing material. The hail impact can also cause an immediate loss of some granules from the impact areas of the roof material and the subsequent loss of granules from those areas over time. The loss of granules creates an unattractive appearance and leaves an asphalt coating in those areas, unprotected from the effects of degradation of the elements. Therefore, there is a need for a roofing material that has the improved ability to withstand the destructive forces of storms. The prior art does not adequately address the need for a storm-proof roofing material. For example, US Patents Nos. 5,380,552 and 5,516,573, both issued to George et al., Disclose a method for improving the adhesion of granules to roof tiles by spraying a thin stream of low viscosity adhesive to Cover 50 to 75% of the surface of the asphalt coating, before applying the granules. The patents teach that the loss of granules is caused by moisture that alters the bond between the granule and the asphalt coating. There is no suggestion that this loss of granules can be related to changes in the asphalt coating over time, or that the coating, in sufficient form, of the asphalt with an adhesive can reduce these changes and the resulting loss of granules. It is known to apply to a surface coating on a roof, after the roof tiles have been installed, to protect them from the loss of granules and other damages. Unfortunately, surface coatings require additional labor after roofing is installed, which is relatively expensive, and can create safety problems by producing a smooth roof. Several patents reveal roofing materials constructed with multiple substrates. For example, U.S. Patent No. 5,326,797, issued to Zimmerman et al, discloses a roof tile that includes an upper glass fiber mat and a polyester bottom mat. The patent refers to a fire-resistant tile and makes no mention of an improved impact resistance. There is also no suggestion to the improved bond between the polyester mat and the asphalt coating. U.S. Patent No. 5,571,596, issued to Johnson, discloses a roof tile, which includes a top layer of directional fibers, such as Keviar fabric, a middle layer of a fibrous mat material, such as a fiber mat of glass, and a lower layer of directional fibers, such as glass fabric E. The upper fiber layer is described as being important to protect the tile from damage to the impact of hail. The lower layer of glass fabric E is not effective in improving the impact resistance of the tile. U.S. Patent No. 5,822,943, issued to Frankoski et al., Discloses a roof tile covered with asphalt, which includes a canvas and a mat. The canvas is attached to the mat with adhesive; there is no suggestion of improved bond between the canvas and the asphalt coating. A canvas is not very effective in improving the impact resistance of the tile. A magazine article, "Impact Resistance Ballistic SMA and Spectra Hybrid Graphite Compounds, "Journal of Reinforced Plastics and Composites, Vol. 17, 2/1998, by Ellis et al., Discloses the placement of fibers that absorb energy on the back surface of a graphite compound. The fibers are found to provide only a slight improvement in the impact resistance of the composite.The journal article is not related to roofing materials.

It is known to manufacture roofing materials with rubber-modified asphalt to provide some improvement in impact resistance. Unfortunately, roofing materials made with rubber modified asphalt are more difficult to manufacture, handle, store and install, and they are more expensive than roofing materials obtained with conventional asphalt roofing. Also, asphalt shingles modified with rubber, are not very effective in resisting impacts. Therefore, there is a need for a roofing material that has improved durability and impact resistance to better resist the destructive forces of storms.

COMPENDIUM OF THE INVENTION The above objects, like others not specifically listed, are achieved by an asphalt-based roofing material, in accordance with the present invention. The roofing material includes a substrate cd with an asphalt cng, a protective cng, adhered to the upper surface of the asphalt cng, a surface layer of granules, adhered to the protective cng,. and a band attached to the lower region of the asphalt cng. The combination of the protective cng and the band provides a roofing material, which has improved durability and impact resistance. As a result, the roofing material is better able to withstand the destructive forces associated with storms. In another embodiment, the roofing material includes a substrate cd with asphalt, a protective cng adhered to the upper surface of the asphalt cng and a surface layer of granules adhered to the protective cng. This protective cng covers at least 80% of the top surface of the asphalt cng on the exposed portion of the roofing material. The present invention relates to a method for manufacturing a storm-proof roofing material. The method includes the steps of cng a substrate with an asphalt cng, applying a protective cng to the upper surface of the asphalt cng, applying a surface layer of granules to the protective cng and applying a strip to the lower region of the asphalt cng. In another embodiment, the method includes the steps of applying a band to a substrate, cng the substrate and the band with an asphalt cng, where the band is in contact with the lower region of the asphalt cng, applying a protective cng to the Top surface of the asphalt cng and apply a surface layer of granules to the protective cng.

In another embodiment, the method includes the steps of cng a substrate with an asphalt cng, moving the substrate, cd with asphalt, at a speed of at least about 61 meters / minute, passing an application device, to apply a continuous layer of the protective cng to the upper surface of the asphalt cng, and applying a surface layer of granules to the protective cng. Rapid movement of the asphalt-cd substrate creates a boundary layer of air on the top surface of the asphalt cng, which can create discontinuities in the protective cng. The applicator is positioned sufficiently close to the top surface of the asphalt cng to minimize the boundary layer and thereby substantially reduce discontinuities in the protective cng. In a further embodiment, the method includes the steps of cng a substrate with an asphalt cng, supplying a solid or fused film of a protective cng material, applying the film to the upper surface of the asphalt cng and applying a surface layer of asphalt. granules to the movie. Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in the light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic elevation view of the apparatus for manufacturing a roofing material, based on asphalt, according to the invention; Figure 2 is a perspective view of part of the manufacturing apparatus of Figure 1, showing a device that applies films of the protective coating on the upper surface of a sheet coated with asphalt; Figure 3 is a cross-sectional view of an alternative embodiment of a device that applies a protective coating film on the upper surface of a sheet coated with asphalt; Figure 4 is an enlarged cross-sectional view of a roofing material, based on asphalt, according to the invention; Figure 5 is a more elongated cross-sectional view of the upper portion of a roofing material, based on asphalt, according to the invention; Figure 6 is a perspective view of a roof tile of the prior art, installed on a roof, showing a loss of granules after a period of time, caused by impacts on the roof tile; Figure 7 is a perspective view of a roof tile, according to the invention, installed on a roof, showing that there is no substantial loss of granules over the same period of time, after impact; Figure 8 is a perspective view of part of the manufacturing apparatus of Figure 1, showing an apparatus for applying strips to the underside of a sheet of the substrate coated with asphalt; Figure 9 is a schematic view, in elevation, of an alternative embodiment of the apparatus of the Figure 8, showing the strip being applied to the lower surface of a substrate, before coating the strip and the substrate with the asphalt coating; Figure 10 is an enlarged perspective view, partially in cross section, of a two-component band, for use in the asphalt-based roof material, according to the invention; Figure 11 is an enlarged, enlarged cross-sectional view of the strip of Figure 10, in contact with an asphalt coating, showing the second component of the inter-blend belt with a portion of the asphalt coating; Figure 12 is an enlarged perspective view, partially in cross section, of a wrap / core fiber of a strip, for use in the asphalt-based roofing material, according to the invention; Figure 13 is an enlarged, enlarged cross-sectional view of the wrapping / core fiber of Figure 12, surrounded by an asphalt coating, showing the sheath of the inter-mixed fiber by melting with a portion of the asphalt overlay; Figure 14 is a top view of a sheet of roofing material, made with the apparatus of Figure 1, showing the roofing material, after cutting, but before separation in roof tiles; Figure 15 is a perspective view of several roof tiles, with three projections, according to the invention, installed on the side of a roof; Figure 16 is a perspective view of an easel-type roof tile, according to the invention, installed on the edge of a roof; and Figure 17 is a perspective view of a laminated roof tile, according to the invention.

DETAILED DESCRIPTION AND PREFERRED MODALITIES OF THE INVENTION Referring now to the drawings, there is shown in Figure 1, an apparatus 10 for manufacturing a roofing material, based on asphalt, according to the invention. The illustrated manufacturing process involves passing a web 12 in a machine direction (indi- cated by the arrows) through a series of manufacturing operations. The sheet is usually moved at a speed of approximately 61 meters / minute, and typically at a speed in the range between 137 meters / minute and 244 meters / minute. Although the invention is shown and described in terms of a continuous process, it should be understood that this invention can also be practiced in a batch process, using discrete lengths of materials, instead of continuous sheets. In a first stage of the manufacturing process, a continuous sheet 12 of the substrate is unwound from a roll 14. The substrate can be any type known for use in reinforcing asphalt-based roofing materials, such as a band, canvas or felt of fibrous materials, for example mineral fibers, cellulose fibers, rag fibers, mixtures of mineral and synthetic fibers, or the like. Combinations of materials can also be used in the substrate. Preferably, the substrate is a nonwoven web of glass fibers. The sheet of the substrate is passed from the roll through an accumulator 16. This accumulator allows the time for the connection of one roll of substrate to another, during this time, the substrate inside the accumulator is fed to the manufacturing process, so that this splice does not interrupt the manufacture. Next, the sheet is passed through a coater 18, where an asphalt coating is applied to the sheet. The asphalt coating can be applied in any suitable manner. In the illustrated embodiment, the sheet is immersed in a supply of a hot molten asphalt coating to completely cover the sheet with the sticky coating. However, in another embodiment, the asphalt coating can be sprayed on, rolled on, or applied to the sheet by other means. When an organic felt is used as the substrate, it may be convenient to first saturate the felt with a saturation asphalt, and then coat the upper and lower surfaces of the felt with an asphalt coating containing a filler. The term "asphalt coating" means any type of bituminous material, suitable for use in a roofing material, such as asphalts, tars, pitches, or mixtures thereof. The asphalt can be a manufactured asphalt, produced by the refining of petroleum or an asphalt that occurs naturally. The asphalt coating may include various additives and / or modifiers, such as inorganic fillers or mineral stabilizers, organic materials, such as polymers, recycled streams or ground polish rubber. Preferably the asphalt coating contains an asphalt and an inorganic filler or mineral stabilizer. Unlike some previous roofing materials, there is no need to modify the asphalt with rubber or similar polymers, to improve the durability of the roofing material. The roofing material of the present invention is provided with improved durability by the application of a protective coating to the upper surfaces of the asphalt coating. One aspect of improved durability is a reduction in granule loss, which can be caused by hail grains during storms, in addition to the natural environment. As shown in Figure 1, sheet 20, coated with asphalt, is passed under an applicator 22, where a protective coating is applied to the upper surface of the asphalt coating. The sheet is then passed under a granule distributor 24, for the application of granules to the protective coating. After depositing the granules, the sheet is turned around a slate drum 26, to press the granules into the asphalt coating and to temporarily invert the sheet. The protective coating can be applied to the upper surface of the asphalt coating by any suitable method to form a layer that is effective in improving the durability of the roofing material. In a preferred embodiment, the protective coating is applied as a film, which may be a solid, semi-solid or fused film. Figure 2 illustrates an applicator 22 for applying a pair of molten protective film 28 onto the upper surface 30 of the asphalt coated sheet 20. The sheet may include single or multiple lanes. Four lanes 32 are shown in the illustrated mode (indicated by dotted lines) so the sheet can be cut into roof tiles. In the illustrated mode, each of the rails includes a sizing portion 34, which is normally exposed to the elements, when the roofing material is installed on a roof, and an overlapping portion 36 that is normally covered by adjacent shingles when the tile is installed of ceiling sips the same. Preferably, the films of the protective coating are applied to the sizing portions of the sheet, but not to the overlapping portions. The application of the protective coating to just the sizing portions of the sheet, provides improved durability to the portion of the roof tile exposed to the elements on a roof, while minimizing the overall cost of the roofing material. However, a film of a protective coating can also be applied to cover the entire sheet. The application device, shown in Figure 2, includes a support shoe 38, for the purpose described later. Single or multiple dies can be mounted in the openings in the support shoe, two dies 40 in the illustrated embodiment, and secured by fasteners, such as clamps, 42. Each of the dies includes a slit 44, which faces downwardly. to the asphalt coating and is thus oriented transversely to the direction 46 of movement of the sheet. The dies are supplied through heated feed hoses 48, with the molten protective coating, which is pumped from a storage tank (not shown). The molten protective coating is extruded as a film 28 through the slit of each die on the upper surface of the asphalt coating. The support shoe prevents the formation of rims or wakes in the protective coating along the sides of the slit, during the application of the film.

It was found that rapid movement of the asphalt-coated sheet creates a boundary layer of air on the upper surface of the sheet, and that when the protective coating is applied, this boundary layer can cause the protective coating to be discontinuous across the surface. of intended application, instead of continuous. In a preferred embodiment, the applicator is placed sufficiently close to the upper surface of the asphalt coating to minimize the boundary layer and thereby significantly reduce the discontinuities in the protective coating. Preferably, the protective coating forms a layer that is at least 90% continuous (no more than 10% open areas) and, more preferably, forms a substantially complete continuous layer. As shown in Figure 2, the support shoe 38 and the punches 40 of the applicator are placed just in contact with the upper surface 30 of the sheet 20 coated with asphalt. Preferably, the applicator is placed within approximately 0.254 cm of the top surface. Figure 3 illustrates another preferred applicator 50, for applying a protective film 52 on the upper surface 54 of a sheet 56 coated with asphalt. A die 58 is mounted in an assembly 60 positioned above the sheet. This punch includes a groove 62 that faces downwards to the asphalt coating, and which is oriented transversely to the direction 64 of movement of the sheet. The die and the slit are placed at a distance D within about 0.254 cm from the top surface of the sheet. The die is supplied through the supply line 66 heated with the molten protective coating pumped from a storage tank (not shown). The molten protective coating is extruded through the slit like film 52, onto the upper surface of the asphalt coated sheet. Many other methods can be used to apply the protective coating to the top surface of the asphalt coating. One method is to unwind a film, previously extruded, from the protective coating material on the asphalt coated sheet. Another method is to add the protective coating material, in the form of particles, to the upper surface of the asphalt coated sheet, and then heat the protective coating material to melt and cause it to flow into a substantially continuous layer. One more method is the pre-mixing of the protective coating material in the particulate form in an asphalt coating, so that the protective coating material melts and separates into phases of the asphalt coating, when the asphalt coating is heated, to provide a substantially continuous layer on the asphalt coating. Other suitable methods include spray coating and roller coating. Preferably, the protective coating is sufficiently fluid when the granules are applied and flows partially around the granules to adhere it to a coating. In a preferred embodiment, the protective coating is applied immediately after applying the asphalt coating and immediately before applying the granules. Preferably, the protective coating covers at least 80% of the upper surface of the asphalt coating, in the portion of the roofing material that is exposed in this roof. More preferably, the protective coating substantially completely covers the top surface of the asphalt coating in the exposed portion. As shown in Figure 2, the films of the protective coating 28 completely cover the sizing (exposed) portions 34 of the roofing material. The protective coating preferably has an average thickness of at least 25.4 microns and more preferably at least about 76 microns. However, the protective coating is not so thick that it covers the granules and leaves a shiny appearance on the surface of the roofing material. Preferably, the protective coating has an average thickness no greater than about 1.5 mm. The covering of the asphalt coating with the protective coating reduces the loss of granules. Figures 4 and 5 illustrate a roofing material 68 according to the invention, with an applied protective coating 70 and a layer of granules 72. The roofing material includes a substrate 12 which is coated with a coating 74 of asphalt. This asphalt coating includes an upper region 76 which is placed above the substrate 12 when the roofing material is installed thereon, and a lower region 78 which is placed below the substrate. The upper region includes an upper surface 80. The protective coating 70 adheres to the upper surface of the asphalt coating. The surface layer of granules 72 adheres to the protective coating. It is believed that the protective coating improves the adhesion of the granules by several possible different mechanisms. The granules can adhere more strongly to the protective coating than to the asphalt coating, due to the different protective coating compositions and the asphalt coating. In some embodiments, the protective coating completely encloses a median layer of granules to adhere these granules to the roofing material. Preferably, about 0.5 to 6% of the total granules are enclosed. In Figure 4, the protective coating 70 encloses the granules 82, 84, 86 and 88 and in Figure 5, the protective coating 70 encloses the granules 90 and 92. The protective coating also adheres strongly to the asphalt coating. In the illustrated embodiment, a region 94 between phases comprises a portion of the protective coating 70, which has been intermixed with a portion of the asphalt coating 74 by melting and mixing, due to the partial miscibility of the protective coating with the asphalt coating. The mixed medium strongly adheres the protective coating to the asphalt coating. Some protective coating materials are miscible with the asphalt coating, and others are not miscible. In some embodiments of the invention, the protective coating adheres strongly to the asphalt coating, without intermixing. As shown in the drawings, the granules 72 have been pressed into the protective coating 70. Usually, at least a portion of the granules penetrate the asphalt coating 74. "Penetrate" means that a granule extends past a line 95 of the asphalt coating, which is an average top surface of the asphalt overlay 74. In Figure 4, the granules 96, 98, 84, 86 and 100 penetrate the asphalt coating; and in Figure 5, the granules 90, 102 and 104 penetrate the asphalt coating. In some embodiments of the invention, a substantially continuous layer of the protective coating is maintained between the asphalt coating and the granules that penetrate this asphalt coating. In Figure 4, layers 110, 112 and 114 of the protective coating are maintained between the granules 96, 98 and 86 and the asphalt coating, and in Figure 5, a layer 116 is maintained between the granules 104 and the asphalt coating. . It is believed in advance that a granule was pressed through the protective coating layer in the asphalt coating, the protective coating layer may not be maintained between the granules and the asphalt coating. Preferably, a substantially continuous layer of the protective coating is maintained between the asphalt coating and at least 30% of the granules that penetrate the asphalt coating. The continuous layer of the protective coating around the granules increases the adhesion of the granules to the roofing material. Additionally, the protective coating can provide a seal to prevent external moisture from flowing through the granules in the asphalt coating. This can help prevent degradation of roofing material. In Figure 4, the protective coating can provide a seal to prevent moisture from flowing around the granule 100 to the asphalt coating, although the granule penetrates the asphalt coating. This protective coating forms an airtight seal completely around the perimeter of the granule. Similarly, in Figure 5, the protective coating provides a seal around the granule 102. The protective coating can be any material suitable for forming a layer that is effective in improving the durability of the roofing material, such as any type of thermoplastic material, thermostable or polymer based on asphalt. In a preferred embodiment, the polymeric material functions as an adhesive. Similarly, the adhesive can include any type of thermoplastic, thermoset or asphalt-based adhesive that is effective in adhering the granules to the asphalt coating. Examples of suitable hot-melt adhesives include copolymers of ethylene and vinyl acetate, copolymers of ethylene and ethyl acetate, ethylene-n-butylacrylate polymers, ethylene methacrylate polymers, block or styrene graft copolymers -isoprene-styrene, styrene-butadiene-styrene block or graft copolymers, other block or graft copolymers containing styrene, polyamide terpolymers, hydrocarbon rubbers, polyethylenes, polyesters, polyurethanes, siloxanes and mixtures / combinations thereof materials. Preferred adhesives for use in the invention are flexible copolymers of ethylene and vinyl acetate, copolymers of ethylene and vinyl acetate modified with flexible styrene-butadiene-styrene block copolymers, and tackified polyethylenes. Preferably, the adhesive is selected to adhere to the roof granules, predominantly by polar junction. For example, ethylene vinyl acetate copolymers adhere to conventional coated (painted) granules, predominantly by polar junction. The adhesive can be modified with materials, such as styrene-butadiene polymers, polyolefin polymers, styrene-isoprene polymers, tackifying resins, petroleum derivatives, tackifying resins derived from rosin, tackifying resins derived from the terpene, paraffin waxes and oils, microcrystalline waxes and oils, and naphthenic waxes and oils. A stabilizer may be added to the protective coating to adjust this protective coating to specialized conditions, such as extreme exposure to ultraviolet light, solar radiation and / or temperature. The protective coating may also contain other additives, such as algicides, fungicides or pigments.

Figures 6 and 7 illustrate the effect of the protective coating in providing improved durability to a roof tile, particularly improved retention of the granules. Figure 6 shows a roof tile 118 of the prior art, without the protective coating, installed on the roof 120. The roof tile has been subjected to impacts in several areas 122, creating depressions in those areas. After a period of time, the granules in the impact areas lose their adhesion and are lost from the roofing material. The loss of granules leaves the asphalt coating in the areas of impact exposed to the elements. The exposed asphalt coating becomes eroded by the effects of the environment on the asphalt coating. The resulting roof tile has an unattractive appearance and, finally, will no longer be effective in protecting the building. In contrast, Figure 7 shows a roof tile 124 with a protective coating 70, in accordance with the present invention, installed on a roof 126. The roof tile has also been subjected to impacts in various areas 128, creating depressions in these areas. areas. Unlike the roof tile of the prior art, the roof tile with the protective coating retains the granules 130 in the impact areas after the same period of time. The asphalt coating in these areas is protected by the granules, so the roof tile maintains its effectiveness and attractive appearance. Referring again to Figure 1, the roofing material of the present invention also includes a band 132. This band is selected from the type of band, and is placed and joined in such a manner as to supply the roofing material with a Improved impact resistance to a variety of them. This improved impact resistance eliminates the occurrence of perforations or tears in the roofing material, caused by impacts and thus maintains the integrity of the roofing material. This roofing material retains its ability to protect the building from the elements, so, for example, the escape of water is avoided. As shown in Figure 1, the web 132 is unwound from a roll 134 on the bottom surface of the sheet 20, while the sheet is inverted in the slate drum 26. Figure 8 illustrates a preferred apparatus 136 for unwinding continuous webs 132 on the lower surface 138 of the sheet 20. The bands are unwound from the rolls 140. The bands are fed around the first and second guide bars, 142 and 144, to maintain tension in the bands. The second guide bar 144 is placed adjacent and parallel with the slate drum 26, so the bands are properly aligned with the sheet when they are fed onto the lower surface of the sheet. As the sheet is turned around the slate drum, the asphalt coating is still hot, soft and sticky, so the bands adhere to the bottom surface of the asphalt coating and are pulled around the slate drum along with the sheet. Preferably the webs are applied to the bottom surface of the sheet in the sizing portions 34, but not in the overlapping portions 36. The application of the web below just the sizing portion of the roofing material provides improved impact resistance to the portion of the roofing material exposed to the elements in a roof, while minimizing the overall cost of the roofing material. In an alternative embodiment, shown in Figure 9, the web 132 is unwound from a roll 134 'on the bottom surface of the sheet 12 of the substrate, before coating both the web and the substrate with an asphalt coating. Preferably, the web is attached to the substrate before the asphalt coating step, or intermittently or continuously, by its lengths. Any suitable joining apparatus 146 can be used to join the band to the substrate. Some examples of joining methods include heat sealing, ultrasonic welding, pressure sensitive or hot melt adhesives, electrostatic bonding and physical interlacing by such means as needles or sewing. The bonding of the band to the substrate fixes the position of this band relative to the substrate in both the machine and transverse directions of the sheet. The joint also helps to minimize any shrinkage or wrinkling of the band that might occur during the asphalt coating stage. Referring again to Figure 4, the band 132 joins the lower region 78 of the asphalt coating 74. Bonding the band to the lower region of the asphalt coating, rather than to the upper region 76, has been found to provide unexpected improvement in resistance to a variety of impacts. Unlike the roof tile described in U.S. Patent No. 5,571,596 to Johnson, there is no need to add a layer of impact-resistant material to the upper region of the asphalt coating. The band can be attached to the asphalt coating at any location in the lower region. The "lower region" 78 of the asphalt shroud 74 includes any location between the bottom surface 148 of the substrate 12 and the bottom surface 150 of the asphalt shroud. In the preferred embodiment, shown in Figure 4, the band is attached to the lower surface of the asphalt coating. It has been found that the bonding of the strip to the lower surface of the asphalt coating achieves superior impact resistance. Preferably, the roofing material of the present invention includes a strong bond between the strip and the asphalt coating, to ensure that the strip does not separate from the asphalt coating. If the band is separated from the asphalt coating, it is not effective in dissipating the energy of an impact on the roofing material. The strong bond is achieved by melting the band and the asphalt coating. Specifically, a portion of the strip and the asphalt coating are melt intermingled, thereby melting the strip and the asphalt coating. Intermixing "includes any type of internal, physical and / or chemical mixture of the strip and the asphalt coating, to provide mechanical strength and / or strong chemical bonding.As shown in Figure 4, the roofing material includes an internal phase region 152, where internal fusion mixing has occurred, between a portion of the band 132 and a portion of the lower region 78 of the asphalt coating, due to the partial miscibility of the cast strip and the asphalt coating The internal phase region is usually an inhomogeneous region, which includes various concentrations of molten asphalt coating, the partially melted or fully fused band, and mixtures of the molten asphalt coating and the cast band. composition different from either the remaining portion 153 of the band or the remaining portion 155 of the lower region 78 of the asphalt coating. Internal zcla can include various degrees of mixing between the band and the asphalt coating. In the illustrated embodiment, the internal mixture also includes an irregular interface 154 or boundary between the region of the internal phase 152 and the pure asphalt coating 155. The irregular interface 154 is comprised of ridges and valleys that have resulted from interpenetration between the Interphase region and pure asphalt coating. The irregular interface increases the bond between the band and the asphalt coating. A portion 153 of the band 132 may not have an intermixed with the asphalt coating, thereby forming an interface 157, between the interface region 152 and the portion 153 of the band. In a preferred embodiment, the fusion of the band and the asphalt coating is facilitated by the use of a two-component band. This band of two components is comprised of a first component, which has a first melting point, and a second component, which has a second melting point, which is less than the first melting point. During the manufacture of the roofing material, at least a portion of the second component of intermingling with the asphalt coating by melting, thus melting the strip and the asphalt coating. "At least one portion" means that some or all of the second component is mixed with the asphalt coating by melting. Some portion of the first component can also be intermixed by fusion, as long as the web sufficiently maintains its structure to be effective in improving the impact resistance of the roofing material. Preferably, the second component has a melting point at least 28 ° C lower than the melting point of the first component and, more preferably, at least about 56 ° C lower. The asphalt coating usually has a process temperature in the range between 163 and 232 ° C. Preferably, the second component has a melting point not higher than 204 ° C and more preferably not higher than 196 ° C, so at least a portion melts in contact with the asphalt coating. Preferably, the first component has a melting point of not less than about 177 ° C, so it remains substantially solid in contact with the asphalt coating. Figure 10 and 11 illustrates a two component film 156, which is useful as the band. As shown in Figure 10, the film comprises a first band 158 of a first component, laminated to a second layer 160 of a second component. As shown in Figure 11, the second layer 160 has been intermixed with the asphalt coating 74 by melting. In another embodiment, the band is comprised of two-component fibers. Preferably, the two component web is a non-woven web of sheath / core fibers. As shown in Figure 12, a wrap / core fiber 162 includes a core 164 comprised of a first component and a shell 166 comprised of a second component, which has a melting point lower than the melting point of the first component. As shown in Figure 13, the wrap 166 has been intermixed with the asphalt coating 74, by melting. A variety of different types of bands are suitable for use in the present invention. The material and structure of the band are chosen from those bands that are effective in improving the impact resistance of the roofing material. Specifically, the band is effective in dissipating the energy of an impact on the roofing material. Preferably, the material of the band has good tensile bending properties, so it can dissipate energy and impact. A glass mat is not suitable for use with the band, due to its limited elongation properties. Also, preferably, the structure of the band is substantially continuous in length and width, so it can transmit uninterrupted energy waves from the point of impact to the edges of the band. For this reason, a canvas is not preferred for use as the band. Preferably, the strip is also a material which has components that can be melted to the asphalt coating by having a portion of the strip melted and internally mixed with the asphalt coating. The components of the thermoplastic polymer are preferred for use in the web, because they are capable of partially melting in contact with the hot asphalt coating. On the other hand, the thermosetting polymer components will not melt in contact with the coating. Usually, the web material is miscible, at least partially, with the asphalt coating. Also preferably, the band can be cut cleanly and easily during the manufacturing process of the roofing material, such as when the sheet of the roofing material is cut into tiles and when the protrusions are cut into a tile. The clean cut means that there are no cords or other portions of the web material projecting from the edges of the cut roof material.

It is preferred that the web does not shrink substantially in contact with the hot asphalt coating, thus providing a total surface coverage. Also preferably, the web material has a coefficient of friction that prevents the roofing material from sliding out of the roof during installation. Some materials may be suitable for use as the band include mats, bands, films, fabrics, veils, canvases, similar structures or combinations of these materials. The mats include, for example, airlaid fabrics, networks and hydroentangled fibers,. The films include, for example, rigid polyvinyl chloride, flexible polyvinyl chloride, polycarbonate, ionomer resin (e.g. Surlyn®), and polyvinylidene chloride (e.g., Saran Wrap®). A preferred material for use as the web is a non-woven web of thermoplastic, two-component polymer fibers, such as the wrap / shell fibers described above. Preferred sheath / core fibers are commercially available from PGI Inc. Arkansas. For example, PGI 4103, PGI 4124 and PGI 4104 are nonwoven webs of sheath / core fibers, each fiber includes a core of polyethylene terephthalate and a polyethylene sheath. The wrappers of the fibers are heat bonded together in the band to hold the bands together. These products are available in a variety of non-woven forms, which include fluffed or densified shapes. A preferred form is densified at 33.9 grams per square meter. The sheath / core fiber web melts well to the asphalt coating. The band can be applied and fused to the lower region of the asphalt coating in any suitable manner. As described above, the preferred method is to coat the substrate with the asphalt coating and then apply the strip to the lower surface of the coating. A portion of the band melts in contact with the hot asphalt coating and, due to the partial miscibility of the band and the coating, intermixed with the coating to melt the band and the coating. It has been found that some types of band melt better if they are applied to the asphalt coated sheet, instead of the first one being applied to the substrate and then coated along with the substrate. Some types of band will melt too well in the asphalt coating device, which can cause them to shrink or tear. Another method of melting the band and the asphalt coating is to apply a band that does not initially fuse in contact with the coating, but partially fuses and intermixes with the coating then in the process of applying heat to the band and / or covering. Another method is to extrude a molten film of the web material onto the lower surface of the asphalt coated sheet and then solidify the band by cooling. Another method is to apply a strip to the asphalt coated sheet, where the strip is completely miscible with the asphalt coating, but where the heat history of the band limits the migration of the strip within the asphalt coating. Still another method is to mix the web material with the asphalt coating during the manufacture of the coating; When the asphalt coating is heated in a coating device, the material of the strip separates and migrates to the surface of the asphalt coating. Other suitable methods are also considered. It should be noted that the band can be manufactured separately before the tile manufacturing process, or it can be manufactured simultaneously with the manufacture of tiles. It should also be noted that the release tapes can be incorporated in part of the band, to facilitate the separation of the roof tiles from each other, after packing and transport. Alternatively, a release material, such as silicone, can be integrated into the band or parts of the band.

Referring again to Figure 1, after the web 132 is applied, the sheet 168 of the asphalt-based roofing material is reinverted and then cooled by any standard cooling apparatus 170, or allowed to cool to room temperature . The sheet of roofing material, based on asphalt, is then cut by a cutter 172 in individual tiles 174, in pieces for making laminated tiles or in suitable lengths for the commercial roof or the sliding roof. The roofing material is then picked up and packed. Figure 14 illustrates the sheet 168 of the roofing material after it has been cut into three roof tiles 174 with projections, but before separating the tiles from the sheet. Figure 15 illustrates several roof tiles 174 installed on the side of a roof 176. As shown in Figures 14 and 15, each roof tile includes a sizing (exposed) portion 176 and an overlapping portion (roof) 36 As indicated by the denser dot areas, the protective coating 70 is applied to the sizing portion, but not to the overlapping portion of each tile. The band is placed below the sizing portion, but not the overlap portion. Figure 15 illustrates a trestle roof tile 178, according to the invention, installed on the ridge 180 of a roof. The protective coating 70 and the band are applied to the tile, because the entire tile is exposed to the elements in the roof. Figure 17 illustrates a laminated roof tile 182, according to the invention. The laminated tile is comprised of two pieces of roofing material, an overlay 184 and an underlying 186, which are secured together by adhesive or other means. The laminated tile includes a sizing portion 188 and an overlap portion 190. As indicated by the denser dot area, the protective coating 70 is applied to the sizing portion, but not to the overlapping portion of the tile. The band is placed below the sizing portion of the underlying but not the overlap portion. It should be understood that, although the improved durability provided by the protective coating is described primarily in terms of the reduced loss of granules, the protective coating also provides many other advantages. For example, the protective coating can prevent or reduce fractures of the asphalt coating, which result from impacts on the roofing material. The improved durability provided by the protective coating can allow increased flexibility in selecting the composition and materials of the roofing material. The protective coating can provide a barrier to moisture, which reduces the potential for blistering and the growth of algae. The protective coating can reduce tile fissures in a roof and can partially heal any fissures that occur. The protective coating can provide a more uniform surface that can reduce shading. Additionally, the protective coating can reduce adhesion of tile bundles. Other advantages are also considered for the protective coating. The performance of the ability to walk and crawl is not adversely affected by the addition of the protective coating. Although the improved impact strength provided by the web is described primarily in terms of the impact strength of hail grains, the web can also provide improved resistance to other types of impact on the roofing material. This roofing material of the invention includes any type of material, such as tiles, with or without projections, laminated tiles of various models, commercial roofs and sliding roofs. The invention is intended to be applicable to any current or future model of roofing materials.

Granule Adhesion Test Ceiling tiles, which include different types of protective coatings, according to the invention, were tested on the adhesion of granules, compared to the same class of roof tiles without the protective coating (the "roof tile"). control"). Three different adhesives were tested as the protective coating: flexible copolymers of ethylene and vinyl acetate (Reynco 52-057, Reynolds Co.); copolymers of ethylene and vinyl acetate, modified with styrene-butadiene-styrene block copolymers (Reynco 52-146); and sticky polyethylene (Reynco 52-115). The adhesive was applied as a 127 micron thick film on three tiles with projections, in a standard manufacturing facility. The adhesive completely covered the intake portion of the roof tile. The tiles underwent an accelerated test to simulate the effects of the weather and the impact of the hail. The tiles were subjected to a 60-day exposure to alternative cycles of concentrated solar radiation and water sprays. The tiles were then cooled to 10 ° C and a test coupon from each tile was subjected to the UL 2218 impact of Class 4. A circle of 2.54 cm in diameter in the impact area was then inspected for the percentage of granules lost in the area. The control tile lost approximately 44% of the granules in the impact area. In contrast, the tile covered with ethylene vinyl acetate copolymers lost only 3% of the granules, the tile covered with copolymers of ethylene and vinyl acetate modified with SBS, lost about 5% of the granules and tile coated with polyethylene lost only 2% of the granules.

Impact Resistance Test The improved impact resistance of the roofing materials of the present invention was demonstrated by the use of a standard method, UL 2218, "Standards for the Impact Strength of Prepared Roof Cover Materials", Underwriters Laboratories, May 31, 1996. In this method, the roofing material was secured to a test cover, and a steel bag was dropped vertically through a tube onto the upper surface of the roofing material. This roofing material can be tested at four different impact force levels: Class 1 (the lowest impact force) through Class 4 (the highest impact force). The force of impact in different classes is varied by changing the diameter and weight of the steel ball, and the distance the ball falls. For example, the Class test uses a steel ball with a diameter of 32 mm, weighing 127 g, which is dropped by a distance of 3.7 meters, while the Class 4 test uses a steel ball with a diameter of 51 mm, which weighs 521 g, which is dropped by a distance of 6.1 meters. After impact, the roofing material was inverted and bent over a mandrel in both the machine and transverse directions, and the bottom surface of the roofing material was examined visually for any evidence of an opening or tear. A 5X amplification device can be used to facilitate the examination of the roofing material. If no evidence of openings is found, the roofing material passes the impact resistance test in the UL 2218 class tested. Preferably, a roofing material having a strip according to the present invention has an increased impact strength of at least two UL2218 classes compared to the same stripless roofing material. More preferably, the roofing material complies with UL 2218 Class 4 impact resistance standard. The principle and mode of operation of the invention in its preferred embodiments was described. However, it should be noted that the invention can be practiced otherwise to the one illustrated and described specifically, without departing from its scope.

Claims (17)

1. CLAIMS 1. A roofing material, based on asphalt, which includes a substrate coated with an asphalt coating and having a surface layer of granules, this asphalt coating includes an upper surface, above the substrate, the roofing material includes a portion, which is normally exposed when the roofing material is installed on a roof, wherein the improvement comprises: a protective coating, not of asphalt, adhered to the upper surface of the asphalt coating, this protective coating forms a layer, substantially Continuous, on the upper surface of the exposed portion of the roofing material, the surface layer of granules adheres to the protective coating.
2. 2. The roofing material according to claim 1, wherein the protective coating substantially covers the entire upper surface of the asphalt coating, in the exposed portion of this roofing material.
3. 3. The roofing material according to claim 1, wherein the protective coating has an average thickness of about 25.4 microns.
4. 4. The roofing material according to claim 1, wherein the protective coating comprises an adhesive.
5. 5. The roofing material according to claim 4, wherein the adhesive is selected from the group consisting of copolymers of ethylene and vinyl acetate, copolymers of ethylene and vinyl acetate modified with styrene-butadiene-styrene block copolymers, copolymers of ethylene and ethyl acetate, ethylene-n-butylacrylate polymers, ethylene methacrylate polymers, styrene-isoprene-styrene block or graft copolymers, styrene-butadiene-styrene block or graft copolymers, other block copolymers or grafts containing styrene, polyamide terpolymers, hydrocarbon rubbers, polyethylenes, polyesters, polyurethanes, siloxanes, and mixtures of these materials.
6. 6. The roofing material according to claim 1, in which, after aging for 60 days of exposure to alternate cycles of concentrated solar radiation and water spray, then cooling to 10 ° C, and subjecting to a UL 2218 impact test. Class 4 exhibits improved adhesion of the granules, as measured by at least 30% loss of granules in the impact area, compared to the same roofing material without the protective cover.
7. 7. The roofing material according to claim 1, wherein the asphalt coating further includes a lower region beneath the substrate, and where the roofing material further includes a band, attached to the lower region of the asphalt coating, the band improves the impact resistance of the roofing material so that, when tested under the UL 2218 impact strength test, the roofing material exhibits an improvement in the impact strength of at least two classes of UL 2218, compared to the same material of roof without the band.
8. 8. The roofing material according to claim 1, wherein at least a portion of the granules penetrate the asphalt coating, and where the protective coating provides a seal to prevent moisture from flowing around the granules to the asphalt covering. .
9. 9. A method for manufacturing a roofing material, based on asphalt, which includes coating a substrate with an asphalt coating, and applying a surface layer of granules, this asphalt coating includes an upper surface, above the substrate, the roofing material includes a portion that is normally exposed when the roofing material is installed on a roof, where the improvement comprises: applying a protective coating, not an asphalt, to the upper surface of the asphalt coating, to form a substantially continuous layer on the roof. upper surface in the exposed portion of the roofing material, and apply the surface layer of granules to the protective coating.
10. 10. The method according to claim 9, wherein the protective coating is applied to cover substantially all of the upper surface of the asphalt coating, in the exposed portion of the roofing material.
11. 11. The method according to claim 9, wherein the step of applying the protective coating comprises applying an adhesive.
12. 12. The method according to claim 9, wherein the asphalt coating further includes a lower region, below the substrate, and wherein the method further comprises applying a strip to the lower region of the asphalt coating, this band improves the impact resistance of the roofing material, so that, when tested under the impact resistance test, UL 2218, the roofing material exhibits an improvement in impact resistance of at least two classes of UL 2218, compared to the same material of roof without the band.
13. 13. The method according to claim 12, wherein the lower region of the asphalt coating includes a lower surface, and where the web is applied and fused to the lower surface.
14. 14. The method according to claim 9, wherein the step of applying the protective coating comprises moving the coated substrate with asphalt at a rate of at least about 61 meters per minute, passing an application device, to apply a protective coating layer to the top surface of the asphalt coating, the movement of the substrate coated with asphalt creates a boundary layer of air on the top surface of the asphalt coating, which can cause discontinuities in the protective coating layer, where the application device is placed sufficiently close to the top surface of the asphalt coating, to minimize the boundary layer and thus form a protective coating layer, which is at least approximately 90% continuous.
15. 15. The method according to claim 14, wherein the application device is placed within approximately 0.254 cm of the top surface of the asphalt coating.
16. 16. The method according to claim 9, wherein the step of applying the protective coating comprises supplying a film of the protective coating and applying the film to the upper surface of the asphalt coating.
17. 17. The method according to claim 9, wherein the step of applying the protective coating comprises mixing a protective coating material with an asphalt coating, coating the substrate with the mixture of the protective coating material and the asphalt coating, and heating the mixing to cause the protective coating material to separate from the asphalt coating and form a layer on the upper surface of the asphalt coating.