Extrusion method forming an enhanced property metal polymer composite

• US 20060055077A1
• Filed: 11/12/2004
• Published: 03/16/2006
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Tundra Composites, LLC.
• Original Assignee: Tundra Composites, LLC.
• Inventors: Heikkila, Kurt E.
• Granted Patent: US 7,491,356 B2
• Time in Patent Office: Days
• US Class Current: 264/173.160
• CPC Class Codes: A01K 95/005 Sinkers not containing lead
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: B29L 2031/22 Hinges , pivots
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: F42B 12/745 the core being made of plastics; Compounds or blends of plastics and other materials, e.g. fillers
• CPC Class Codes: F42B 7/046 Pellets or shot therefor
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof

Abstract

The invention relates to an extrusion method and to an extrudable metal polymer composite having increased density, improved viscoelastic properties, malleability and ductility and thermoplastic extrusion or injection molding properties.

Claims

1. A method to extrude a metal polymer composite comprising:

(a) combining;

(i) a metal particulate, the metal having a density greater than 4 gm-cm<sup>−

3</sup>, the particulate comprising 5 wt-% or less of particles having a particle size of less than 10 microns, at least 5 wt.-% of the metal within a range of 10 to 70 microns, at least 5 wt.-% of the metal within a range of 70 to 250 microns, and an excluded volume of about 13 to about 60 volume-%; and

(ii) a polymer phase comprising a polymer in sufficient amounts to substantially occupy the excluded volume of the particulate to form a composite mix; and

(b) extruding the mix at a temperature greater than 100°

C. and at a shear rate of about 1 to 500 sec<sup>−

1</sup>;

wherein the extruded composite has a density greater than about 4 gm-cm³ the composite having a storage modulus of at least 300 MPa.

2. The method of claim 1 comprising extruding the mix at a temperature greater than 150°

C. and at a shear rate of about 10 to 300 sec<sup>−

1</sup>.

3. The method of claim 1 wherein the composition comprises about 0.005 to 3 wt-% of an interfacial modifier and the metal particulate is present in an amount of about 45 to 96 vol.-%.

4. The method of claim 1 wherein the polymer is a halogen containing polymer having a density of greater than 1.2 gm-cm⁻

3.

5. The method of claim 1 wherein the composite comprises an pigment.

6. The method of claim 1 wherein the composite comprises dye.

7. The method of claim 1 wherein the metal comprises a particulate having at least 5 wt.-% of the metal with particle size ranging greater than 250 microns.

8. The method of claim 4 wherein the polymer comprises a fluoroelastomer.

9. The method of claim 5 comprising extruding the mix at a temperature greater than 180°

C. and at a shear rate of about 5 to 500 sec<sup>−

1</sup>;

27. The method of claim 1, where the viscoelastic composition has significantly reduced wear characteristics.

28. The method of claim 1, further comprising coextruding the mix with a coextrudate comprising a polymer.

29. The method of claim 1, further comprising passing the mix through a shaped die to form a shaped composite.

30. The method of claim 29, wherein the shaped die comprises a shape that allows two shaped composite articles to interlock when pressed together.

10. A method to extrude a metal polymer composite, the composite comprising a metal particulate and a polymer phase, the method comprising:

(a) combining;

(i) about 96 to 45 volume-% of a metal particulate comprising 5 wt-% or less of particles having a particle size of less than 10 microns, the metal having a density greater than 8 gm-cm<sup>−

3</sup>, in a particulate phase having a particle size distribution having at least 10 wt.-% of particulate within of about 10 to 70 microns, at least 20 wt.-% of the polymer particulate within about 70 to 500 microns, a circularity greater than 13 and an aspect ratio less than 3;

(b) about 4 to 53 volume-% of a polymer phase;

(c) about 0.005 to 3 wt.-% of an interfacial modifier material to form a composite mix; and

(d) extruding the mix at a temperature greater than 100°

C. and at a shear rate of about 1 to 500 sec<sup>−

1</sup>;

wherein the extruded composite has a density is greater than about 7 gm-cm<sup>−

3</sup> and a storage modulus of greater than 300 MPa.

11. The method of claim 10 wherein the composite comprises a single polymer source and the interfacial modifier comprises about 0.005 to 0.7 wt.-% of the composite.

12. The method of claim 10 wherein the composite comprises polymer blend or alloy and the interfacial modifier comprises about 0.005 to 1 wt.-% of the composite

13. The method of claim 10 wherein the metal comprises tungsten and the polymer comprises a vinyl polymer.

14. The method of claim 10 wherein the metal particulate is present in an amount of about 50 to 85 volume-%.

15. The method of claim 10 wherein the polymer is a halogen containing polymer having a density of greater than 1.2 gm-cm⁻

3.

16. The method of claim 10 wherein the composite comprises a pigment.

17. The method of claim 10 wherein the composite comprises of dye.

18. The method of claim 10 wherein the metal has a density greater than 10 gm-cm⁻

3.

19. The method of claim 10 comprising extruding the mix at a temperature greater than 180°

C. and at a shear rate of about 5 to 500 sec<sup>−

1</sup>;

20. An injection molding process comprising heating a composite to an elevated temperature and injecting that composite into a mold;

wherein the composite comprises a polymer, and a metal particulate, the metal with a density greater than 7 gm-cm<sup>−

3</sup> and an interfacial modifier between 0.005 and 1 wt.-%.

21. A compression molding process comprising molding a composite under elevated pressure;

wherein the composite comprises a polymer, and metal particulate, the metal with a density greater than 7 gm-cm<sup>−

3</sup> and an interfacial modifier between 0.005 and 1 wt.-%.

22. A sequential compounding process comprising blending a polymer and metal particulate, the metal particulate having a density greater than 7 gm-cm⁻

3 and an interfacial modifier between 0.05 and 1 wt.-%.

23. A sequential compounding process comprising a first operation of blending a solvent-free mixture of a polymer, a metal particulate, the metal particulate having a density greater than 7 gm-cm⁻

3 and an interfacial modifier between 0.005 and 1 wt.-% to form a composite, and a second operation comprising compression molding, extrusion, or injection molding an object.

24. A sequential compounding process comprising a first operation of blending solvent, polymer, and metal particulate, the metal particulate having a density greater than 7 gm-cm⁻

3 and an interfacial modifier between 0.005 and 1 wt.-%, and a second operation comprising compression molding, extrusion or injection molding an object.

25. The method of claim 24 wherein the composite is formed by wetting the metal particulate with solvent and removing the solvent after processing

26. A sequential compounding process comprising blending solvent, polymer, metal particulate, the metal with a density greater than 7 gm-cm⁻

3 and an interfacial modifier between 0.005 and 1 wt.-%, followed by a solvent degassing of the composite during the melt portion of mixing.