Resin and fiber compounding process for molding operations
View Patent ↗Molding material consisting of resin coated reinforcing fibers in a molten mass of resin and fibers is prepared at a molding site for controlled supply to a molding machine. A conveying device, such as a pair of pinch rollers, serves to pull fibers from supply spools through guide orifices of a coating die having a chamber within which the fiber is coated with molten resin. Further impregnation of the fibers with resin takes place in the conveying device, which also develops pressure on its output side serving to push the mass of hot resin and fiber into a receiving device for movement to a molding machine. The receiving device may be the feed screw for an injection molding machine or simply a plate movable to and from a compression molding machine. The fibers may be cut into predetermined lengths by a cutting device positioned downstream of the aforesaid conveying device.
1. A process for preparing fiber-reinforced resin for use in molding machines comprising:
threading at least one fiber strand through a chamber; and
intermittently introducing into the chamber thermoplastic resin in a molten state, and thereby coating the fiber strand with thermoplastic resin;
pushing the resin coated fiber strand in a heated state into a barrel housing a rotatable screw simultaneously with the introduction of thermoplastic resin into the chamber and independently of the action of the screw;
wherein the fiber strand is cut into predetermined lengths after being coated and prior to being directed into a barrel housing a rotatable screw.
2. The process of claim 1 , wherein
the rotatable screw is a feed screw of an injection-molding machine.
3. The process of claim 1 , for use in a compression molding machine.
4. The process of claim 2 , wherein
the fibers are cut by the feed screw inside of the barrel.
5. The process of claim 1 , wherein
the barrel rotatable and screw include a compounding extruder in which the fiber and resin are thoroughly mixed into a molten mass.
6. The process of claim 5 , further including
shaping the molten mass from the compounding extruder into a compressible shape and thereafter conveying the shaped mass to a molding machine adjacent to the compounding extruder.
7. The process of claim 6 wherein the molding machine is a compression-molding machine.
8. The process of claim 6 wherein said molding machine is a transfer-molding machine.
9. The process of claim 1 , wherein the rotatable screw is the feed screw of a profile-extruding machine.
10. A process for preparing fiber-reinforced resin for use in molding machines comprising:
passing a fiber strand through a chamber;
intermittently introducing into the chamber a thermoplastic resin in a molten state, and thereby coating the fiber strand with thermoplastic resin; and
pushing the resin coated fiber strand in a heated state into a fluidic conveying mechanism in conjunction with the introduction of thermoplastic resin into the chamber and independently of the action of the fluidic conveying mechanism;
wherein the fiber strand is cut into predetermined lengths after being coated and prior to being directed into the fluidic conveying mechanism.