Laminated structures with multiple denier polyester core fibers, randomly oriented reinforcement fibers, and methods of manufacture

Abstract

A laminated panel-type structure particularly suited for vehicle interior applications such as headliners and door panels has a multiple denier polyester fiber core and randomly oriented structural reinforcing fibers. The laminated structure has superior sound attenuation properties resulting from a core of intertwined polyester fibers of differing deniers, with preferably relatively larger denier fibers on exterior areas of the core and some bicomponent fibers, short non-woven reinforcing fiber strands which are randomly attached and intertwined with the core on opposing major sides of the core, an impervious polymer film with a low melt layer which retains the reinforcing fibers against one side of the core and is attached to a scrim layer, and a polymer web on an opposite side of the core which retains the reinforcing fiber strands on the opposing major side of the core and to which a cover stock is applied. The invention further includes a method of manufacturing the laminated structure wherein the various layers are sequentially unfurled from spools, passed through nip rollers at points of various subcombinations of materials and layers, the reinforcing fiber strands are randomly distributed on to the carrying layers from hoppers or directly from a fiber chopping device, and the completed laminated structure is cut and molded.

Description

1. The present invention pertains generally to molding of composite materials including fibers and plastics and, more particularly, to molding of structural and acoustical panels which include glass fibers and thermosetting resins.2. Composite material panels-are used in many different applications, including automobiles, airplanes, housing and building construction. The properties sought in such panels are strength, rigidity, sound absorption, and heat and moisture resistance. One application of such panels which has been especially challenging is automobile headliners and other automotive interior panels. Many different types of laminates and laminated composites have been tested and produced for use in automobiles. Some headliners have a core of fiberglass fibers and a polyester resin. Others have been manufactured from a core of open cell polyurethane foam impregnated with a thermosetting resin, and with a reinforcing layer of fiberglass. This type of construction is inefficient...

AI Technical Summary

Benefits of technology

7. In accordance with another aspect of the invention, there is provided a laminate structure with enhanced sound absorption and structural properties having a central core having opposite sides and made of a combination of intertwined polyester fibers having differing deniers in an approximate range of 0.1 to 100, the combined fibers arranged with the core to form a layer of fibers of relatively small denier adjacent to a layer of fibers of relatively large denier, a resin applied to the core, structural fibers randomly attached to the opposite sides of the core by contact with the resin, at least some of the structural fibers being intertwined with the polyester fibers of the core, a low melt polymer web over the structural fibers on one of the opposite sides of the core, and a face cloth over the low melt polymer web, an impervious polymer film over the structural fibers on an opposite side of the core, and a scrim layer over the impervious polymer film.

Problems solved by technology

One application of such panels which has been especially challenging is automobile headliners and other automotive interior panels.

This type of construction is inefficient in mass production, and has low acoustical attenuation which is particularly undesirable for automobile headliners.

However, fine denier fibers in the range of 1.2 or less lack the resiliency required for retention of thermoformed shapes.

Although resiliency can be achieved by impregnating the fibers with a resin, it is very difficult to impart an even distribution of resin into a fibrous batt containing fine denier fibers.

Hence, given these trade-offs, a truly superior acoustical dampening headliner of sufficient strength could not be produced.

5. Although layers containing fiberglass have the desirable characteristics of strength and some sound attenuation, they have the undesirable traits of reflecting sound when made very hard or dense.

Fiberglass, particularly in woven mat form, is also difficult to handle and is a known skin irritant.

Because the production of headliners and similar panels using fiberglass is most commonly done manually, this is a significant problem which has not been addressed.

Alternative fibers, natural and synthetic, have not been developed to be both cost effective and have strength comparable to glass.

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