Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles – Stratified or layered articles
Reexamination Certificate
1999-02-26
2001-04-24
Theisen, Mary Lynn (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
Stratified or layered articles
C264S112000, C264S122000, C264S911000
Reexamination Certificate
active
06221291
ABSTRACT:
TECHNICAL FIELD
The invention relates to a method of forming a preform using waste plastic material.
BACKGROUND ART
A prior method of forming a plastic preform includes extruding virgin resin to form a flat plastic sheet, and die-cutting the plastic sheet to form the preform. Because the preform is made entirely of virgin resin, the preform is relatively costly to manufacture. Furthermore, because the plastic sheet is die-cut to obtain the desired shape of the preform, there is significant excess or scrap material associated with this method. The preform must also be heated prior to and/or during a subsequent molding operation.
Another method of forming a preform includes die-cutting layers of fibrous material from rectangular blanks or continuous rolls of material. The fibrous layers, which may include synthetic fibers and/or natural fibers impregnated with resin, are then heated and compressed together to form the preform. Because the fibrous layers are die-cut to obtain a desired shape, this method also involves significant excess or scrap material.
U.S. Pat. No. 5,807,513 discloses a method of recycling used trim components to form new trim panels for use in motor vehicles. The method includes shredding manufacturing scrap and post-consumer scrap into small particles to produce fluff. The fluff is then mixed with water and a binder reagent, and the mixture is placed in a sheet mold where it is formed into a pre-peg sheet. Finally, the pre-peg sheet is compression molded to form a finished trim panel. Similar to the above methods, however, the pre-peg sheets must typically be cut or otherwise trimmed prior to and/or after the compression molding step.
DISCLOSURE OF INVENTION
The present invention overcomes the shortcomings of the prior art by providing a method of forming a preform that involves positioning waste plastic material within an unconsolidated blank that has an outline corresponding to a desired outline of the preform. Consequently, this method reduces excess or scrap materials as compared with prior art methods. Furthermore, because the preform comprises waste plastic material, it is less costly to manufacture than preforms made only of virgin resin.
It is therefore an object of the invention to provide a method of forming a preform using waste plastic material. Such waste plastic material may include post consumer waste plastics, manufacturing operation wastes or post industrial waste plastics, plastics separated from automotive shredder residue, or any combination of these materials.
Under the invention, a method of forming a preform, for use in manufacturing a part having a part outline, includes positioning waste plastic material within an unconsolidated blank, the unconsolidated blank having an outline corresponding to a desired outline of the preform and the part outline; selectively positioning reinforcing material within the unconsolidated blank for added strength; heating the unconsolidated blank; and compressing the unconsolidated blank to form the preform.
According to one aspect of the invention, selectively positioning reinforcing material within the blank includes selectively depositing virgin resin at discrete locations within the blank. In this way, virgin resin can be selectively deposited in areas of the preform that require additional strength and/or that cannot tolerate inconsistencies in raw material.
According to another aspect of the invention, selectively positioning reinforcing material within the blank includes selectively positioning reinforcing fibers within the blank.
Under the invention, a method of forming a part having a part outline includes providing a frame that defines a first retaining region; positioning a form proximate the frame such that a portion of the form extends into the first retaining region, the portion of the form defining a second retaining region within the first retaining region; selectively depositing virgin resin within the second retaining region; removing the form from the first retaining region; depositing waste plastic material within the first retaining region with the virgin resin to form an unconsolidated blank; heating the blank; and compressing the blank.
Preferably, the step of compressing the blank comprises compressing the blank to form a consolidated preform. Furthermore, the first retaining region preferably has an outline corresponding to a desired outline of the preform and the part outline, so as to reduce scrap materials associated with forming the preform.
Additionally, under the invention, a method of forming a preform, for use in manufacturing a part having a part outline, includes positioning a first reinforcing layer proximate a first surface; selectively depositing waste plastic material on the first reinforcing layer so as to form a waste plastic material layer having an outline that corresponds to a desired outline of the preform and the part outline; positioning a second reinforcing layer on the waste plastic material layer; heating the reinforcing layers and the waste plastic material layer; and compressing the reinforcing layers and the waste plastic material layer.
These and other objects, features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4525321 (1985-06-01), Tönniges
patent: 5041260 (1991-08-01), Johnson et al.
patent: 5217672 (1993-06-01), Kelman et al.
patent: 5229052 (1993-07-01), Billiu
patent: 5503788 (1996-04-01), Lazareck et al.
patent: 5575965 (1996-11-01), Caronia et al.
patent: 5807513 (1998-09-01), Gebreselassie
patent: 5843365 (1998-12-01), Pinson et al.
patent: 42 15 349 A1 (1993-11-01), None
patent: 0 443 051 A1 (1991-08-01), None
patent: 0 566 830 A1 (1992-02-01), None
patent: 0 638 404 A1 (1993-07-01), None
patent: 5-111917 (1993-05-01), None
patent: 6-079836 (1994-03-01), None
patent: WO 98/30371 (1998-07-01), None
English Abstract for EP 0 433 051 A1.
English Abstract for EP 0 566 830 A1.
English Abstract for DE 42 15 349 A1.
LaPorte Gregory A.
Liu Xianping
Slaven John P.
Van Ert Jack M.
Witt, Jr. John F.
Brooks & Kushman P.C.
Lear Corporation
Theisen Mary Lynn
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