Microlayer Structures and Methods

• US 20080254281A1
• Filed: 10/20/2005
• Published: 10/16/2008
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Chen, Hongyu, Wevers, Ronald, McLeod, David G.
• Granted Patent: US 8,043,696 B2
• Time in Patent Office: Days
• US Class Current: 428/335
• CPC Class Codes: B29C 2043/3602 with means for positioning, fastening or clamping the material to be formed or preforms inside the mould
• CPC Class Codes: B29C 2043/3631 moving in a frame for pressing and stretching; material being subjected to compressing stretching
• CPC Class Codes: B29C 43/36 Moulds for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B29C 51/004 Textile or other fibrous material made from plastics fibres combined with plastic layers B29C51/145; compression moulding of reinforced plastic articles in matched moulds B29C70/46; using pressure difference B29C70/44
• CPC Class Codes: B29C 70/04 comprising reinforcements only, e.g. self-reinforcing plastics
• CPC Class Codes: B29K 2023/0641 MDPE, i.e. medium density polyethylene
• CPC Class Codes: B29K 2023/12 PP, i.e. polypropylene
• CPC Class Codes: B32B 1/00 Layered products having a non-planar shape
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: D03D 15/283 synthetic polymer-based, e.g. polyamide or polyester fibres cellulose-based artificial fibres D03D15/225
• CPC Class Codes: D03D 15/46 Flat yarns, e.g. tapes or films
• CPC Class Codes: D10B 2321/021 polyethylene
• CPC Class Codes: D10B 2321/022 polypropylene
• CPC Class Codes: D10B 2401/041 thermoplastic; thermosetting
• CPC Class Codes: D10B 2505/02 Reinforcing materials; Prepregs
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1303 Paper containing [e.g., paperboard, cardboard, fiberboard, etc.]
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/1359 Three or more layers [continuous layer]
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 : Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 : Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24975 : No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/264 : Up to 3 mils
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31909 : Next to second addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31913 : Monoolefin polymer
• CPC Class Codes: Y10T 442/2008 : Fabric composed of a fiber or strand which is of specific structural definition

Abstract

Improved microlayer structures and methods typically employing at least 4 stacked layers of polymers (e.g., including alternating layers of components A and B), such as that obtained by coextrusion. The layers each have a thickness of less than about 50 microns. One optional approach involves forming an intermediate form that includes at least one elongated member made from the plurality of layers, from which a shaped composite article may be made.

Claims

1. An elongated member, comprising:

at least 10 stacked and coextruded layers that each are continuous in profile and include a polyolefinic polymer, each layer having a thickness less than about 50 microns, and each layer differs relative to its adjoining layer in at least one characteristic selected from composition, degree of crystallization, molecular orientation, molecular weight, melt rate, peak melting temperature, glass transition peak, temperature of crystallization, seal initiation temperature, softening point, molecular weight distribution or any combination thereof, and wherein the member is capable of withstanding a draw ratio of greater than 18.

6. The elongated member of claim 1, wherein the polymers of at least two adjoining layers include propylene.

7. The elongated member of claim 1, wherein the polymers of at least two adjoining layers include ethylene.

10. The elongated member of claim 1, wherein the polymers of the at least two adjoining layers each have a peak melting temperature that differ by at least 5°

C.

11. The elongated member of claim 1, wherein the polymer of at least one of the layers has a melting point below 125°

C.

15. The elongated member of claim 1, further comprising an additive or other functional material.

16. The elongated member of claim 15, wherein the additive or other functional materials is a tie-in layer or an intermediate bonding agent layer between at least two of the stacked layers.

17. The elongated member of claim 16, wherein the tie-in layer or the intermediate bonding agent layer includes a polyolefin with a functional reactive group.

18. The elongated member of claim 17, wherein the tie-in layer or the intermediate bonding agent layer includes maleic anhydride-grafted polypropylene.

19. The elongated member of claim 1, further comprising a non-migratory processing or surface modification agent selected from silicones, a halogenated polymer, or a combination disposed on an exposed surface of at least one of the layers.

20. The elongated member of claim 19, wherein the non-migratory processing or surface modification agent is dimethylsiloxane.

21. The elongated member of claim 1, wherein the stacked layers are coextruded layers.

22. The elongated member of claim 1, wherein the microlayers are prepared from 2 different polymeric components, denoted A and B, and further wherein the structure of the assembly of microlayers is ((A-B)_n-A) where n is an integer of 2 or greater.

23. The elongated member of claim 1, wherein n is at least 10.

24. The elongated member of claim 1, wherein n is at least 100.

25. The elongated member of claim 1, wherein at least one layer includes a propylene-ethylene copolymer that exhibits a melt flow rate at 230°

C. per ASTM D1238 of 0.3 to 50 g/10 min;

a density per ASTM D792 of 0.858 to 0.888 g/cc;

an ethylene content of 5 to about 25 wt %;

a Melting Range from 50 to 135°

C.;

a Shore A Hardness from 40 to 90; and

a flexural modulus per ISO 178 of 10 to 280 MPa.

26. The elongated member of claim 1, wherein at least one layer includes a polypropylene homopolymer that exhibits a melt flow rate at 230°

C. per ASTM D1238 of less than 7 g/10 min;

a 1% secant flexural modulus of greater than 2000 MPa;

a crystallinity of at least 70%;

an isotactic pentad/triad ratio of greater than 85%; and

a peak melting temperature of greater than 160°

C.

27. The elongated member of claim 22, wherein the A component includes a propylene-ethylene copolymer that exhibits a melt flow rate at 230°

C. per ASTM D1238 of 0.3 to 50 g/10 min;

a density per ASTM D792 of 0.858 to 0.888 g/cc;

an ethylene content of 5 to 25 wt %;

a Melting Range from 50 to 135°

C.;

a Shore A Hardness from about 40 to about 90; and

a flexural modulus per ISO 178 of 10 to 280 MPa and the B component includes a polypropylene homopolymer that exhibits a melt flow rate at 230°

C. per ASTM D1238 of less than 7 g/10 min;

a 1% secant flexural modulus of greater than 2000 MPa;

a crystallinity of at least 70%;

an isotactic pentad/triad ratio of greater than 85%; and

a peak melting temperature of greater than 160°

C.

28. The elongated member of claim 27, further comprising a dimethylsiloxane agent disposed on an exposed surface of the elongated member.

29. The elongated member of claim 27, further comprising a tie-in layer or an intermediate bonding agent layer that includes maleic anhydride-grafted polypropylene disposed between at least one of the component A and component B layers.

2-5. -5. (canceled)

8-9. -9. (canceled)

12-14. -14. (canceled)

30-61. -61. (canceled)