Patent Document

BACKGROUND OF THE INVENTION 
     This invention relates to a method of recycling. More specifically, this invention relates to a method of recycling fiberglass reinforced plastics. 
     Fiberglass reinforced plastics (FRP) are a class of composite building material consisting of a fibrous reinforcement sheathed in a polymer matrix. The polymer matrix is applied as a liquid resin and chemically cures as a solid when an initiator is introduced. Reinforcing materials such as fiberglass, carbon, and Kevlar are often used as the reinforcing material in these types of composites. In this example, a polyester resin is used as the matrix and fiberglass is used as the reinforcing material. 
     Manufactures make FRP service truck bodies and truck caps for service and utility industries. When manufactured the fiberglass reinforced plastics process uses an open mold spray up process where glass and catalyzed resin are applied onto a mold surface. During this process a large quantity of solid waste is generated which currently must be disposed within a landfill. There are three primary types of waste generated which include overspray waste, trim waste, and grinding/cutout waste. Overspray waste is the glass and resin that misses the mold and hits the floor during operation. Trim waste is FRP trimmed off the edges of the product and the open mold. Grinding/cutout waste consists of solid FRP laminate cut out or ground away from a product to make openings for doors, wheel wells, and trim. 
     Thus, it is a principal object of the present to provide a method of recycling to make useful products out of fiberglass reinforced plastic waste material. 
     These and other objects, features, or advantages will become apparent from the specification and claims. 
     BRIEF SUMMARY OF THE INVENTION 
     A method for recycling fiberglass reinforced plastics for reusing in FRP truck bodies. The steps include grinding the fiber reinforced plastic materials with a grinder into a predetermined length to form a ground material. This ground material is then mixed with constituents to form a blend. This blend is then poured into a mold and compressed to form a panel. The panel is then used for a plurality of applications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side plan view with hidden lines of a grinder; 
         FIG. 2  is a side plan view of a mixing device and mold for recycling fiberglass material; and 
         FIG. 3  is a side plan view of a pneumatic press; 
         FIG. 4  is sectional view of a recycled panel. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In order to perform the method of recycling fiberglass reinforced plastic scraps  10  a grinder  12  is used as shown in  FIG. 1 . The grinder  12  comprises a housing  18  with throat opening  20  that receives fiberglass reinforced plastics scraps  10  within a mulching compartment  22 . Within the compartment  22  are a plurality of knives  24  with carbonite corners  26  to grind and mulch the fiberglass reinforced plastics. The plastic scraps  10  or materials are crushed and sliced by the knives  24  and a screen  28  is used to filter out the grounded scrap into a predetermined length. A built-in fan  30  within the grinder  12  helps control the temperature within the grinder  12  to virtually eliminate any risk of spontaneous combustion. 
     The ground scrap or material is then mixed with other constituents to achieve a proper blend. In a preferred embodiment the ground material is ¾. The constituents include but are not limited to a fixed amount of polyester resin, titanium dioxide that achieves a white pigment on the end product, thermoplastic micro spheres, and a catalyst that only initiates cure when heat activated such as Benzoyl Peroxide (BPO). When polyester resin and BPO are both used as constituents the polyester resin used is not promoted for BPO so the curing reaction only takes place when a predetermined elevated temperature is reached. Once this predetermined temperature is reached the reaction occurs rapidly. 
     In a preferred embodiment the blend is comprised of 35-40% ground FRP, 60-65% resin and 1% thermosplastic micro spheres. The pigment and catalyst are adjusted as required by the blend. The mixing is done with a mixing device  32 . In one embodiment the mixing is done by hand using mixing devices in the form of drills with mixing blades or alternatively could be mixed in a batch process in a mixing device such as a cement or bakery mixer. 
     After the blend has been sufficiently mixed, the blend is poured into a mold  34  that comprises a predetermined shape depending upon the desired application. Design considerations such as beveled edges or surface graphics can be built right into the mold  34 . In a preferred embodiment, panels are made which serve a number of purposes. 
     When making panels  35  in a preferred embodiment, after the blend is poured into the mold  34 , the blend is leveled out so that the top of the blend is parallel with the top of the mold  34 . A smooth flat insert  36  is then placed over the poured blend in the mold  34  to get two flat sides. Preferably, an air operated press  38  ( FIG. 3 ) provides the compression needed to make the resin flow throughout the mold  34  and achieve two flat sides without air voids. The platforms or platens  40  of the press  38  are electrically heated in order to cure the blend with the specific catalyst chosen. In a preferred embodiment, the thickest panel  35  made would be ⅜ thick. Therefore the mold depth would be ⅜ plus the volume displaced by the compression forces of the press  38 . Mold stops  42  are used control the thicknesses of the panels. 
     After cure, the mold  34  is taken out of the press  38 . The next mold  34  is placed in the press  38  to undergo the same process. During this time the part is pulled from the mold  34 , the mold  34  is cleaned and the blend is poured into a second mold. At least three mold sets are needed to achieve the proper efficiency; one under compression, one being mixed and one being pulled and cleaned. The resulting panels have the appearance of white granite countertop. 
     The panels  35  are used in a variety of applications. Specifically the panels  35  can be used for reinforced coring of service and utility bodies, bulkheads in service and utility bodies, shelving sheets, shelving dividers, tailboards, and boxes. The benefits of these recycled panels include an aesthetically pleasing appearance, lighter weight, increased strength, and overall lower costs. The recycled panels were independently tested against 7/16 OSB wood coring panels. The test results showed a 40% increase in tensile strength, a 27% increase in flexural strength, and a 90% increase in shear strength as compared to the OSB wood coring panels. Thus, disclosed is a recycling method that provides a method of reusing fiberglass reinforced plastics that provides paneling that is of improved strength and appearance over previous panels used in the industry. Thus, at the very least all of the stated objectives have been met. 
     It will be appreciated by those skilled in the art that other various modifications could be made to the device without the parting from the spirit in scope of this invention. All such modifications and changes fall within the scope of the claims and are intended to be covered thereby.

Technology Category: 4