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
  • B29C51/14—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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/07—Flat, e.g. panels
  • B29C48/08—Flat, e.g. panels flexible, e.g. films
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
  • B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/30—Extrusion nozzles or dies
  • B29C48/305—Extrusion nozzles or dies having a wide opening, e.g. for forming sheets
  • B29C48/307—Extrusion nozzles or dies having a wide opening, e.g. for forming sheets specially adapted for bringing together components, e.g. melts within the die
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/07—Flat, e.g. panels

Definitions

• the invention relates to preparing objects thermoformed from p astic sheets.
• Plastic sheets are often produced by appara ⁇ tus in which plastic material is heated and sup ⁇ plied under pressure to an extrusion die. The sheets can then be thermoformed to a desired shape, and individual objects can be trimmed from the thermoformed sheet.
• the invention features coextruding a multilayered sheet having adjacent layers of plastics that do not bond to each other during co ⁇ extrusion, thermoforming the multilayered sheet, and separating individual thermoformed objects of different layers.
• the produc ⁇ tivity of the extrusion, thermoforming, and trim ⁇ ming apparatus is multiplied by the number of layers in the sheet.
• one of the plastics in the multilayered sheet is polystyrene and another plastic is polypropylene; in some preferred embodiments one plastic is for a separator layer between plastic layers for the thermoformed objects, and in other preferred embodiments the thermoformed objects are made from more than one of the plastics of the layers of the multilayered sheet.
• the thermoforming of the multilayered sheet with poly ⁇ propylene and polystyrene layers is faster. than the slow, and therefore expensive, thermoforming of polypropylene alone- Description of the Preferred Embodiment
• draw ⁇ ing is a diagrammatic view of a process of manufacturing plastic objects according to the in ⁇ vention.
• Two heated containers 16, 18 serve as sources of the polystyrene (70% crystal styrene and ' 30% rub ⁇ ber modifying plastomer sold by Phillips Chemical Company under the trade designation Solprene 416P, a block polymer having a butadiene/styrene ratio of 70/30, a molecular weight of 140 M, a density of 0.94, and a melt flow index of 2 decigrams/ in) , and polypropylene- (available from Rexene Company, Paramus, New Jersey, and having a meltr flow index of 4 decigrams/ in) , respectively.
• Solprene 416P a block polymer having a butadiene/styrene ratio of 70/30, a molecular weight of 140 M, a density of 0.94, and a melt flow index of 2 decigrams/ in)
• polypropylene- available from Rexene Company, Paramus, New Jersey, and having a meltr flow index of 4 decigrams/
• Conduits 20, 22, 24, 26, 28 supply the heated materials to coextrusion block ' 30. There the ma ⁇ terials merge together to form under pressure a unitary, five-layer thick stream ' 32 of generally circular cross section. Stream ' 32 passes into extrusion die ' 34 "(e.g. , Welex standard 54" flex- lip die) for extrusion into continuous sheet ' 36. Sheet ' 36 then passes through a series of chill rolls 38.
• extrusion die ' 34 "(e.g. , Welex standard 54" flex- lip die)
• the sheet after coextrusion, may then be thermoformed into bowls or wound into spools (not shown) for storage and later themoforming.
• thermoforming apparatus 40 the vacuum forming type well known in the art
• the shaped sheet 42 passes through trim press 44, in which the indivi ⁇ dual bowls 12 and 14 are trimmed. Because the polypropylene and polystyrene of bowls 12, 14, respectively, do not bond to each other during coextrusion or thermoforming, bowls 12, 14 can be easily separated from each other.
• the simultaneous coextruding of five sheets and thermoforming and trimming of five bowls act to increase the produc ⁇ tivity of the coextrusion, thermoforming, and trimming apparatus. by a factor of five. Also, the thermoforming of the five-layer sheet is faster than the slow, and therefore expensive, thermoform ⁇ ing of polypropylene alone.
• plastics that do not bond to each other can be used in place of the polystyrene and polypropy ⁇ lene.
• one of the plastic layers could be a thin separator layer which would be used for scrap after separating the thermoformed objects from each other.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Laminated Bodies (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=23357183

Family Applications (1)

Country Status (3)

Families Citing this family (6)

Family Cites Families (7)

• 1983
  • 1983-02-04 CA CA000420898A patent/CA1198562A/en not_active Expired
  • 1983-02-04 EP EP83901009A patent/EP0101500A1/de not_active Withdrawn
  • 1983-02-04 WO PCT/US1983/000158 patent/WO1983002747A1/en not_active Ceased

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events