Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
  • B29C44/12—Incorporating or moulding on preformed parts, e.g. inserts or reinforcements
  • B29C44/1252—Removing portions of the preformed parts after the moulding step
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/44—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles
  • B29C33/48—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles with means for collapsing or disassembling
  • B29C33/50—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles with means for collapsing or disassembling elastic or flexible
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
  • B29C33/68—Release sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
  • B29C37/0003—Discharging moulded articles from the mould
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/34—Auxiliary operations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
  • B29C51/10—Forming by pressure difference, e.g. vacuum

Definitions

• This invention relates to the molding of foam articles using reactant chemicals which form foamed plastics, such as poIyurethanes.
• foam plastic articles be formed by molding processes using both open and closed molds, and capable of producing three dimensional objects used for packaging, for decorative effect, and for structural purposes among others.
• One consistent problem throughout such molding processes and apparatus used in practicing such methods Is that of obtaining a s.mooth surface finish on a molded article while also obtaining easy release of the molded article from the mold.
• certain foam materials of which thermosetting chemically blown foams, isocyanurates and polyurethane are examples, the unavailability of controlled surface finishes and freely releasing molds has severely restricted the usefulness of t hose materials.
• a further object of the present invention Is to accomplish ready release of a molded foam object from the mold in which the foam Is formed into a desired shape.
• the fluorocarbon polymer liner used prevents adhesion of the molded foam to the mold form, thereby permitting the finished article to be easily released.
• stripping of the moided article or object from the mold is accomplished by distending the liner with fluid pressure.
• Yet a further object of this invention is to provide molding apparatus for use in practicing the methods described above and in which a fluorocarbon polymer liner has been vacuum formed into the configuration and position required for proper functioning of the apparatus.
• a mold form is provided, a l iner film of the type described Is provided, and the liner is formed to the configuration of the mold.
• the liner may be dlstendable by fluid pressure.
• the liner may be adhered in use position and renewable as required to maintain efficiency of the molding apparatus.
• Figure 1 Is a perspective view of a molding apparatus in accordance with this invention, illustrating one step in a process of this invention
• Figure 2 is a schematic elevation view, partly in section, through the apparatus of Figure 1 and Illustrating another step in a process of this invention
• Figure 3 is a view similar to Figure 2 illustrating another step in a process in accordance with this invention.
• Figure 4 Is an exploded perspective view of the apparatus of Figures 1 through 3, showing another step in accordance with a process in accordance with this invention.
• the specific apparatus illustrated has a mold box generally indicated at 10, within which Is located a mold member 11. in the form illustrated, the box 10 Is generally square, defining a mold cavity of that configuration, and the member 11 Is convex or what may be referred to as a male mold member.
• the three dimensional article or object produced in the moid box 10 has a concavity for receiving some object to be packaged. It is contemplated that the invention here described is useful with other types of mold forms, as will be descrjbed.
• the mold box 10 has provision for vacuum forming a fluorocarbon film liner, which in the illustrated embodiment includes an air handling device generally indicated at 12.
• the mold box 10 and the member 11 therewithin have passageways formed therein for air flow, as is known generally to persons skilled in the arts of vacuum forming polymer films.
• a fluorocarbon polymer film generally indicated at 14 is used as a liner for the mold cavity defined within the box 10.
• Such films have in common the characteristics of being the slipperiest of all solids, essentially chemically inert, and of good mechanical strength. The mechanical strength of the films allows significant resistance to repetitive bending or folding stress, thereby aiding in avoiding microc
• Such films may be etched where appropriate, and vacuum formed using technology which is essentially known to persons of appropriate skill in the applicable vacuum forming art.
• the film 14 is positioned over an open side of the box 10 and retained in place by appropriate means such as edge clamps 15. Other forms of clamps may be used, and will be known to vacuuming forming technicians.
• the film 14 Is then heated and drawn into the cavity provided by the box 10 by the removal of air therefrom by the device 12. Heating may be accomplished by a convectlve air heater 16 blowing hot air against the film, or by a radiant heat source as Is known to skilled vacuum forming technicians.
• the liner being vacuum formed to the mold, the film takes on the configuration of the mold cavity and provides a slick, highly finished surface for the cavity.
• the mold is thus prepared for the introduction of foam reactants, which Is accomplished by delivering such chemicals through an appropriate nozzle or gun 18.
• foam reactants which Is accomplished by delivering such chemicals through an appropriate nozzle or gun 18.
• the nature of the chemicals used, and their delivery in such a way as to mix and begin a foaming reaction Is well known within the chemical industry and will not here be described in detail. It Is contemplated that the apparatus and methods of the present invention may be used with any such foam forming chemical system.
• the mold apparatus in accordance with this invention may have a cover 19 ( Figure 3) which may, in any appropriate manner, control the pressure during reaction and thus the density of the foam.
• the reactants introduced into the mold will form therewithin a molded article or object 20.
• the object 20 may be stripped or ejected from the mold by distending the film liner 14, as indicated in Figure 4.
• the air handling device 12 has been used to inflate the liner 14 by applying fluid pressure between the liner and the mold box 10.
• the object 20 formed by the molding process is removed from the mold.
• the mold is thus prepared for a repetition of the steps of drawing the liner into position by vacuum, introducing reactants for forming foam, molding an object, and ejecting the object from the mold.
• a succession of objects may thus be formed, all with the desired high surface finish.
• molding in an open sided mold may be acompllshed both with and without distending the film liner to strip the molded article from the mold.
• the mold employed may be either a male mold or a female mold, imparting either concave, convex, or compound shapes to the molded objects.
• the liner may be etched on one surface and adhered in place for use, then later stripped from the mold should replacement be necessary.
• the useful life of molds Is significantly extended, and molds made be made from less expensive materials.
• the liner which Is separate from or non-integral with the mold structure, to adjust to variations in thermal expansion and contraction between the liner and the mold structure which supports the liner during molding. This adjustment is believed to contribute to the avoidance of microcracking which Is known to be a characteristic of this invention.
• the liner may be formed to the desired configuration by techniques other than vacuum forming.
• the liner may be form by die casting, blow molding, pressing, injection molding, or extruding, so long as the desired configuration matching the supporting mold structure Is achieved while the liner is free to move separately from or be removed from the mold structure.
• vacuum forming may well be a preferred process for forming the liner, it Is recognized as being only one of the available means.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Pinball Game Machines (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=27038384

Family Applications (1)

Country Status (10)

Cited By (2)

Citations (3)

• 1983
  • 1983-12-27 EP EP84900480A patent/EP0131037A1/en not_active Withdrawn
  • 1983-12-27 WO PCT/US1983/002057 patent/WO1984002682A1/en not_active Application Discontinuation
  • 1983-12-27 JP JP84500550A patent/JPS60500409A/ja active Pending
• 1984
  • 1984-01-03 IL IL70613A patent/IL70613A0/xx unknown
  • 1984-01-04 ES ES528686A patent/ES528686A0/es active Granted
  • 1984-01-07 KR KR1019840000043A patent/KR840007379A/ko not_active Application Discontinuation
  • 1984-01-09 FI FI840074A patent/FI840074A0/fi not_active Application Discontinuation
  • 1984-01-09 PT PT77935A patent/PT77935B/pt unknown
  • 1984-09-04 DK DK421884A patent/DK421884A/da not_active Application Discontinuation
  • 1984-09-06 NO NO843546A patent/NO843546L/no unknown
• 1985
  • 1985-01-28 ES ES539896A patent/ES8605181A1/es not_active Expired

Patent Citations (3)

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