Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Patent
1997-03-07
1999-11-02
Stemmer, Daniel
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
2940209, 428 63, B29C 7302
Patent
active
059762918
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a process for joining plastic moldings using a one-component or two-component adhesive, the connecting joint being spanned by metal strips and the metal strips being at least partly embedded in the adhesive layer. More particularly, the invention relates to a process for repairing damaged plastic moldings.
BACKGROUND OF THE INVENTION
In several branches of industry, above all in the automotive industry, metal moldings are being increasingly replaced by plastic moldings. Plastic moldings are used on the one hand to save waste and on the other hand to simplify production cycles. In the automotive industry, for example, tailgates of automobiles, wing sections and, in particular, fenders of plastic moldings are being used to increasing extent. These plastic moldings may consist of a number of different plastics or composites, including for example polyethylene, polypropylene, polycarbonate, acrylonitrile/butadiene/styrene terpolymers (ABS), polyamide, polyurethane, polyepoxides and polyesters (particularly in the form of sheet molding compounds (SMC) or bulk molding compounds (BMC)). In addition, so-called polymer blends, for example EPDM-modified polyethylenes and polypropylene materials, are often used.
These plastic moldings can be damaged in the operation of the machines, apparatus and, in particular, vehicles (automobiles) equipped with them. In particular, the fenders of automobiles are often damaged in wrecks.
Hitherto, the damaged moldings have generally been replaced by new parts and not repaired.
This approach has two major disadvantages so far as the consumer is concerned. On the one hand, it is far more expensive to replace the damaged plastic molding by a new part than to repair it by simple methods. On the other hand, the damaged plastic molding has to be disposed of. This hitherto necessary disposal of bulky and unwieldy parts is highly undesirable on environmental grounds, in addition to which the disposal costs contribute significantly towards increasing the repair costs.
Accordingly, there has been no shortage of attempts to develop processes for repairing damaged plastic moldings although they have all been found in practice to show serious disadvantages.
EP-A-186081 proposes using metal plates coated with hotmelt adhesives based on thermoplastic copolymers for bodywork repairs. The plates thus coated are then bonded over the damaged area. However, this process can only be used for metal parts and not for plastic moldings because, in this case, the area to be repaired has to be preheated to temperatures at which the hotmelt adhesive based on thermoplastic block copolymers softens, i.e. it has to be heated to temperatures above 100.degree. C. Many plastic moldings, particularly those based on thermoplastic materials, lose their dimensional stability and their mechanical properties at temperatures as high as these, so that the process proposed in EP-A-186081 is not suitable for repairing plastic moldings.
EP-A-315101 describes a method for repairing damaged articles of composite materials. According to this document, the damaged area of the composite material is mended by bonding metal or pieces of cured composite material to the surface surrounding the damaged area. The adhesive used is a rubber-modified vinyl ester resin composition. In another embodiment, an uncured reinforcing material is impregnated with a rubber-modified vinyl ester resin composition, placed over the prepared damaged zone and cured there. Graphite fiber cloths and glass fiber cloths are proposed as the reinforcing material. According to EP-A-315101, the metal or composite material is applied to the entire damaged area. There is nothing to indicate whether this repair process is also suitable for repairing plastic moldings of thermoplastic materials.
The damaged areas of plastic moldings, particularly fenders of automobiles, very often develop relatively long cracks which drastically reduce the mechanical strength of the molding. Efforts to repair such damage in the con
REFERENCES:
patent: 3700517 (1972-10-01), Roach
patent: 4707391 (1987-11-01), Hoffmann
patent: 4732633 (1988-03-01), Pokorny
patent: 4743468 (1988-05-01), Jiminez
patent: 5298099 (1994-03-01), Hoffmann
patent: 5653835 (1997-08-01), Glen
Webster's II New Riverside Dictionary, Houghton-Mifflin Co., (1984).
Henkel Teroson GmbH
Jaeschke Wayne C.
Meder Martin G.
Stemmer Daniel
Szoke Ernest G.
LandOfFree
Process for joining plastic moldings does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for joining plastic moldings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for joining plastic moldings will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2129789