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
  • 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
  • B29C51/04—Combined thermoforming and prestretching, e.g. biaxial stretching
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D83/00—Containers or packages with special means for dispensing contents
  • B65D83/14—Containers for dispensing liquid or semi-liquid contents by internal gaseous pressure, i.e. aerosol containers comprising propellant
  • B65D83/60—Containers for dispensing liquid or semi-liquid contents by internal gaseous pressure, i.e. aerosol containers comprising propellant with contents and propellant separated
  • B65D83/62—Containers for dispensing liquid or semi-liquid contents by internal gaseous pressure, i.e. aerosol containers comprising propellant with contents and propellant separated by membranes, bags or the like
• • 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
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/16—Cooling
  • B29C2035/1616—Cooling using liquids
• • 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
  • B29C2791/00—Shaping characteristics in general
  • B29C2791/004—Shaping under special conditions
  • B29C2791/006—Using vacuum
• • 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
  • B29C2793/00—Shaping techniques involving a cutting or machining operation
  • B29C2793/009—Shaping techniques involving a cutting or machining operation after shaping
• • 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
• • 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
  • B29C51/08—Deep drawing or matched-mould forming, i.e. using mechanical means only
• • 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
  • B29C51/14—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 using multilayered preforms or 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
  • 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
  • B29C51/26—Component parts, details or accessories; Auxiliary operations
  • B29C51/44—Removing or ejecting moulded articles
  • B29C51/445—Removing or ejecting moulded articles from a support after moulding, e.g. by cutting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2905/00—Use of metals, their alloys or their compounds, as mould material
  • B29K2905/02—Aluminium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2911/00—Use of natural products or their composites, not provided for in groups B29K2801/00 - B29K2809/00, as mould material
  • B29K2911/14—Wood, e.g. woodboard or fibreboard
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
  • B29K2995/0037—Other properties
  • B29K2995/0065—Permeability to gases
  • B29K2995/0067—Permeability to gases non-permeable

Definitions

• This invention relates to pressurized dispenser packages, such as aerosol packages, wherein the product to be dispensed and the pressure-generating media, i.e. the propellant, are maintained in isolation through separation on opposite sides of a barrier.
• An aerosol package of this type is generally referred to as a "barrier pack" aerosol package.
• Aerosol barrier packs of the prior art have been of at least three general types.
• the barrier is a piston-like component that is mounted in the container in sliding relation to the inside surface of the container.
• the product to be dispensed is disposed on the valved side of the piston and the propellant, which generates pressure within the container, is on the opposite side of the piston.
• Aerosol Handbook Second Edition, 1982, there i described a piston-type aerosol dispenser marketed by America Can Company under the trade-name "Mira-Flo".
• the piston skirt is designed to seal against th sides of the container to prevent the propellant gas fro passing into the product chamber on the other side of th piston.
• Actuation of the aerosol discharge valve causes reduction in pressure in the product chamber thereby resultin in the pressure in the propellant chamber urging the pisto toward the discharge valve and causing the discharge of product through the discharge valve.
• Examples of a piston-type barrier pack are described in United States Patent Nos. 3,022,923, 3,756,476 and 3,929,132.
• a flexible, collapsible bag is affixed within the container opening either to the aerosol discharge valve or to the bead of the container opening.
• the Continental Can Company in the late 1960's introduced an aerosol barrier dispenser known as the "Sepro- Can" .
• the Sepro-Can includes an interior plastic product bag having an opening that is attached to the valve opening at the top of the container.
• the side walls of the bag extend along the side walls of the container and are pleated like an accordion so the bag can collapse inward and upward under the influence of pressure in the remainder of the container as the bag is emptied.
• Patents which illustrate a barrier pack of the second type are set forth in U.S. Patent Nos. 3,788,521, 3,896,970 and 4,067,499. Modifications of barrier packs of the second type include attaching the bag to the side wall of the container or to the joint formed between the side wall of the container and the top of the container.
• a third type of prior art barrier pack is an unfolding cup-shaped barrier wherein the barrier has an outer wall terminating in a sealing flange, said outer wall being disposed contiguous to the inner wall of the container.
• the inner wall of the barrier is initially folded within the outer wall, the inner wall terminating in an end closing portion.
• the barrier is contained in a valved aerosol container and sealed at the joint formed between the sidewall and the bottom end closure of the container. Product is admitted through the valved opening of the container and propellant through a port in the bottom end closure of the container.
• Actuation of the valve reduces the pressure in the product compartment and results in the inner wall of the barrier unfolding from within the outer wall of the barrier and causing the end-closing portion of the inner wall of the barrier to advance and thereby urge the product toward the discharge valve.
• a patent which illustrates the third type of prior art barrier pack is U.S. Patent No. 3,109,463.
• a problem with the piston-type barrier pack of the first type is the imperfect seal between the side skirt of the piston and the side wall of the container which allows propellant to seep into the product with consequent discharge of propellant during product discharge as well as contamination of the product with propellant. Also, it is not uncommon for aerosol containers to be dented and thus lose their true circumferential shape, with the consequence that the piston is incapable of axial movement within the containe past the aberrant configuration.
• barrier packs of the second type wherei the barrier is affixed to the valve or valve opening of th container is that the barrier collapses in a manner to caus pocketing of the product within the collapsible barrier wit consequent undesirable diminution of the evacuation of th product from the container.
• the unfolding cup-shape barrier does not advanc progressively and uniformly against the inner wall of th container but tends to pocket and entrap product against th wall or within pockets formed in the barrier itself as i unfolds .
• Attempts to solve these problems have include adding an additional rigid piston to the end-closing portio of the inner wall, or adhering the outer wall of the barrie in peelable fashion to the inner wall of the container.
• barriers of the third type can be difficult t form, as well as to insert into and seal with the container.
• the present invention relates to an improvement in the third type of barrier pack.
• the present invention concerns a unitary flexible and expandable barrier for use in a plural-zoned, valved pressure container wherein the barrier has a shaped spatial form having sufficient rigidity to maintain its shape prior to insertion into and use in a plural-zoned, valved pressure container.
• the barrier comprises a flexible and expandable wall portion having an outer wall segment and an inner wall segment connected by an angled fold, the free terminal end of the outer wall segment forming a sealing means and the terminus of the inner wall segment distal to the fold extending into a central piston region that closes the barrier.
• the outer wall segment is steeply frustoconical in shape and terminates at its free end in a sealing means
• the inner wall segment is disposed in juxtaposed relation to the inner surface of the outer wall and in steeply frustoconical shape opposite to the frustoconical shape of the outer wall segment so as to form a small acute angle between the outer wall segment and the inner wall segment; the terminus of the inner wall segment distal to the fold being closed by a central piston region to thereby complete the unitary barrier member.
• the inner wall segment is sufficiently flexible to permit the inner wall segment and said central piston region to move in an axially downward direction under the influence of product pressure when the barrier is top sealed within a container, to assume a more or less phallic configuration.
• outer and inner wal segments have sufficient flexibility and expandability t extend outwardly under the influence of product pressure t substantially conform to the inner surface of the container
• product pressure t substantially conform to the inner surface of the container
• the outer wall segment wil tend to continue to substantially conform to the inner surfac of the container, and the flexible inner wall segment wil invert within the outer wall segment under the influence o propellant pressure to substantially return the barrier t approximately its shape as initially disposed in th container. Thereafter, the inner wall segment and centra piston area will stretch radially outwardly and upwardly t substantially evacuate the product in the container.
• the barrier of th present invention is very easily insertable into the top o the container.
• the barrier is nestable with like barriers fo convenience and cost savings in shipping. Further, th nesting facilitates fast and simple machine feeding of stacked barriers sequentially into the containers.
• the outer wall segment is thicker and more rigid than the inner wall segment; the inner wall segment also is of slightly less length than the outer wall segment; and the sealing means is a radially extending flange which acts as a gasket between the top of the sidewall of the container and the top closure of the container.
• the central piston region also may be thicker than the inner wall segment.
• a particularly advantageous material for barriers is polyethylene terephthalate (PET) .
• PET polyethylene terephthalate
• the barrier of the present invention may utilize a unitary multi-layer configuration. Such multi-layer configurations, their materials of construction and their manufacture, are well known to those skilled in the art.
• the inner layer is a material that prevents transport of propellant and product therethrough and the outer layers are inert to the propellant and product.
• Figure 1 is an elevational cross-sectional view of an embodiment of the barrier of this invention.
• Figure 2 is an elevational cross-sectional view of the barrier of Figure 1 positioned within an empty aerosol container with the top opening of the container shown in schematic and the aerosol valve not shown.
• Figure 3 is a schematic view of the barrier of thi invention within an aerosol container showing the barrier i a position after loading of the product into the container bu prior to introducing propellant to the container.
• Figure 4 is a schematic view of the barrier of thi invention within an aerosol container after the product ha been partially evacuated from the container.
• Figure 5 is a schematic view of the barrier of thi invention within an aerosol container after the product has been further evacuated and the barrier has inverted to the shape as initially present in the aerosol container, als showing in dotted-line a full evacuation of product.
• Figure 6 is a partial cross-sectional view of a multilayered barrier of the present invention.
• Figure 7 shows barriers of this invention in a nesting relation.
• Figure 8 is a schematic diagram of the several steps used in fabricating the barrier pack of this invention from a plastic sheet.
• Figure 9 is a schematic of the thermoforming equipment used in forming the barrier pack of this invention.
• Figure 1 shows a unitary barrier generally designated at 10, as it is initially formed, said barrier having a wall 11 comprising a flexible and expandable outer wall segment 12 and a flexible and expandable inner wall segment 14 connected by a fold 15, the outer wall segment 12 terminating in a sealing flange 16.
• central piston region 20 extends inwardly to close the barrier.
• the outer wall segment 12 has a steeply frusto-conical shape extending from the sealing flange 16 to the fold 15, and that the inner wall segment 14 has a steeply frustoconical shape oppositely directed to the outer wall segment 12 extending from the fold 15 to the central piston region 20.
• Container used with aforedescribed PET barrier was a 202 x 509 straight sided can which is 2 1/8" in diameter and 5 9/16" in length.
• the barrier had a 1° taper to each of the outer and inner wal segments, 12 and 14, respectively, to form a fold 15 providin an included angle of 2° between the outer and inner wal segments, 12 and 14. It is believed that a 3° taper to eac of the inner and outer wall segments will also functiono satisfactorily.
• the central piston region for th above-described barrier had a configuration as shown in Figur 1, wherein the terminus 18 at the perimeter of the piston ha a depth of 0.188" and a radius of .063".
• the sealing flang 16 for the described barrier had a turning radius into oute wall segment 12 of .078".
• Figure 2 shows the barrier 10 inserted in a valve pressure container, generally designated as 22, having inne wall surface 23, and permanently joined to the container 2 through the sealing flange 16 by an appropriate crimping o the flange 16 between the joint formed by the upper end 25 o the sidewall of the container 22 and the perimeter of th upper closure 27 of the container 22.
• a valve pressure container generally designated as 22
• a sealable port 28 is provided in the botto closure 26 for introduction of propellant.
• a manuall actuable valve (not shown) is positioned in a manner well known to those skilled in the art in the opening 29 of the pressure container 22.
• the barrier 10 divides the interior of the container 22 into a plural zoned pressure container; the upper zone 33 for receiving the product to be dispensed and the lower zone 35 for receiving the propellant.
• the container manufacturer will insert the barrier 10 into container 22, and seal the barrier to the container as described above.
• a product filler will thereafter fill the product and propellant into the respective chambers 33 and 35.
• Figure 2 shows a configuration for annexing the barrier 10 to the container 22.
• Figure 2 shows the barrier pack 10 having a terminal flange 16 extending from the outer wall segment 12.
• the flange 16 fits tightly between the flanges 25 and 27.
• the seam is formed by rolling the flanges 25, 27 and 16 toward the side wall 12 to form a rolled seam by techniques known to those skilled in the art.
• the thickness and lengt of the sealing flange 16 is dictated by the requirements o rolled seams, which may vary by type of container and rollin equipment.
• the sealing flange 16 may be thicker than th contiguous outer wall segment 12.
• the sealing flange 16 ma function as a gasket in sealing the barrier to the base of th container. If necessary, an adhesive may be provided to th components that are to be roll seamed.
• Figure 3 shows the barrier in an initial position a shor period of time after loading the container with product.
• product Upo continuous or intermittent actuation of the valve disposed i the top opening of the pressurized container, product will b evacuated from the container by lowering the pressure in th product zone 33 and causing the greater pressure in th propellant zone 35 to begin to invert the inner wall 14 of th barrier 10 within the outer wall 12 and thereby force th product through the discharge valve of the container.
• a product is evacuated from the container 22, the inner wal segment 14 and the central piston region 20 move axiall toward the aerosol discharge valve as the barrier inverts, a shown in Fig. 4.
• the outer wall segment 12 has a sufficient thicknes throughout from the terminal flange 16 to the fold 15, the outer wall segment will continue to substantially confor to the inner surface 23 of the container wall throughout th product evacuation shown schematically in Figures 4 and 5
• the barrier then returns to approximately its initial shape a shown in Fig. 5, followed by radial and axial stretching o inner wall segment 14 and central piston region 20 to the dotted line configuration shown in Fig. 5 to obtain substantially complete product evacuation from the container.
• the thickness of outer wall segment 12 likely will need to be substantially greater than the .007" thickness referenced above,* without wishing to in any way be limited, the thickness may be of the order of .020" to .025" from flange 16 to fold 15, or sufficient to obtain the full inversion of the inner wall segment within the outer wall segment shown in Fig. 5. With this thicker outer wall segment more viscous products may be fully evacuated from the container without significant pocketing. The inner wall segment will still remain thin and flexible.
• the transition from Fig. 4 to nearly complete product evacuation will result in both inner and outer wall segments 12 and 14 crumpling inwardly and tightly together, and moving upwardly.
• substantially complete product evacuation was obtained from a test set-up without significant pocketing. Where more viscous products are used, however, it is expected that the thicker outer wall segment 12 will need to be utilized to obtain the full product evacuation without significant pocketing.
• the frustoconical configuration of the inner wall segment 14 results in the inner wall segment 14 progressively inverting in an axial direction within the outer wall segment 12, where outer wall segment 12 is sufficiently thick, to cause the progressive advance of th product to the discharge valve and a minimization of th capture or entrapment of product in pockets.
• the tapering of the outer wall segment facilitates th invagination of the barrier of the present invention into th pressurized container.
• the presence of the tapering of bot the outer and inner wall segments, and at small angles, als allows maximum nesting of the barriers for convenience an cost savings in shipping the barriers from a manufacturin site to the site of the container manufacturing operation.
• a the container manufacturing site, the stacks of neste barriers facilitate fast and easy feeding of the barrier sequentially into the containers.
• Each nested barrier may b pulled from its stack into its intended container under th influence of an initial vacuum in the container shell, eac barrier as it is inserted into its container shutting off th vacuum; alternatively each nested barrier may be blown by ai from its stack into the intended container.
• nex container shell is fed under the stack of nested barriers, an the identical action continues for the next container and nex barrier.
• Containers continue to be sequentially fed under th nested stacks of barriers, and the nesting provides for a hig speed and very simple feeding operation.
• the flexible barrier in accordance with th present invention is optionally made of a multilayere material.
• Figure 6 shows a wall construction consisting of a inner layer 102 designed to prevent transport of propellant and product. Layer 102 is sandwiched between outer layers 104 and 106 that are inert to propellant or product in contact with the outer layers. Adhesive layers 108 and 110 are optionally provided, or alternatively the inner and outer layers 102, 104 and 106 may be fused together by heat or other means.
• the inner layer 102 is a gas barrier layer and the outer layers 104 and 106 are aqueous or organic fluid barrier layers.
• the gas barrier layer may be made of PET, ethylene vinyl alcohol, polyvinylalcohol, polyvinylidene chloride, polyacrylonitrile, cellophane or other similarly suitable materials.
• the outer layers may be made of PET, polyethylene, (especially high density polyethylene) polypropylene, polytetrafluoroethylene, polybutane, surlyn ionomer, butyl rubber, polyvinylidene chloride, polychlorotrifluoroethylene , Penton, polyvinylfluoride or other similarly suitable materials.
• Ethylene vinyl alcohol and polyvinyl alcohol are preferred gas barrier materials and high density polyethylene is a preferred aqueous or organic fluid barrier material.
• any propellants known in the art may be used with the dispenser and flexible barrier of the present invention.
• the barrier of the present invention requires smaller amounts of liquified propellants than required in non-barrier pack aerosol systems and in certain barrier pack systems using compressed gases, thus allowing the economic use of more expensive propellants.
• the present system lends itself to a maximization of the amount of product to be dispensed from given container.
• thermoforming The barrier pack of this invention as described at page 9 and 10 hereof is presently manufactured utilizing a formin process generally referred to as thermoforming.
• Th thermoforming technique for manufacturing plastic shapes fro a sheet of the plastic material is well-known in a genera sense. Specific modifications of the general techniques ar used to tailor the thermoforming process to the forming of particular shape.
• the schematic diagram of Figure 8 show the several steps involved in the forming of the barrier pack of this invention.
• step 1 the plastic sheet material PET, for example, having a thickness of .025", is passed through a dry heat zone (oven) to bring the PET to a formin temperature of 250°-330°F.
• the PET material found suitable for forming th barrier packs is biaxially oriented and suitable for deep dra thermoforming.
• the barrier pack of this invention is a deep drawn par and thus is susceptible to "webbing", i.e. the formation of fold of excess material at the mold base and the barrier sid wall. Where "webbing" is a concern, careful control of th temperature of the plastic sheet material is critical Moreover, with temperature control and avoidance of temperature above the distortion temperature of the plasti sheet material, a degree of plastic memory is retained by th plastic material, this memory aiding in the preclusion or removal of the "webbing" problem.
• step 2 the pre-heated PET sheet is moved to the forming station (thermoformer) , whereat the PET sheet is prestretched using a "plug assist" for the initial forming of the inner wall segment and the piston region of the barrier pack and using a “ring” to partially form the outer wall segment. Also see Figure 9.
• the “ring” assists in the avoidance of "webbing".
• the "plug assist” and “ring” are mounted on the upper movable platen (top base plate) of the thermoformer equipment, directly across from the lower movable platen (base plate) on which the mold is mounted. After disposing the heated plastic sheet between the upper and lower platens, the forming operation is commenced by moving the platens toward each other to sandwich the heated sheet.
• the "plug assist” and “ring” draw the sheet into and around the interior cavity surface of the mold to force the heated PET sheet to conform and contact the mold at the fold joining the outer wall segment and the inner wall segment and at the base of the "ring".
• the "ring” in forcing the PET plastic sheet against the base plate of the thermoforming equipment effects an annular seal around the mold. After effecting the seal, vacuum is applied to the mold to cause the PET plastic sheet to be drawn against the mold surface and thereby complete the final shaping of the PET plastic sheet.
• the mold is water cooled, teflon coated aluminum, hea conductive, and the "plug assist" and “ring” are fine-graine wood covered with felt to avoid scuffing and sticking of th formed part .
• the upper and lower platens ar separated and the formed sheet transported to the trimmin station (step 3) whereat cutting dies trim the formed parts.
• the formed parts are ejected to a stacker and the trimme residue at the sealing flange is ground for recycling an reclaiming in the plastic sheet extrusion process.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Containers And Packaging Bodies Having A Special Means To Remove Contents (AREA)
• Nozzles (AREA)

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• 1995
  • 1995-07-19 CA CA002195405A patent/CA2195405A1/en not_active Abandoned
  • 1995-07-19 JP JP8505286A patent/JPH10502893A/ja not_active Ceased
  • 1995-07-19 NZ NZ291562A patent/NZ291562A/xx unknown
  • 1995-07-19 RU RU97102351A patent/RU2142901C1/ru active
  • 1995-07-19 EP EP95929351A patent/EP0771294A4/en not_active Withdrawn
  • 1995-07-19 WO PCT/US1995/009734 patent/WO1996002439A1/en not_active Application Discontinuation
  • 1995-07-19 CN CN95194955A patent/CN1157603A/zh active Pending
  • 1995-07-19 AU AU32734/95A patent/AU709138B2/en not_active Ceased
  • 1995-07-19 BR BR9508317A patent/BR9508317A/pt not_active Application Discontinuation
  • 1995-07-19 PL PL95318170A patent/PL179040B3/pl unknown
  • 1995-07-19 ZA ZA956019A patent/ZA956019B/xx unknown
• 1997
  • 1997-01-15 NO NO970179A patent/NO970179L/no not_active Application Discontinuation
  • 1997-01-17 FI FI970220A patent/FI970220A7/fi unknown
  • 1997-01-18 KR KR19977000348A patent/KR970704614A/ko not_active Withdrawn

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