Abstract: Shaped synthetic-resin bodies are made in a separable mold by injecting a flowable mass of a synthetic-resin material into the mold cavity. To precool the mass and cause an initial setting at least of the surface thereof, a liquefied gas, i.e. a low-boiling liquid which is in a gaseous state at room temperature and atmospheric pressure, is introduced between the mass and the walls of the cavity. The coolant is discharged from the cavity through at least one controllable cross-section outlet to regulate the contact time between the coolant and the mass. The initially set precooled body is ejected from the mold and is subjected to final cooling and temperature homogenization (tempering), e.g. in a liquid bath.

Abstract: Shaped synthetic-resin bodies are made in a separable mold by injecting a flowable mass of a synthetic-resin material into the mold cavity. To precool the mass and cause an initial setting at least of the surface thereof, a liquefied gas, i.e. a low-boiling liquid which is in a gaseous state at room temperature and atmospheric pressure, is introduced between the mass and the walls of the cavity. The coolant is discharged from the cavity through at least one controllable cross-section outlet to regulate the contact time between the coolant and the mass. The initially set precooled body is injected from the mold and is subjected to final cooling and temperature homogenization (tempering), e.g. in a liquid bath.

Abstract: Thermoplastic articles with highly porous cores and less porous or nonporous skins are injection-molded with the aid of a nozzle having a flow divider disposed upstream of its aprue for splitting the oncoming plastic mass into a homogeneous outer stream and an inner stream admixed with a foaming agent, the two streams merging inside the gate of a mold cavity. The foaming agent enters through a central channel which may be provided with one or more ducts alternately usable to introduce pressure fluid and coolant into the cavity lined with coalescing layers of nonfoamed and foamed plastic. The flow divider may be axially movable within the nozzle to serve as a control valve and flow regulator.

Abstract: A method of producing an excitation coil for a shaded pole electric motor comprises enclosing a coil winding element with reinforced thermoplastic synthetic material in an injection mold and supporting the coil winding element in the mold with retractable pins, the pins being retracted after partial setting of the thermoplastics synthetic material.

Abstract: Thermoplastic articles with highly porous cores and less porous or nonporous skins are injection-molded with the aid of a nozzle having a flow divider disposed upstream of its sprue for splitting the oncoming plastic mass into a homogeneous outer stream and an inner stream admixed with a foaming agent, the two streams merging inside the gate of a mold cavity. The foaming agent enters through a central channel which may be provided with one or more ducts alternately usable to introduce pressure fluid and coolant into the cavity lined with coalescing layers of nonfoamed and foamed plastic. The flow divider may be axially movable within the nozzle to serve as a control valve and flow regulator.

Abstract: An apparatus for the production of injection-molded synthetic-resin bodies having core portions and skin portions of different densities wherein a blowing agent is introduced into the core material to form macroscopic bubbles or cavities therein within the mold and under the molding conditions so that the expanding body of core material presses the skin material against the walls of the mold. The core material is injected coaxially with the skin material but under conditions such that expansion under the effect of the macropore-producing blowing agent does not occur to any significant extent until the core material is within the mold. This is a division of application Ser. No. 507,465, filed Sept. 19, 1974.

Abstract: A method of injection molding a body of synthetic resin with a smooth surface and a porous core, which comprises the steps of injecting into a mold first outer synthetic resin forming a smooth surface of the body and thereafter synthetic-resin core material containing an expanding or foaming agent. Only part of the outer material is first injected, the remainder being injected simultaneously with the synthetic-resin core material.