Stock material or miscellaneous articles – Composite – Of bituminous or tarry residue
Reexamination Certificate
1999-10-04
2001-05-08
Watkins, III, William P. (Department: 1772)
Stock material or miscellaneous articles
Composite
Of bituminous or tarry residue
C052SDIG009, C052SDIG001, C052S518000, C428S002000, C428S143000, C428S490000, C428S491000, C428S496000, C428S903300, C442S085000, C442S086000, C442S367000, C442S414000
Reexamination Certificate
active
06228503
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a recycled roofing material and method of manufacturing the same and in particular, to a roofing material which includes the addition of cellulose fiber, which is obtained from ground up, reclaimed roofing materials to asphalt roofing materials.
BACKGROUND OF THE INVENTION
Considerable waste is involved with the manufacturing and use of asphalt roofing materials, such as shingles and rolled roofing membranes. For example, each new shingle has cut out tabs that are removed and discarded. Old shingle material removed from old buildings also provides a significant amount of roofing material waste.
Waste generated from roofing materials, such as asphalt shingles, presents a significant environmental concern because of the composition of the roofing material. Typical shingles are composed of a cellulose and/or fiberglass fiber mat, a saturating asphalt within the mat, an asphalt coating on the asphalt saturated mat and granules disposed on the coating. Such materials are difficult to break down and have typically required complex recycling processes.
One asphalt shingle recycling process is disclosed in U.S. Pat. No. 5,848,755 which is commonly owned by the assignee of the present invention and is fully incorporated herein by reference. The recycling system disclosed in the referenced patent application is capable of recycling asphalt roofing material and reducing granules, cellulose and fiberglass fibers and other particles in the asphalt roofing material to a fine mesh that can be maintained in suspension in liquid asphalt for later reuse.
Almost all roofing products that are used on sloped roofs use oxidized asphalt. Oxidized asphalt is asphalt that has been polymerized to increase its melt point. The oxidation/polymerization process increases the melt from approximately 100° F. (Fahrenheit) to over 200° F. In prior art asphalt roofing manufacturing processes, asphalt is oxidized by blowing high pressurized air into a tank of asphalt heated to approximately 400° F. An exothermic reaction occurs, which polymerizes the asphalt. The lighter fractions of the asphalt are driven off as a byproduct of the reaction. This process, however, is very expensive because of the energy costs associated with heating the asphalt to the required polymerization temperature and the costs associated with pollution control devices and methods.
Nonetheless, for roofing material utilized on sloped roofs, the polymerization process to date, has been required to prevent asphalt from melting and running off of a sloped roof once the melt point of non-oxidized asphalt is exceeded.
Although the oxidization process does increase the melt point of asphalt, which is required for sloped roofing materials, the oxidation process does have it drawbacks. One significant drawback of the oxidation process is that oxidation reduces the life of asphalt.
Asphalt is made up of three chemical groups, aromatics, saturates and asphaltenes. As asphalt oxidizes, its chemical composition changes. The oxidation process changes the aromatics, which are light oils, into asphaltenes, which are fine particles. Thus, oxidation makes asphalt roofing materials brittle.
Further oxidation occurs as asphalt roofing materials naturally age on a roof. This makes the roofing material even more brittle, which reduces the adhesive properties of the material so that the granules can fall off. The roofing material is also more susceptible to cracking. Asphalt that is oxidized during the manufacturing process is pre-aged, because the aromatics are driven off, thus reducing the life span of roofing material before the material is even installed on a roof.
The disclosed recycled roofing material and method of manufacturing the same overcomes many of the drawbacks associated with current roofing materials by the addition of cellulose or glass fiber to the asphalt material, which provides a material with the desired elevated melt point without requiring the oxidation process.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a recycled asphalt roofing material for use on sloped roofs, which provides the required elevated melt point of over 200° F. without using prior art methods of oxidizing the asphalt prior to its incorporation into the roofing material. This is accomplished by adding approximately 30% flux asphalt to approximately 70% reclaimed roofing materials. The approximately 30% asphalt flux reduces the viscosity of the asphalt material to a pumpable, flowable level. Although the flux is a non-oxidized asphalt with a melt point of approximately 100° F., the cellulose fiber included in the composite material modifies the asphalt in such a way as to allow raw flux asphalt to be used and still provides the desired elevated melt point. The flux also reconstitutes the asphalt since it contains the aromatic ingredients that were removed during the original oxidation process of the reclaimed roofing material and through the on-roof oxidation that occurred during the reclaimed roofing material's lifetime.
The process for manufacturing recycled fiberglass mat-based roll and shingle roofing, in its preferred embodiment, comprises impregnating a roofing material backbone, such as a fiberglass mat, with the disclosed, recycled roofing material. The impregnated mat may then be coated with an outer coat of standard asphalt coating on both sides of the recycled material. The second coating encapsulates and seals the recycled material and thus ensures that the recycled roofing material would have the same longevity as prior art asphalt roofing materials.
Recycled asphalt materials can also be used in the manufacture of other asphalt-based products, such as roofing cements, coatings and adhesives and ice and water shield products, each of which will exhibit improved performance characteristics over prior art products and will provide significant cost savings in their manufacture.
REFERENCES:
patent: 3937640 (1976-02-01), Tajima et al.
patent: 4726846 (1988-02-01), Jackson et al.
patent: 4848057 (1989-07-01), Macdonald et al.
Hawley's Condensed Chemical Dictionary, 13th Ed, Revised by Richard J. Lewis, Sr., John Wiley & Sons, Inc., pp. 96-97, 1997.
Bourque & Associates P.A.
Environmental Reprocessing Inc.
Watkins III William P.
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