Method allowing the incorporation of a metallic structure into a

Details Method allowing the incorporation of a metallic structure into a Method allowing the incorporation of a metallic structure into a

1993-12-15

1996-01-30

Raimund, Christopher W.

Adhesive bonding and miscellaneous chemical manufacture

Methods

Surface bonding and/or assembly therefor

156166, 1563099, B32B 3100

Patent

active

054878047

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The present invention relates to an improved method allowing the incorporation of a metallic structure into a plastic with a view to producing molded articles; it also relates to a novel type of metallic structure particularly suited for the implementation of such a method as well as the molded articles including such a structure, and which have the characteristic of reflecting or barring electromagnetic waves and/or of being a good conductor of static electricity.
In the rest of the description, the term "plastic" will be used in the wide sense so as to designate any type of material such as, for example: styrene-based materials (ABS, polystyrene, ASA, SAN), polyamides, thermoplastic polyesters (PET, PBT), polycarbonates, PMMAs (polymethyl methacrylate), PVC, etc., as well as the mixtures of these various materials (blends) polyurethanes, phenolics, etc., thermoplastic elastomers (styrene-based, polyolefin-based, polyurethane-based or other thermoplastic elastomers) etc., which can be shaped by any type of process, such as, for example, injection molding, thermoforming, extrusion blow-molding, rotomolding, or other processes.
It is well known that, during the production by molding of articles based on plastics, it is possible to incorporate therein various additives and/or reinforcements, and this is done in order to confer on them specific properties.
Thus, in order to confer on them properties ensuring electromagnetic (EMI) or electrostatic (ESD) protection, it was proposed a long time ago to incorporate into such plastics various fillers, such as metal powders. However, such a procedure has very many drawbacks, among which it is possible to cite the difficulties of having a very homogeneous composition.
One solution to solve this problem consists in covering the molded part with a reflective surface layer, which solution is especially used for producing reflective assemblies (antennas, for example). However, such a surface coating has the drawback of being subjected to external attack, and therefore may deteriorate over time. Moreover, such techniques require for their implementation complex and expensive equipment and processes.
In order to overcome these drawbacks, it was proposed, and this emerges especially from U.S. Pat. No. 4,242,686, to incorporate into the molded article, especially during its production, an intermeshed metallic structure. Although this solution enables shaped articles to be obtained in which the conducting or reflective element is perfectly protected from external attack, it does not, however, produce assemblies of complex shape and/or of small thickness taking into account the fact that the metallic structure is in the shape of a tubular sleeve which lacks pliability, and which, during its implementation, is flattened when it is impregnated with the plastic resin. Moreover, it clearly emerges from this document that the incorporation can only be envisaged solely for the production of articles of the "laminated" type, in which the material is produced by successive layers and not for being implemented according to similar techniques of composite forming or overmolding.
It has also been proposed, in EP-A-0,243,193, to produce conductive sheets or films, optionally shaped by making use of a textile structure (woven or knitted fabric), constituted by a twisted composite yarn which includes conductive fibers and thermoplastic fibers which have a hot shrinkage greater than that of the said conductive fibers. Such a yarn has the characteristic that, during a heat treatment, a shrinkage of the thermoplastic fibers occurs in the axial direction, which makes the conductive fibers become spiralled around the said thermoplastic fibers.
However, such a solution has drawbacks, amongst which it is possible to cite: meshwork, lower conductivity because of lack of contact.
In many applications (for example, for the production of molded protective caps for computer equipment), metal, especially stainless steel, assemblies are still used which have the drawbacks of

REFERENCES:
patent: 4381421 (1983-04-01), Coats et al.
patent: 4863789 (1989-09-01), Arai

Affiliated with

Also associated with

Rating

Method allowing the incorporation of a metallic structure into a does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method allowing the incorporation of a metallic structure into a, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method allowing the incorporation of a metallic structure into a will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-155216