Die, system, and method for coextruding a plurality of fluid layers

• US 20100072655A1
• Filed: 09/23/2008
• Published: 03/25/2010
• Est. Priority Date: 09/23/2008
• Status: Abandoned Application

• Current Assignee: Cryovac Incorporated (Sealed Air)
• Original Assignee: Cryovac Incorporated (Sealed Air)
• Inventors: Roberts, Lawrence E., Webster, Bradford E., Timmons, Anton L.
• Application Number:
  US12/284,510
• Publication Number:
  US 20100072655A1
• Time in Patent Office: Days
• US Class Current: 264/171.130
• CPC Class Codes: B29C 2791/007 Using fluid under pressure
• CPC Class Codes: B29C 48/0018 combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/0019 combined with shaping by flattening, folding or bending
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 48/1472 at the die nozzle exit zone
• CPC Class Codes: B29C 48/18 the components being layers
• CPC Class Codes: B29C 48/185 comprising six or more components, i.e. each component being counted once for each time it is present, e.g. in a layer
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 48/304 specially adapted for bringing together components, e.g. melts within the die
• CPC Class Codes: B29C 48/307 specially adapted for bringing together components, e.g. melts within the die
• CPC Class Codes: B29C 48/32 with annular openings, e.g. for forming tubular articles
• CPC Class Codes: B29C 48/3363 using a layered die, e.g. stacked discs
• CPC Class Codes: B29C 48/49 using two or more extruders to feed one die or nozzle
• CPC Class Codes: B29D 23/00 Producing tubular articles B29D24/00 takes precedence
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/0608 characterised by its density
• CPC Class Codes: B29K 2023/0616 VLDPE, i.e. very low density polyethylene
• CPC Class Codes: B29K 2023/0625 LLDPE, i.e. linear low density polyethylene
• CPC Class Codes: B29K 2023/0633 : LDPE, i.e. low density polyethylene
• CPC Class Codes: B29K 2023/0641 : MDPE, i.e. medium density polyethylene
• CPC Class Codes: B29K 2023/065 : HDPE, i.e. high density polyethylene
• CPC Class Codes: B29K 2023/083 : EVA, i.e. ethylene vinyl acetate copolymer
• CPC Class Codes: B29K 2023/086 : EVOH, i.e. ethylene vinyl alcohol copolymer
• CPC Class Codes: B29K 2023/12 : PP, i.e. polypropylene
• CPC Class Codes: B29K 2025/00 : Use of polymers of vinyl-aromatic compounds or derivatives thereof as moulding material
• CPC Class Codes: B29K 2067/00 : Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2077/00 : Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material

Abstract

A die for coextruding a plurality of fluid layers generally includes a primary forming stem, one or more distribution plates, and a microlayer assembly. The microlayer assembly includes a microlayer forming stem and a plurality of microlayer distribution plates.

Claims

1. A die for coextruding a plurality of fluid layers, comprising:

a. a primary forming stem;

b. one or more distribution plates, each of said plates having a fluid inlet and a fluid outlet, the fluid outlet from each of said plates being in fluid communication with said primary forming stem and structured to deposit a layer of fluid onto said primary forming stem; and

c. a microlayer assembly, comprising

(1) a microlayer forming stem, and

(2) a plurality of microlayer distribution plates, each of said microlayer plates having a fluid inlet and a fluid outlet, the fluid outlet from each of said microlayer plates being in fluid communication with said microlayer forming stem and structured to deposit a microlayer of fluid onto said microlayer forming stem, said microlayer plates being arranged to provide a predetermined order in which the microlayers are deposited onto said microlayer forming stem to form a substantially unified, microlayered fluid mass on said microlayer forming stem,

wherein, said microlayer forming stem is in fluid communication with said primary forming stem such that said microlayered fluid mass flows from said microlayer forming stem and onto said primary forming stem.

2. The die of claim 1, wherein said distribution plates have a thickness ranging from about 0.5 to about 2 inches and said microlayer distribution plates have a thickness ranging from about 0.1 to about 0.5 inch.

3. The die of claim 1, wherein said microlayer distribution plates have one or more flow channels connecting said fluid inlet with said fluid outlet, said flow channels having a spiral-shaped configuration.

4. The die of claim 1, wherein

said microlayer distribution plates each have an orifice extending through said plate;

said fluid outlet of each of said microlayer distribution plates is positioned adjacent to said orifice; and

said microlayer forming stem extends through the orifice of each of said microlayer distribution plates.

5. The die of claim 1, wherein said primary forming stem and said microlayer forming stem are substantially coaxially aligned with one another.

6. The die of claim 5, wherein said microlayer forming stem is external to said primary forming stem.

7. The die of claim 1, wherein

said distribution plates and said microlayer assembly are axially positioned along said primary forming stem;

and

the fluids from said distribution plates and said microlayer assembly flow in an axial direction along said primary forming stem.

8. The die of claim 7, wherein said distribution plates are located upstream of said microlayer assembly.

9. The die of claim 7, wherein said microlayer assembly is located upstream of said distribution plates.

10. The die of claim 7, wherein said microlayer assembly is positioned between one or more upstream distribution plates and one or more downstream distribution plates.

11. The die of claim 1, wherein said microlayer assembly comprises at least about 5 microlayer plates.

12. The die of claim 1, further including one or more additional microlayer assemblies.

13. A system for coextruding a plurality of fluid layers, comprising:

a. a die, comprising;

(1) a primary forming stem,

(2) one or more distribution plates, each of said plates having a fluid inlet and a fluid outlet, the fluid outlet from each of said plates being in fluid communication with said primary forming stem and structured to deposit a layer of fluid onto said primary forming stem, and

(3) a microlayer assembly, comprising

(a) a microlayer forming stem, and

(b) a plurality of microlayer distribution plates, each of said microlayer plates having a fluid inlet and a fluid outlet, the fluid outlet from each of said microlayer plates being in fluid communication with said microlayer forming stem and structured to deposit a microlayer of fluid onto said microlayer forming stem, said microlayer plates being arranged to provide a predetermined order in which the microlayers are deposited onto said microlayer forming stem to form a substantially unified, microlayered fluid mass on said microlayer forming stem, wherein, said microlayer forming stem is in fluid communication with said primary forming stem such that said microlayered fluid mass flows from said microlayer forming stem and onto said primary forming stem; and

b. one or more extruders in fluid communication with said die to supply one or more fluids to said die.

14. A method of coextruding a plurality of fluid layers, comprising:

a. directing a fluid through a distribution plate and onto a primary forming stem, said distribution plate having a fluid inlet and a fluid outlet, the fluid outlet from said plate being in fluid communication with said primary forming stem and structured such that said fluid is deposited onto said primary forming stem as a layer;

b. forming a substantially unified, microlayered fluid mass on a microlayer forming stem by directing at least one additional fluid through a microlayer assembly, said microlayer assembly comprising a plurality of microlayer distribution plates, each of said microlayer plates having a fluid inlet and a fluid outlet, the fluid outlet from each of said microlayer plates being in fluid communication with said microlayer forming stem and structured to deposit a microlayer of fluid onto said microlayer forming stem, said microlayer plates being arranged to provide a predetermined order in which the microlayers are deposited onto said microlayer forming stem; and

c. directing said microlayered fluid mass from said microlayer forming stem and onto said primary forming stem to merge said microlayered fluid mass with said fluid layer from said distribution plate.

15. The method of claim 14, wherein the fluid directed through said distribution plate is substantially the same as the fluid directed through said microlayer assembly.

16. The method of claim 14, wherein the fluid directed through said distribution plate is different from the fluid directed through said microlayer assembly.

17. The method of claim 14, wherein said fluid layer from said distribution plate is deposited onto said primary forming stem prior to the deposition of said microlayered fluid mass onto said primary forming stem such that said fluid layer from said distribution plate is interposed between said microlayered fluid mass and said primary forming stem.

18. The method of claim 14, wherein said microlayered fluid mass is deposited onto said primary forming stem prior to the deposition of said fluid layer from said distribution plate onto said primary forming stem such that said microlayered fluid mass is interposed between said fluid layer from said distribution plate and said primary forming stem.

19. The method of claim 14, wherein:

each of said microlayers has a thickness M,

said fluid layer from said distribution plate has a thickness D, and

the ratio of M;

D ranges from about 1;

1 to about 1;

8.