This invention provides process and apparatus for the injection molding of epoxy resin molding compositions. The constituent materials of the epoxy resin feed mixture are separated into at least two groups in at least two separate chambers. Each of the chambers is subjected to a vacuum of from about 50 to 100 Torr in order to degassify the feed material and thereby avoid the formation of voids in the final molded product. The degassified molding materials are then fed under pressure to a mixing tube which may be heated. The mixing tube is connected by means of a valve having a discharge orifice alignable with the entry passage of a mold. The mixing tube, valve and orifice are movable toward the mold so that the orifice engages the mold and is maintained in engagement therewith at a greater pressure than the pressure exerted on the molding composition fed to the mixing tube and mold.

Plant for injection molding of thermosetting epoxy plastics

Glass fibers are coated with uncured thermosetting resin selected from the group consisting of glycerol triacrylate, ureaformaldehyde and phenol-formaldehyde of the type designated as B stage. About 5 percent by weight of the coated fibers, while cool, are introduced into a mixture of gas and molten thermoplastic material selected from the group consisting of polypropylene nylon and polystyene shortly (i.e. less than a minute) prior to entry into the mold of low pressure injection molding apparatus. The heat of the molten thermoplastic material brings about a curing of the thermosetting coating on the glass fibers, but such curing is so slow that it becomes effective at about the same time as the thermoplastic material cools and solidifies in the mold. The product, a thermoplastic structural foam having short fibers of thermoset-coated glass fibers distributed throughout, has greater stiffness and greater tensile strength than conventional structural foam.

Glass fiber reinforced thermoplastic cellular plastics

An injection molding apparatus includes a nozzle which is directly connected to a mold for injecting a molding material into the mold. The mold defines at least one cavity in the shape of a element to be molded and at least one gate passage, each gate passage interconnecting a separate cavity with the nozzle. The shape of the gate passage permits a rapid curing of any residual molding material, and permits separation of the mold and the nozzle before the molding material in each cavity is cured. The nozzle is then used for a subsequent procedure or molding process while the molding material in the cavity cures. The nozzle defines a first bore and a second bore arranged longitudinally in sequence, and a side hole for introducing the molding material into the first bore. The nozzle includes a first plunger which is selectively reciprocally movable in the first bore, and a second plunger which is selectively reciprocally movable in the second bore and in a central bore defined in the first plunger. To charge a mold, the first plunger is moved to expose the side hole and control the flow of molding material into the second bore while the second plunger is extended into the second bore. The second plunger is raised to permit the first plunger to inject the molding material into each cavity via the second bore and each gate passage. The second plunger is then extended to purge any residue molding material from the nozzle.

Apparatus for the injection molding of semiconductor elements

A fully temperature controlled apparatus comprising a thermoplstic stage assembly having solid processing components (100) and a finshing stage assembly having liquid processing components (120) and liquid applicator components (130) or finishing assembly.

Apparatus for applying chemical coatings

A method of anti-fouling a metal structure disposed in water, the method comprising providing a clean surface on the metal structure, applying a tie coat (204) to the surface (206), and applying a thermoplastic top coat (202) to the tie coat (204).

Method for applying chemical coatings

METHOD AND APPARATUS FOR PREPARING FOR AND DIRECTING A MIXTURE OF PLASTIC MATERIAL AND FILLER MATERIAL INTO MOLDING DIES TO FORM AND ARTICLE OF MANUFACTURE. PREPARATION INCLUDES THE MELTING OF A THERMOPLASTIC MATERIAL IN A HEATED RECEPTACLE AND CONTINUOUSLY CIRCULATING THE MELTED PLASTIC THROUGH AND THE RECEPTACLE WITH TEMPERATURE CONTROL. A TRANSFER VALVE MAY BE OPERATED TO DIVERT THE CIRCULATING PLASTIC MATERIAL TO A HEATED MIXING RECEPTACLE WHERE FILLER MATERIAL IS ADDED, THE TEMPERATURE BEING CONTROLLED TO ASSURE COMPLETE WETTING AND MIXING OF THE FILLER MATERIAL BY AND WITH THE LIQUID PLASTIC. CONTINUOUS CIRCULATION THROUGH THE MIXING RECEPTACLE MAINTAINS THE FILLER MATERIAL IN MECHANICAL SUSPENSION IN THE MIXTURE. A SECOND TRANSFER VALVE MAY BE OPERATED TO DIVERT THE MIXTURE INTO A HEATED HOLDING RECEPTACLE FOR CONTINUOUS CIRCULATION THERETHROUGH AND, AS NEEDED, FOR CONVEYANCE TO MOLDING DIES. SUITABLE VALVE MEANS ARE PROVIDED TO DIVERT FLOW TO THE DIES THROUGH AN INJECTION GUN. UPON FILLING HE DIES, A MULTIPLE CYLINDERED INJECTION MACHINE PRESSURIZES THE MIXTURE THROUGH THE GUN TO ELIMINATE VOILDS IN THE MOLDED ARTICLE AND TO COMPENSATE FOR SHRINKAGE AS THE MIXTURE COOLS.

Alexander Mcinnis Stirling

Papers

Plastic mixing and injection system

Verfahren und Vorrichtung zum Formen