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Leonard B Ryder

Wolf R Vieth

A technique is described for preparing molecular biaxially oriented hollow articles from thermoplastic materials. The invention involves forming a parison on a cooled core rod by injecting a hot thermoplastic material into a cavity formed by the core rod and a cooled injection mold, cooling the parison with low temperature coolant to a temperature within the orientation range of the thermoplastic material, transferring the parison to a stretch blow molding position and permitting the temperature of the parison to equilibrate itself. The parison is then stretched, oriented to yield the desired biaxially oriented article, cooled and ejected.

Injection blow molding method

A method for the fabrication of a plastic preform suitable for use in the preparation of biaxially oriented hollow articles is described wherein the duration of the preform injection molding cycle is reduced, thereby enhancing the productivity of the injection molding step. This end is attained by injection molding and cooling, and supercooling and conditioning simultaneously at a single station of an injection molding machine at different positions within the station.

Apparatus for injection molding of plastic preform

Presaturated plastic preforms suitable for use in preparing molecularly oriented hollow articles from thermoplastic materials are obtained by adding controlled amounts of a saturant gas, under pressure, into a molten polymer stream residing in the screw channels of a screw plasticizer in a preform injection molding machine. The polymer so treated is then injected into cooled preform molds to obtain the desired article.

Saturated preform and method for preparation thereof

Molecular biaxially oriented hollow articles are obtained by injection blow molding using a novel apparatus. The technique involves the use of an inline, single stage injection blow molding apparatus wherein injection molding and cooling, and conditioning and stretch blow molding of parisons are all performed simultaneously at a single station at different positions within that station.

Injection blow molding apparatus

A novel procedure for circulating blowing air through an injection blow molded article during the blow cooling cycle of an injection molding process is described. The technique involves the use of a new core rod assembly which permits internal circulation of cool air during the blow cooling cycle of the process.

Method for injection blow molding

A novel procedure for circulating blowing air through an injection blow molded article during the blow cooling cycle of an injection molding process is described. The technique involves the use of a new core rod assembly which permits internal circulation of cool air during the blow cooling cycle of the process. The described assembly may also be used for reconditioning itself by the use of heated air, so avoiding the phenomenon of core rod freeze-up.

An improvement in the method of operating a molding apparatus for use in molding plastic and other materials is provided. The inner mold surfaces of the apparatus are flooded, during operation, with a dehumidified gas such as dry air to minimize condensation of moisture onto these surfaces. This dry air forms a field in the area of the mold surfaces to keep out the normally moist ambient air. The field is exhausted and recirculated to the supply source where it is regenerated and returned to the area of the mold surfaces. In this way, a continuous concentration of dry air is maintained in contact with the mold surfaces. One or more dry air curtains are also established around the dry air field to prohibit moist air from entering the field. The air curtain may be established from the same supply source as the dry field or from a separate source and may also be recirculated. A cloud of dry gas may be emitted outside of the air curtains to further inhibit the flow of moist ambient air to the mold surfaces.

Method for molding materials

A technique for internally cooling a blow molded article with a coolant comprising a mixture of subzero temperature dry air and water. A pressure swing dessicant bed type dryer and chiller are used to supply the dry air having a dew point of the order of -60.degree. F and a temperature ranging from -30.degree. to -50.degree. F for introduction into the blow molded article.

Method for blow molding and cooling plastic articles

Apparatus for injection blow molding

An improvement in the method of operating a molding apparatus as well as an improved apparatus for use in molding plastic and other materials is provided. The inner mold surfaces of the apparatus are flooded, during operation, with a dehumidified gas such as dry air to minimize condensation of moisture onto these surfaces. The dry air is supplied to a chamber surrounding one half of the mold and through channels in the mold onto the molding surfaces. This dry air forms a field in the area of the mold surfaces to keep out the normally moist ambient air. The field is exhausted through a chamber surrounding the other mold half and recirculated to the supply source where it is regenerated and returned to the first chamber. In this way, a continuous concentration of dry air is maintained in contact with the mold surfaces. One or more dry air curtains are established around the dry air field to prohibit moist air from entering the field.

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Whippany, NJ, United States of America

Leonard B Ryder