CA1102067A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Method and apparatus for molding expandable polystyrene
Assignee: BASF Corp
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Filing: 1977-12-20
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Granted: 1981-06-02
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Expires: 1997-12-20
Abstract
Abstract METHOD AND APPARATUS FOR MOLDING EXPANDABLE POLYSTYRENE Abstract of the Disclosure This invention relates to improvements in molding expandable polystyrene, particularly for molding high density tubular parts, in which the molding tool is made with a sintercore metal on each side of the mold cavity, and which has an internal vacuum chamber, external steam jackets, and compressed air means capable of communicating with both the interior vacuum chamber and the exterior steam jacket. The process sequence comprise the steps of (l) applying a vacuum to the inner chamber of the mold, (2) filling the mold with expandable polystyrene beads, (3) charging the jacket with steam, said vacuum being maintained in the inner chamber during steps 2 and 3 to improve mold filling and steaming through the sintercore, (4) cooling the jacket with compressed air, or a water mist and (5) removing the jacket and then the molded article, with the article removal being assisted by application of compressed air to the inner chamber of the mold.
Inventors
- 👤 Herbert M. Gahmig
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-06 10:27
CPC Classifications
—
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
134 words
A method of molding expandable polystyrene comprising the steps of providing a mold assembly comprising a mold having a cavity substantially enclosed by a smooth permeable material, a first chamber on one side of the mold cavity, and a second chamber on the other side of the mold cavity, evacuating said first chamber to provide a vacuum therein, placing an amount of expandable polystyrene beads in said mold cavity, charging said second chamber with steam while the first cavity is under vacuum, whereby steam will move through the permeable mold walls and mold cavity into the first chamber, said steam being charged for a time sufficient to expand and fuse the expandable poly-styrene within the entire mold cavity, shutting off said steam, cooling the molded article, and removing the molded article from the mold.
Claim 2
Independent Claim
134 words
A method of molding expandable polystyrene comprising the steps of providing a mold assembly comprising a mold having a cavity substantially enclosed by a smooth permeable material, a first chamber on one side of the mold cavity, and a second chamber on the other side of the mold cavity, evacuating said first chamber to provide a vacuum therein, placing an amount of expandable polystyrene beads in said mold cavity, charging said second chamber with steam while the first cavity is under vacuum, whereby steam will move through the permeable mold walls and mold cavity into the first chamber, said steam being charged for a time sufficient to expand and fuse the expandable poly-styrene within the entire mold cavity, shutting off said steam, cooling the molded article, and removing the molded article from the mold.
Claim 3
Dependent Claim
32 words
A method of molding expandable polystyrene, as defined in claim 1, in which compressed air is provided in said first chamber during the step of removing the expanded polystyrene from the mold.
Claim 4
Dependent Claim
30 words
A method of molding expandable polystyrene, as defined in claim 1, in which the cooling step is effected by blowing compressed air or a water mist through the second chamber.
Claim 5
Dependent Claim
22 words
4, A method of molding expandable polystyrene, as defined in claim 1, in which the mold is constructed of a metallic material.
Claim 6
Dependent Claim
28 words
A method of molding expandable polystyrene, as defined in claim 1, which also comprises the step of contacting the expandable polystyrene with a fine mist of mineral oil.
Claim 7
Independent Claim
184 words
A method of molding expandable polystyrene into an open-ended, closed, sheet-like configuration, com-prising the steps of providing a mold assembly, comprising an inner mold section formed with smooth permeable wall means having an interior surface defining an interior chamber and an exterior surface shaped to define the interior surface of the open-ended, closed, sheet-like configuration to be molded, and an outer mold section formed with smooth per-meable wall means having an inner surface shaped to define the exterior surface of the configuration to be molded, said inner and outer section fittable to provide a mold cavity therebetween, and a jacket formed to provide an exterior chamber adjacent to the outer surface of the outer section of the mold, evacuating said interior chamber to provide a vacuum therein, placing expandable polystyrene in said mold cavity, charging said exterior chamber with steam for a time sufficient to expand the expandable polystyrene and fill the mold cavity therewith while maintaining the inner chamber under vacuum, cooling the expanded polystyrene, removing the jacket and the outer section of the mold, and removing the molded polystyrene from the mold.
Claim 8
Independent Claim
184 words
A method of molding expandable polystyrene into an open-ended, closed, sheet-like configuration, com-prising the steps of providing a mold assembly, comprising an inner mold section formed with smooth permeable wall means having an interior surface defining an interior chamber and an exterior surface shaped to define the interior surface of the open-ended, closed, sheet-like configuration to be molded, and an outer mold section formed with smooth per-meable wall means having an inner surface shaped to define the exterior surface of the configuration to be molded, said inner and outer section fittable to provide a mold cavity therebetween, and a jacket formed to provide an exterior chamber adjacent to the outer surface of the outer section of the mold, evacuating said interior chamber to provide a vacuum therein, placing expandable polystyrene in said mold cavity, charging said exterior chamber with steam for a time sufficient to expand the expandable polystyrene and fill the mold cavity therewith while maintaining the inner chamber under vacuum, cooling the expanded polystyrene, removing the jacket and the outer section of the mold, and removing the molded polystyrene from the mold.
Claim 9
Dependent Claim
24 words
A method of molding expandable polystyrene, as defined in claim 6, in which the mold cavity is shaped to form a substantially tubular article.
Claim 10
Dependent Claim
23 words
A method of molding expandable polystyrene, as defined in claim 6, in which the mold sections are composed of a sintercore metallic material.
Claim 11
Dependent Claim
33 words
A method of molding expandable polystyrene, as defined in claim 6, in which compressed air is charged into the interior chamber to assist in rapid removal of the molded article from the mold.
Claim 12
Dependent Claim
24 words
A method of molding expandable polystyrene, as defined in claim 6, in which the operations to the interior chamber and exterior chamber are reversed.
Claim 13
Dependent Claim
25 words
A method of molding expandable polystyrene, as defined in claim 6, in which the expanded product is of densities above 2 pounds per cubic foot.
Claim 14
Dependent Claim
20 words
A method of molding expandable polystyrene, as defined in claim 11, in which the expanded product is tubular in configuration.
Claim 15
Dependent Claim
29 words
A method of molding expandable polystyrene, as defined in claim 6, in which the cooling step is effected by blowing compressed air or a water mist through the chambers.
Claim 16
Dependent Claim
168 words
A mold assembly for forming a high density expandable polystyrene article of an open-ended, closed-curved, sheet-like configuration having an interior surface and an exterior surface, comprising an inner mold section formed with smooth permeable wall means having an interior surface defining an interior chamber and an exterior surface shaped to match the interior surface of the article to be molded and provide a part of a mold cavity, an outer mold section formed with smooth permeable wall means having an inner surface shaped to define the exterior surface of the article to be molded and formed for fitting against said inner section to form said mold cavity, a jacket means disposed to provide an ex-terior chamber adjacent to the outer surface of the outer section of the mold, said jacket means and outer mold sections being removable to expose the mold cavity, means for evacuating the interior chamber to provide a vacuum within the mold, means for supplying steam to the jacket, and means for cooling the mold.
Claim 17
Dependent Claim
168 words
A mold assembly for forming a high density expandable polystyrene article of an open-ended, closed-curved, sheet-like configuration having an interior surface and an exterior surface, comprising an inner mold section formed with smooth permeable wall means having an interior surface defining an interior chamber and an exterior surface shaped to match the interior surface of the article to be molded and provide a part of a mold cavity, an outer mold section formed with smooth permeable wall means having an inner surface shaped to define the exterior surface of the article to be molded and formed for fitting against said inner section to form said mold cavity, a jacket means disposed to provide an ex-terior chamber adjacent to the outer surface of the outer section of the mold, said jacket means and outer mold sections being removable to expose the mold cavity, means for evacuating the interior chamber to provide a vacuum within the mold, means for supplying steam to the jacket, and means for cooling the mold.
Claim 18
Dependent Claim
27 words
A mold assembly, as defined in claim 14, in which the permeable wall means of the inner and outer mold sections are each composed of sintered metal.
Claim 19
Dependent Claim
16 words
A mold assembly, as defined in claim 14, in which the mold cavity is substantially tubular.
Claim 20
Dependent Claim
30 words
A mold assembly, as defined in claim 14, in which the means for cooling the mold comprises a means for supplying compressed air or a water mist to the jacket.
Claim 21
Dependent Claim
24 words
A mold assembly, as defined in claim 14, which also comprises means for supplying compressed air or a water mist to the interior chamber.
Claim 22
Dependent Claim
26 words
A mold assembly as defined in claim 14 where the application of steam, vacuum and cooling can be re-versed from the inner to the outer jacket.
References Cited (Backward Citations)
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