Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Presses or press platen structures – per se
Reexamination Certificate
2000-02-07
2001-05-08
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Presses or press platen structures, per se
C156S073500
Reexamination Certificate
active
06227275
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the field of manufacturing fabric covered panels. Particularly, this invention is related to a method for manufacturing carpet/fabric panels without the use of energy directors such as carpet engaging pins.
BACKGROUND OF THE INVENTION
Automobile car door panels typically are formed of a thermoplastic substrate that can be formed using injection molding, thermoforming, extrusion or vacuum forming. It is often desired to cover sections of this panel with another material such as a synthetic fiber carpet or a fabric or another material. This covering can be for aesthetic and/or functional purposes.
Known production processes used for bonding materials to door panels require additional consumables. These can include, but are not limited to, glue, staples, clips and other mechanical means. Such additional consumables tend to affect the re-cyclability of the thermoplastic substrates to which the carpet/fabrics are bonded.
Other known bonding processes include linear or orbital vibration welding. U.S. Pat. Nos. 5,026,445 and 5,468,335, for example, disclose a thermoplastic substrate and a synthetic fiber carpet bonded together by a vibration welder generating frictional heat at an interface between the substrate and an underlying carpet. Specifically, both U.S. Pat. Nos. 5,026,445 and 5,468,335 disclose the use of a platen having a pattern of closely spaced pins. These pins are capable of penetrating the loft of a carpet and serve as energy directors with which a backing layer of the carpet can be welded to the thermoplastic substrate at the regions opposite to the pins.
The above-mentioned patents disclose welding processes that make use of the fact that thermoplastics will remelt with the application of heat and then resolidify once the heating ceases. These processes do not require mechanical devices for the attachment of the pieces to be welded.
One of the difficulties incurred in using the above-described welding processes is that they require the carpet layer to be subjected to localized contact either with ultrasonic horns or engaging pins used in vibration welding as taught by U.S. Pat. Nos. 5,026,445 5,468,335. This localized contact, though indispensable for the disclosed processes, causes a marking or formation of telltale pin dents in the carpet welded to the plastic panel. To eliminate the dents it is then necessary to brush, comb or otherwise smooth out the effects of these processes upon the carpet surface.
Another difficulty in using the welding apparatus described in these patent is that the manufacture of platens with pins involves an expense.
SUMMARY OF THE INVENTION
With a vibration welding technique in accordance with the present invention there is no localized pin contact with the fabric and, therefore, there are no markings or pin dents to be removed or brushed out. The term fabric as used herein includes heavy fabrics such as carpets as well as lighter weight and thinner fabrics which, when used with this invention are usually backed by a thicker backing layer. The fabric may be a woven or non-woven material.
With the welding of a fabric in accordance with the invention, the fabric is virtually unaffected from a visual standpoint and no further steps need to be taken to restore the appearance of the fabric.
Instead of relying upon the use of a fixture having a specified pin structure, with the pins selected to penetrate the piles of a carpet, to produce localized contact between the fabric and the substrate, both the substrate and the fabric are transformed so as to be a part of the welding structure.
This is achieved with one method according to the invention by placing a flexible fabric consisting of a plurality of distributed high density and low density regions on a substrate so that a bottom surface of the fabric is in intimate pressurized contact with the substrate at an interface which extends over an effectively continuous and substantial portion of the bottom surface of the fabric. The high and low density regions may be an integral part of a carpet or of the backing layer attached to a fabric.
The fabric and substrate are then displaced relative to one another while in intimate pressurized surface contact until substrate zones located juxtaposed to high density fiber regions are softened to cause either an interpenetration or fusion of the high density regions with the softened substrate zones. When the displacing step is stopped the softened zones can harden and form a large number of distributed bonds between the fabric and the substrate.
The invention contemplates directly attaching the back surface of a fabric to the thermoplastic substrate even when there are no high and low density regions in the fabric. When the substrate has a textured surface with tiny raised regions the fabric can be directly vibration welded to the substrate. The substrate can have a planar surface or be contoured.
With a method of this invention various materials can be vibration welded to a thermoplastic substrate. Thus the material can be a carpet, which may have a backing layer or its backing layer can even be dispensed with. The carpet can have regions, that may not necessarily be fused with the substrate but because of their higher densities cause a melting of the underlying substrate and thus form a bond thereto by penetrating the softened zones.
The material can be a flexible fabric, which in most cases has a backing layer that can be vibration welded to the substrate without causing a destruction of the fabric due to the use of pins as taught by the above vibration welding patents. The material can be a vinyl layer with either sufficient thickness to be directly welded to the substrate or with an intermediate backing layer. The term fabric as used herein, therefore, includes such materials as a heavy fabric or carpet, vinyl with a backing layer and other similar thin materials that can be directly vibration welded to thermoplastic substrates in accordance with the invention.
When a fabric is vibration welded to a thermoplastic door panel a large selection of colors and patterns can be employed for an enhancement in the appearance of the door panel.
The invention also contemplates using a thermoplastic substrate whose outer surface is textured with a plurality of distributed tiny raised regions. Where these regions are juxtaposed to an inner surface of the fabric, bonding regions are formed at an interface between the inner surface and the substrate's outer surface. Where, these tiny raised regions on the substrate are opposite the carpet/fabric, preferential bonding regions are produced from the vibration welding and these are widely distributed so as to form distinct and extensively distributed bonded zones. The result is a well bonded fabric.
The scope of the invention includes the method for vibration or orbital welding of a carpet/fabric to a three dimensionally contoured substrate such as commonly found on car door panels and the like. Such welding involves placing the substrate and fabric between a pair of similarly three dimensionally contoured platens whose active surfaces are substantially parallel and without pins. The term vibration welding as used herein includes orbital welding.
Another feature of the invention involves the use of tooling that can be more easily prepared for a vibration welding application. Thus with tooling in accordance with the invention upper and lower tools are provide with typically the lower tool being moveable to engage the upper tool with pressure while the substrate and fabric workpieces are between them. The lower tool has a workpiece engaging surface shaped to match that of the contour of the substrate workpiece. This surface is provided with an appropriate amount of friction to grip the fabric without slipping.
The lower tool is preferably segmented with segments having surfaces adapted to conform to the contour of the back of the substrate that is to be bonded to the fabric. The segments are adjustable so as to assure appropriate surface wide pressure contact for are
Dibble Floyd H.
Soloff Robert S.
Sells James
Sonics & Mateials, Inc.
St. Onge Steward Johnston & Reens LLC
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