Method of injection-molding and cooling of shaped synthetic-resin bodies
OwnerRobert Hanninginventor
Life of this patent
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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.
Claims7
A process for making a shaped body of synthetic-resin material in a mold cavity formed by separable mold parts, said method comprising the steps of:
- injecting a mass of said synthetic-resin material into said mold cavity in a plastically deformable heated state to fill said mold cavity;
- immediately upon filling said mold cavity, introducing a liquefied-gas coolant between the synthetic resin in the mold cavity and the walls of said mold cavity;
- conducting said coolant along surfaces of the synthetic resin in said mold cavity to substantially uniformly distribute said coolant along said surfaces with a controllable contact time therewith;
- discharging coolant upon the flowing thereof in contact with said surfaces from at least one opening formed in the mold;
- and
- opening said mold to eject a molded body formed from said synthetic resin from said mold cavity upon the contact of said coolant therewith.
Dependencies are inferred from the claim text.