This invention relates to a molded carpet assembly suitable for use for example in automobiles, and to the method of producing such a carpet assembly.
The carpeting used to cover the floor areas of automobiles is conventionally molded into a nonplanar three dimensional contoured configuration which conforms to the contours of the automobile floor so as to fit properly, for example, over the transmission hump on the floor of the automobile. In order to make the carpeting moldable and shape sustaining, it is conventionally provided with a backing or coating of a thermoplastic polymer composition. The thermoplastic polymer backing may contain substantial amounts of inorganic fillers to improve the sound deadening properties. Additionally, the automotive carpets are normally provided with padding on the rear surface for cushioning, sound deadening, and thermal insulation. The pads are commonly formed from relatively inexpensive fibers such as jute or recycled waste fibers, and they are precut into predetermined desired shapes and bonded to the back-coated surface of the molded carpet. Formerly, the padding was used over the entire rear surface of the carpet, as shown for example in Squier U.S. Pat. No. 3,673,034. More recently, in an effort to reduce weight and cost and to achieve better conformity to the irregular contours of the automobile interiors, the pads have been applied only in selected areas of the carpet where the cushioning, sound deadening and thermal insulation are most needed. Depending upon the particular automobile body style, the molded carpet may require one or several pads, often of varying thickness, at different locations on the back of the molded carpet.
In the production of this type of molded carpet assembly, a number of difficulties are encountered. The pads often vary in size and thickness, which results in nonuniformity of the resulting product. This construction requires manual placement and assembly of the pads which, in addition to the labor costs involved, often results in variations in placement of the pads on the carpet backing, which further contributes to a nonuniform product and results in a poor fit when the carpet assembly is later installed in the automobile. Difficulties are also encountered in obtaining good adherence between the fiber waste pads and the carpet backing. As a result, the pads may have a tendency to become detached during subsequent handling or installation.
It has also been proposed to employ a foam cushioning layer instead of fiber pads in moldable automobile carpet structures. Moldable composite carpet structures of this type are disclosed, for example, in U.S. Pat. Nos. 4,016,318; 4,078,100; 4,186,230; 4,230,755; and German OS No. 29 24 197. Typically, they contain both a foam layer and a moldable thermoplastic polymer layer on the back of the carpet. The presence of the foam layer makes molding of the carpet difficult, since the thermal insulating property of the foam interferes with the necessary heating and cooling of the moldable thermoplastic layer during the molding operation. Also, excessive heating may damage the foam layer. In these constructions, the foam pad extends over the entire rear surface of the carpet assembly, and no provision is made for providing the pads in selected areas only of the carpet or for variations in pad thickness, as is needed for many automotive body styles as noted earlier. The presence of the foam pad throughout the rear surface also restricts the shapes and contours which can be imparted to the carpet by molding.
With the foregoing in mind, it is an object of the present invention to overcome the disadvantages associated with the existing known methods of production of a molded automotive carpet assembly.