Foamed Polystyrene Mold Filling Patents (Class 264/DIG10)
  • Patent number: 5591496
    Abstract: A method of making a composite sheet material in which at least one lamina of previously unused expanded polystyrene is bonded to a second lamina of recycled expanded polystyrene. The laminae are continuously formed from separate extruders and are merged promptly after extrusion. Heat is applied to the laminae just before they are merged.
    Type: Grant
    Filed: July 13, 1993
    Date of Patent: January 7, 1997
    Assignee: Linpac Plastics International Limited
    Inventors: Michael C. Anderson, Anthony J. Heap, Horst-Ditmar Grone
  • Patent number: 5308560
    Abstract: A process for producing a moulding from an expanded styrene polymer. This process comprises applying gas pressure to particles of the polymer, introducing the particles under pressure into a mould, and reducing the pressure to allow at least some of the particles to expand in the mould and bond together to form the moulding.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: May 3, 1994
    Assignee: M. Y Trondex Limited
    Inventors: Norman W. Bibby, Oskar L. Willi
  • Patent number: 5271886
    Abstract: A process and apparatus for rapidly expanding and molding carbon dioxide-impregnated polymer particles is disclosed. The process involves expanding the impregnated particles in a moving stream of pressurized saturated steam or super-heated steam, directing the resulting stream of pre-expanded particles into a mold, and molding the particles into a foamed object. Apparatus suitable for use with the process is also disclosed.
    Type: Grant
    Filed: October 14, 1992
    Date of Patent: December 21, 1993
    Assignee: Arco Chemical Technology, L.P.
    Inventors: William Collom, Dennis Fuller, Joseph Kinslow, Bernard H. Meyer, Richard H. Immel
  • Patent number: 5238624
    Abstract: A method and machine for manufacturing polystyrene foam products, whereby a mold, including a first and second half mold defining a molding chamber when closed, is loaded, with the two half molds locked in the closed position, on to the machine and into an operating position wherein the mold is connected automatically to granular polystyrene and utility fluid supply lines. In the operating position, the two half molds are rendered mutually mobile; the first half mold, connected to the supply lines, remaining locked to a fixed frame on the machine, and the second half mold remaining locked to a mobile frame on the machine.
    Type: Grant
    Filed: June 10, 1991
    Date of Patent: August 24, 1993
    Assignee: Bazzica Engineering Di Carlo Bazzica & C. S.A.S.
    Inventor: Carlo Bazzica
  • Patent number: 5206271
    Abstract: Expandable styrene polymers which contain from 10 to 90% by weight of a crosslinked styrene-diene copolymer containing from 2 to 45% by weight of the diene, and from 1 to 10% by weight of a C.sub.3 -to C.sub.6 -hydrocarbon as blowing agent can be processed to give foams which have high resistance to aromatics.
    Type: Grant
    Filed: March 24, 1992
    Date of Patent: April 27, 1993
    Assignee: BASF Aktiengesellschaft
    Inventors: Klaus Hahn, Uwe Guhr, Hans Hintz, Hans Hoenl
  • Patent number: 5190986
    Abstract: Elastomeric low density foamable compositions are described which are prepared from blends comprised of a major amount of a block copolymer comprised of an alkenyl aromatic and a conjugated diene and a minor amount of one or more other thermoplastic resins. Also described are such foamable compositions wherein such blends are comprised of a major amount of a triblock copolymer of the A-B-A type and a minor amount of polystyrene resin and/or polyphenylene ether resin. Also described are processes for preparing such low density foamable compositions and articles made therefrom.
    Type: Grant
    Filed: December 6, 1991
    Date of Patent: March 2, 1993
    Assignee: General Electric Company
    Inventors: Richard B. Allen, Popkin Shenian
  • Patent number: 5166221
    Abstract: Expandable styrene polymers which contain from 10 to 90% by weight of a crosslinked styrene-diene copolymer containing from 2 to 45% by weight of the diene, and from 1 to 10% by weight of a C.sub.3 - to C.sub.6 -hydrocarbon as blowing agent can be processed to give foams which have high resistance to aromatics.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: November 24, 1992
    Assignee: BASF Aktiengesellschaft
    Inventors: Klaus Hahn, Uwe Guhr, Hans Hintz, Hans Hoenl
  • Patent number: 5130340
    Abstract: Elastomeric low density foamable compositions are described which are prepared from blends comprised of a major amount of a block copolymer comprised of an alkenyl aromatic and a conjugated diene and a minor amount of one or more other thermoplastic resins. Also described are such foamable compositions wherein such blends are comprised of a major amount of a triblock copolymer of the A-B-A type and a minor amount of polystyrene resin and/or polyphenylene ether resin. Also described are processes for preparing such low density foamable compositions and articles made therefrom.
    Type: Grant
    Filed: July 9, 1990
    Date of Patent: July 14, 1992
    Assignee: General Electric Company
    Inventors: Richard B. Allen, Popkin Shenian
  • Patent number: 5114640
    Abstract: A method for making low density (0.8-1.1 lb./cu.ft.) expanded polymeric products uses blowing agent in an amount of any from 2 to 4.4 weight percent and aging periods of from 1 to 80 hours after each expansion step. The process uses 2 to 5 expansion steps and a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.
    Type: Grant
    Filed: October 15, 1991
    Date of Patent: May 19, 1992
    Assignee: BASF Corporation
    Inventors: William H. Harclerode, John C. Knutsen, Barry J. Pekich, John V. Wiman, John C. Voss
  • Patent number: 5115066
    Abstract: A polystyrene polymer as well as an expandable polystyrene formulation comprises a polystyrene polymer having a particular molecular weight distribution. The polymer itself exhibits a polydispersity of from about 1 to less tha 2.0, a weight average molecular weight of greater than about 200,000 to about 300,000, and an M.sub.z :M.sub.n of from about 2 to less than about 3.0. Furthermore, the polystyrene polymer is branched to from 0 to less than 5 weight percent.The expandable polystyrene formulation comprises a polystyrene polymer exhibiting a polydispersity of from about 1.0 to less than 2.5, a weight average molecular weight of from greater than about 180,000 to about 300,000, an M.sub.z :M.sub.n of from about 2 to about 4.5. The polystyrene polymer is present in an amount of from about 94.5 weight percent to about 98 weight percent, based on the total weight of the formulation, and the polystyrene polymer is branched to from 0 to less than 5 weight percent.
    Type: Grant
    Filed: October 15, 1991
    Date of Patent: May 19, 1992
    Assignee: BASF Corporation
    Inventors: Eugene K. Zimmermann, Bernhard Wagner, William E. Volz, William H. Harclerode, John V. Wiman, John C. Voss
  • Patent number: 5110837
    Abstract: A method for making low density (0.8-1.1 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: May 5, 1992
    Assignee: BASF Corporation
    Inventors: William H. Harclerode, William E. Volz, John V. Wiman, John C. Voss, Barry J. Pekich, John C. Knutsen
  • Patent number: 5110836
    Abstract: A method for making low density (0.8-1.1 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent and aging periods of from 1 to 80 hours after each expansion step. The process uses 2 to 5 expansion steps and a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commerically viable processes for making expanded polystyrene products. The process can be used with or without a molding step.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: May 5, 1992
    Assignee: BASF Corporation
    Inventors: William H. Harclerode, John C. Knutsen, Barry J. Pekich, John V. Wiman, John C. Voss
  • Patent number: 5110524
    Abstract: A method for making low density (0.8-1.1 lb/cu. ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.
    Type: Grant
    Filed: October 15, 1991
    Date of Patent: May 5, 1992
    Assignee: BASF Corporation
    Inventors: William H. Harclerode, William E. Volz, John V. Wiman, John C. Voss, Barry J. Pekich, John C. Knutsen
  • Patent number: 5086078
    Abstract: A method for making low density (0.8-2 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent, the process emitting blowing agent during processing in an amount of from only about 0.3 to about 2.5 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commerically viable processes for making expanded polystyrene products. The process can be used with or without a molding step.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: February 4, 1992
    Assignee: BASF Corporation
    Inventors: William H. Harclerode, Eugene K. Zimmermann, Barry J. Pekich, John C. Knutsen, John V. Wiman, John C. Voss
  • Patent number: 5037592
    Abstract: To make a molded article from expandable synthetic resin particles, especially polystyrene particles, the cooling of the individual mold wall portions is effected exclusively by evaporating condensate obtained from stream, advantageously condensate which accumulates in stream compartments on the exterior or back sides of the mold walls which was fed in for heating of the mold wall portions and fusing the synthetic resin particles. This evaporation of condensate is effected on the back surfaces of the mold wall portions facing the steam compartments because of a low pressure or suction produced in the steam compartments. The condensate is fed in hot at or just below the boiling temperature of the condensate. Surfaces of the mold wall portions facing the steam compartment have increased surface area by reason of spherical surface-area increasing elements which form constricted passages between a plurality of interior reservoir cavities and the outside steam compartment.
    Type: Grant
    Filed: April 7, 1989
    Date of Patent: August 6, 1991
    Assignee: Erlenbach GmbH & Co. KG
    Inventor: Hans Erlenbach
  • Patent number: 4986942
    Abstract: A single-piece foam pattern for use in the lost foam casting of a ported cylinder sleeve is formed in a molding tool having a pair of displaceable elements and a removable center core. Ports, of preselected size, shape and location, are defined by movable cores which are extended into position between the displaceable elements and the center core. Following introduction of a molding material, the movable cores are retracted after which the mold elements and center core are separated and the foam pattern is removed.
    Type: Grant
    Filed: March 22, 1988
    Date of Patent: January 22, 1991
    Assignee: Outboard Marine Corporation
    Inventors: Christopher R. Irgens, Francis V. Bailey
  • Patent number: 4822542
    Abstract: This invention relates to a method and apparatus for improving not only the quality of the production of molded foamable thermoplastic resin particles converted into fusion-bonded materials but also the output by protecting the resin from atmospheric pressure by pressurizing the particles and heating the particles to soften the same.
    Type: Grant
    Filed: July 23, 1987
    Date of Patent: April 18, 1989
    Assignee: Japan Styrene Paper Corporation
    Inventors: Hedeki Kuwabara, Atusi Kitagawa, Masato Kanbe
  • Patent number: 4818451
    Abstract: A method of molding pre-foamed synthetic resin particles is described, which comprises increasing the pressure in a mold cavity with a pressurized gas, charging the mold cavity with pre-foamed synthetic resin particles as they are compressed with a gas pressurized to a pressure higher than the pressure in the mold cavity and heating the charged pre-foamed synthetic resin particles with steam so that they are fused together or expanded and fused together to form a foamed molded article, wherein a pressure detector is provided in a conduit for conveying the pre-foamed synthetic resin particles into the mold cavity as they are carried by the pressurized gas or at an inlet portion of a charging port leading to the mold cavity, and the supply of pre-foamed synthetic resin particles into the mold cavity is stopped when the pressure detected by the detector exceeds the pressure in the mold cavity by a predetermined amount.
    Type: Grant
    Filed: April 2, 1987
    Date of Patent: April 4, 1989
    Assignee: Mitsubishi Yuka Badische Co., Ltd.
    Inventors: Masakazu Arai, Masahiro Tanaka
  • Patent number: 4800050
    Abstract: A control process for foaming and fusing plastics in a foaming and fusing device, and a fusing device for carrying out the process, in which the control process works in cycles, each cycle consists of phases which are at least an injection phase, a heating phase, a fusion phase, a cooling phase and a mould release phase, such phases being started and completed depending on control criteria comprising a time period, a pressure or a temperature limit value for the conditions evolving in the device such control criteria belonging to a certain cycle comprising a control criteria set, and with each cycle quality values of predetermined characteristics determined by measurements taken from the respective plastic part or an agglomerate cake situated in the device, a new set of control criteria being generated for each new cycle from prior control criteria depending from the quality values measured with such prior cycle of the control process, wherein the quality values of each cycle are combined to a deviation which
    Type: Grant
    Filed: November 20, 1986
    Date of Patent: January 24, 1989
    Assignee: Ortwin Hahn
    Inventors: Ortwin Hahn, Johannes Hummler
  • Patent number: 4756859
    Abstract: A method for obtaining expanded polystyrene products comprising portions of comparatively very different densities and thus of different mechanical strengths, in which a first mass of pre-expanded polystyrene beads of greater density is caused to partially cohere by means of steam, the resultant mass is placed in a mould of greater dimensions, said mould is completely filled with polystyrene beads of density less than the preceding, and cohesion is completed therein.
    Type: Grant
    Filed: May 28, 1986
    Date of Patent: July 12, 1988
    Assignee: Plastbau A.G.
    Inventor: Piero Cretti
  • Patent number: 4695343
    Abstract: Method and apparatus is provided for reinforcing a structural member of a vehicle body by the use of adhesively bonded together glass macrospheres of 3 to 9 mm. in diameter. The adhesive is not more than about 40% by weight of the mixture so that voids remain between the adjacent macrospheres to permit airflow through the reinforcement and the reinforced structural member upon curing adhesive. The adhesive may be curable at ambient temperature or may be a high temperature curable adhesive which is cured in a vehicle body paint curing over to bond the macropsheres to one another and to the structural member. The adhesion of the macrospheres to the structural member may be facilitated by an epoxy coated flexible sheet material lining the walls of the structural member. The adhesive coated macrospheres may be closely packed into the structural member by pouring or blowing.
    Type: Grant
    Filed: May 19, 1986
    Date of Patent: September 22, 1987
    Assignee: General Motors Corporation
    Inventor: Joseph S. Wycech
  • Patent number: 4610836
    Abstract: Method and apparatus is provided for reinforcing a structural member of a vehicle body by the use of adhesively bonded together glass macrospheres of 3 to 9 mm. in diameter. The adhesive is not more than about 40% by weight of the mixture so that voids remain between the adjacent macrospheres to permit airflow through the reinforcement and the reinforced structural member upon curing adhesive. The adhesive may be curable at ambient temperature or may be a high temperature curable adhesive which is cured in a vehicle body paint curing oven to bond the macrospheres to one another and to the structural member. The adhesion of the macrospheres to the structural member may be facilitated by an epoxy coated flexible sheet material lining the walls of the structural member. The adhesive coated macrospheres may be closely packed into the structural member by pouring or blowing.
    Type: Grant
    Filed: November 23, 1984
    Date of Patent: September 9, 1986
    Assignee: General Motors Corporation
    Inventor: Joseph S. Wycech
  • Patent number: 4456443
    Abstract: A machine for molding sheets of foamed material includes an upright stationary steam chest having opposing perforated external faces, and a pair of movable assemblies abuttable with the opposite faces of the steam chest to define mold cavities therewith. Each cavity forming assembly includes a mold frame extending normal to a face of the steam chest, and a platen positioned within and coupled to the mold frame. Jackscrews move each mold frame into and out of abutment with the steam chest, and also move each platen relative to its respective mold frame toward and away from the steam chest. A method of molding sheets of foamed material is also disclosed wherein heated polystyrene beads are squeezed by the movable platens to a predetermined thickness to provide a board having the desired dimensions and density.
    Type: Grant
    Filed: November 26, 1982
    Date of Patent: June 26, 1984
    Assignee: Design Engineering Service Inc.
    Inventor: John Rabotski
  • Patent number: 4382757
    Abstract: An improved molding apparatus for expanding beads of polystyrene material into large blocks in the manufacture of insulating material. The mold apparatus has walls made from a plurality of tubular wall members arranged in horizontal, side-by-side relation. The wall members are mounted transversally within encircling frames. Steam is supplied to each wall member, and from within each wall member, into the mold cavity to expand the polystyrene beads held therein into a block. An improved device is also provided to remove the block from the mold cavity.
    Type: Grant
    Filed: April 1, 1981
    Date of Patent: May 10, 1983
    Assignee: Mansonville Plastics Limited
    Inventors: Richard N. Roy, Clerval Labbe, Albert Korman
  • Patent number: 4304810
    Abstract: Low density, lightweight foam articles may be provided with certain portions or regions thereof, that are reinforced, having higher density and strength, obtained by compression of the foam in these locations, during or after formation of the foam. Such locations may be made sufficiently strong and dense to allow the article to be attached in place by fastening means, imbedded therein. The increase in density can be as much as from 5 pcf to 10 pcf or higher, depending upon the particular application.Many foam materials, capable of being molded, extruded, or otherwise shaped to a predetermined configuration, may be made with this combination of high and low density, including foams of styrenic polymer or copolymer compositions, urethanes, vinyls, and even non-thermoplastic based materials, such as phenolic foams.
    Type: Grant
    Filed: July 17, 1980
    Date of Patent: December 8, 1981
    Assignee: Arco Polymers, Inc.
    Inventors: Richard L. Gates, Dennis J. Fuller, Thomas L. Wolford
  • Patent number: 4295810
    Abstract: A building block having at least one chamber therein which is filled with a foamed plastic material consisting of particles interconnected at their surfaces to form gas-permeable interstices. The block is formed by filling the chamber with a loose fill of the foamed plastic material and then fusing the particles to each other by blowing hot gas through an injection lance inserted in the fill.
    Type: Grant
    Filed: June 5, 1979
    Date of Patent: October 20, 1981
    Assignee: Veit Dennert KG Baustoffbetriebe
    Inventors: Heinz Dennert, Hans V. Dennert
  • Patent number: 4288337
    Abstract: A lightweight mixed dielectric and a manufacturing method thereof is described, which is prepared by mixing metal-coated expanded particles of plastic, glass or silica, thin-wall metal pipes or metal coated thin-wall plastic pipes and uncoated expanded particles of plastic, glass or silica and then forming the resulting mixture into a desired shape by thermal expansion or by the use of binder with the provision that these uncoated expanded particles are only made of plastic when the forming step is carried out by thermal expansion.
    Type: Grant
    Filed: August 31, 1979
    Date of Patent: September 8, 1981
    Assignee: Tokyo Keiki Company Limited
    Inventors: Hiroshi Ota, Noboru Sakuma, Takeki Takarabe, Isao Takiguchi
  • Patent number: 4278628
    Abstract: Expandable thermoplastic polymer beads are introduced into a tank and are agitated therein in a heated moisture-free condition. The beads are pressurized within the tank with a hot gaseous medium to soften them and are then subjected within the tank to a selected degree of vacuum to expand the beads or particles. The vacuum is removed and atmospheric pressure is re-established in the tank. The expanded hot moisture-free particles are introduced into a mold where they are fused into an integral mass, followed by cooling of the fused mass within the mold to form an outer skin on the mass. The fused mass is ejected from the mold.
    Type: Grant
    Filed: August 31, 1979
    Date of Patent: July 14, 1981
    Assignee: Southeastern Foam Products, Inc.
    Inventors: Robert L. Montgomery, Stuart B. Smith
  • Patent number: 4274818
    Abstract: Expandable thermoplastic polymer beads are introduced into a tank and are agitated therein in a heated moisture-free condition. The beads are pressurized within the tank with a hot gaseous medium to soften them and are then subjected within the tank to a selected degree of vacuum to expand the beads or particles. The vacuum is removed and atmospheric pressure is re-established in the tank. The expanded hot moisture-free particles are introduced into a mold where they are fused into an integral mass, followed by cooling of the fused mass within the mold to form an outer skin on the mass. The fused mass is ejected from the mold.
    Type: Grant
    Filed: August 31, 1979
    Date of Patent: June 23, 1981
    Assignee: Southeastern Foam Products, Inc.
    Inventors: Robert L. Montgomery, Stuart B. Smith
  • Patent number: 4272935
    Abstract: A thermally-insulating, non-flammable, air-permeable insulation for installation in the field, for example, in closed cavities between the walls of a house. A multitude of individually preformed, foamed plastic particles are initially entrained in a carrier stream, and thereupon drenched with a settable film-forming, non-flammable, liquid substance, such as a sodium silicate solution. The liquid substance sets to form a film which covers and adheres the particles to one another to form a thermally-insulating dense structural aggregate mass having structural integrity, resistance to fire, and venting capability. A method of making and installing the insulation, and a preferred apparatus therefor, are disclosed.
    Type: Grant
    Filed: February 19, 1980
    Date of Patent: June 16, 1981
    Assignee: Retro-Flex, Inc.
    Inventors: Sidney Lukas, Timothy E. Golden, Patrick J. Lunarola, Michael G. Mard
  • Patent number: 4266928
    Abstract: The present invention relates to a filling device for introducing pre-foamed, post-expandable thermoplastics into molds for the production of moldings from plastic foams, especially from pre-foamed polystyrene foam, for example Styropor or Styrocell, in which the pre-foamed plastic is introduced in granular form into the mold by reason of a pressure difference existing between the stock container for the plastic granules and the mold and/or introduction of injected air. The filling device essentially consists of a cylindrical piston case with a lateral feed pipe for the plastic granules and a piston which is movable in the longitudinal direction within the cylindrical piston, for closing the mold inlet orifice after filling has taken place. The filling device according to the invention is characterized by a movable shut-off sleeve, which, by means of a spring, blocks the supply of granules when the piston has passed the feed pipe in the direction towards the mold.
    Type: Grant
    Filed: November 13, 1979
    Date of Patent: May 12, 1981
    Assignee: CIVAG AG Institut fur Verpackungsforschung
    Inventors: Richard Weidner, Ortwin Hahn
  • Patent number: 4233006
    Abstract: Apparatus for molding expandable thermoplastic resin particles having opposed mold platens. The platens having male and female mold members mounted thereon. The first platen having heated and cooled male mold members mounted thereon, and the second platen having heated and cooled female mold members mounted thereon. Tie bars extending between the first and second platens. Means for feeding expandable thermoplastic resin particles to the mold cavities defined by the male and female mold members when they are engaged together. Means for transfering the mold members from a first position wherein the heated and cooled mold members on the respective platens would be opposed to each other, and in a second position wherein the heated mold member on one platen would be opposed to the cool mold member on the other opposing platen. Means to clamp the mold members together during molding of the expandable thermoplastic resin particles.
    Type: Grant
    Filed: October 10, 1978
    Date of Patent: November 11, 1980
    Assignee: Wheaton Industries
    Inventor: Walter Panas
  • Patent number: 4076782
    Abstract: In the process where a shaped product of expanded polystyrene is continuously produced by passing preliminarily expanded beads of polystyrene interposed inside a carrying means comprising a circulating steam-permeable single belt or a set of belts of the same nature through a pressurized steam chamber provided with pressure-sealing means at the inlet and the outlet thereof, thereby closely integrating the beads into a sheet through softening and expansion of the beads by steam heating, then cooling the resulting shaped product, and separating the shaped product from the carrying belt or belts, while withdrawing the shaped product to a successive step and returning the carrying belt or belts to the inlet side of the pressurized steam chamber, at least one of the surfaces of the carrying belt(s) is wetted with water before supplying the preliminarily expanded beads onto the belt(s) on the inlet side of the pressurized steam chamber, and thereafter the preliminarily expanded beads are supplied in excess onto the
    Type: Grant
    Filed: February 17, 1976
    Date of Patent: February 28, 1978
    Assignee: Polymer Processing Research Institute Ltd
    Inventors: Masahide Yazawa, Teruo Kubo, Kunio Suzuki
  • Patent number: 4032609
    Abstract: An energy saving and material conserving method and apparatus are provided for expanding and molding expandable thermoplastic polymer particles. Especially significant is the ability to produce molded objects of generally uniform density in the higher density range in the order of 4-15 pounds per square inch, or greater, as well as lower density molded objects due to improved control of the particle expansion.The particles are partially expanded in a vessel in a heated substantially dry atmosphere and agitated in a manner to provide uniform heating thereof. After an initial heating period to soften and partially expand the particles they are subjected to superatmospheric pressure to substantially prevent further expansion and are discharged and conveyed to a mold for further expansion therein.
    Type: Grant
    Filed: July 22, 1975
    Date of Patent: June 28, 1977
    Assignee: Foster Grant Co., Inc.
    Inventor: Stuart B. Smith