Alliedsignal Inc.

Allied Corporation

Radcliffe W Farley

Clarke A Rodman

Edward C Homonoff

Edward A Vaughn

Ian C Twilley

Method for manufacturing a molded article, for use, for example as a fluid filter or as a preform for a structural composite, is prepared from a batt of nonwoven structural fibers and a binder material, such as binder fibers or a thermoresponsive resin. The batt is stabilized by exposing it to a temperature slightly below the melting point of the binder material, so that the binder material becomes tacky and bonds the fiber materials at the surface of the batt. By exposing the batt to the heat for only a few seconds, only the binder material at the surface of the batt bonds the structural fibers; the structural fibers within the batt remain unbonded. Accordingly, the batt is 'skinned', so that it is stiff enough to be handled, but is still flexible enough that it can be molded into complex shapes. The molding is effected in a mold in which heated air is drawn through the batt to force it to assume the contours of the mold.

Method of manufacturing molded articles

A molded article, for example, a filter or a preform used in the manufacture of fiber-reinforced composites, is manufactured from an air laid batt from a single fiber type or a mixture of fibers. The batt is either resinated with a thermoplastic material or includes a thermoplastic binder fiber. The batt is formed into the desired shape of the molded article in a through-air mold and heated sufficiently to set the thermoplastic material, so that the resulting article retains the desired shape. If the article is to be used as a fluid filter, it can be used either as it is removed from the mold if a filter of uniform density is desired, of the article can be further processed in a compression mold to densify portions of the article to thereby form, for example, a fluid impervious portion used as a gasket. If the article is to be used as a preform for a structural composite, it is then to be transferred to a resin injection mold.

Method of manufacture of formed article

Fibers or other bulk material to be conveyed into an air forming system are fed in a continuous stream at a uniform rate to the air forming system by conveying the material into an elongated weight pan, weighing the pan, dropping the material onto a conveyor, and adjusting the speed of the conveyor to compensate for variations in weight. After a target weight in the pan is achieved, material is no longer fed into the pan, but the pan is not dumped until the conveyor has moved at least a distance equal to the length of the pan. The conveyor is at least twice as long as the pan, so that two dumps of the pan can be accommodated on the belt at the same time, thereby permitting the speed of the belt to be adjusted to feed the material into the air forming system at a substantially constant rate.

Method and apparatus for metering material into an air forming system

A fiber reinforced, composite article is manufactured by forming a nonwoven, air-laid batt from a single fiber type or a mixture of fibers. The batt is either resinated with a thermoplastic material or includes a thermoplastic binder fiber. The batt is formed into a preform having the desired shape in a through-air mold and heated sufficiently to set the thermoplastic material, so that the resulting preform retains the desired shape and is sufficiently stiff to withstand the pressure of the injected resin. The preform is then transferred to a resin injection mold, where the interstices between the fibers are saturated with an appropriate resin matrix. As the fibers of the preform are saturated (or after a saturation but before the resin sets) the resin transfer mold is compressed, thereby forming the preform into its final desired thickness and increasing the concentration of the fibers to give the preform appropriate strength. Accordingly, the preform retains the open characteristics permitting easy injection of the resin, while later being compressed to increase the concentration of the reinforcing fibers to give the resulting composite the appropriate strength.

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Worcester, PA, United States of America

Radcliffe W Farley