Relatively inexpensive thermoformable mat of reduced density and rigid laminate which incorporates the same

Abstract

A relatively inexpensive mat is provided which through the application of heat and pressure readily can be densified to form rigid shaped articles having a reduced overall density. The mat is substantially free of a binder (e.g., a latex binder) and consists essentially of a substantially radom array of (a) relatively coarse cellulosic fibers, (b) thermoplastic synthetic polymer fibrils, (c) non-fibrous thermoplastic synthetic polymer particles, (d) substantially void-free substantially water-insoluble particulate inorganic material (e.g., talc), and (e) particulate void-containing substantially water-insoluble inorganic material (e.g., expanded volcanic glass) having a lesser density than component (d) in the specified quantities. A plurality of the mats while stacked together with similar mats of greater density on at least the upper and lower surfaces may be subjected to heat and pressure to accomplish densification and thermal bonding within and between adjoining mats to form a laminate. The presence of component (e) in conjunction with the other components has been found to enable the efficient control of the density in the resulting product regardless of the pressure applied during thermoforming. The resulting cellulosic fiber reinforced product can be used to advantage as a shaped rigid lightweight panel for use as an inner automobile door liner or in similar end uses which require a rigid sheet or panel having a predetermined configuration. A decorative surface optionally may be applied to the resulting article.

Dependencies are inferred from the claim text.