Preparation of conductive polyurethanes using a conductive quasi-solution

• US 6,111,051 A
• Filed: 08/07/1998
• Issued: 08/29/2000
• Est. Priority Date: 08/07/1998
• Status: Expired due to Term

• Current Assignee: Fleet National Bank (Bank of America Corp.)
• Original Assignee: Mearthane Products Corporation
• Inventors: Chiang, Albert C., Roderick, John A.
• Primary Examiner(s): Truong, Duc
• Application Number:
  US09/130,946
• Time in Patent Office: 753 Days
• Field of Search: 528/71, 528/76, 528/56, 528/59, 528/61, 528/65, 528/85, 524/589, 524/590, 521/65, 521/67, 521/134, 521/137, 521/155, 521/159, 521/911, 264/45.9, 264/46.8
• US Class Current: 528/71
• CPC Class Codes: C08G 18/08 Processes
• CPC Class Codes: C08G 2120/00 Compositions for reaction injection moulding processes
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: H01B 1/122 Ionic conductors
• CPC Class Codes: Y10S 521/911 Surfactant for other than polyurethane cellular product

Abstract

A conductive quasi-solution useful for making a homogeneously conductive single-phase polyurethane, comprising a transition metal salt, a carrier solution, and a dispersing agent, wherein said conductive quasi-solution has a transition metal salt concentration between 10 and 30% by weight, and methods of making thermoset and thermoplastic polyurethane polymers therewith.

Claims

1. A method of making a homogeneously conductive single-phase thermoplastic polyurethane, comprising

mixing, with heating, a combination containing a transition metal salt, a dispersing agent, and a solvent comprising a flame retardant, a polyol, or a polyamine to provide a conductive quasi-solution having undissolved particles of said transition metal salt in said solvent, and

combining said conductive quasi-solution with a thermoplastic polyurethane precursor and a diisocyanate to provide a homogeneously conductive single-phase thermoplastic polyurethane containing said transition metal salt.

2. The method of claim 1, wherein said transition metal salt comprises a transition metal selected from Cu (II), Fe (III), Ni (II), Zn (II), and Co (II), and a counter-anion selected from acetate, tartrate, lactate, phosphate, oxalate, fluoride, chloride, bromide, iodide, thiocyanate, and cyanide.

3. The method of claim 2, wherein said transition metal salt comprises Fe (III) or Cu (II).

4. The method of claim 2, wherein said transition metal is Cu (II) or Fe (III), and said counter-anions are independently selected from acetate, thiocyanate, chloride, or bromide.

5. The method of claim 1, wherein there are at least two transition metal salts in said conductive quasi-solution.

6. The method of claim 5, wherein said transition metal salts comprise Fe (III) and Cu (II).

7. The method of claim 5, wherein said transition metal salt comprises copper chloride.

8. The method of claim 1, wherein said combination contains between 10% and 30% by weight of said transition metal salt.

9. The method of claim 1, wherein said combination contains between 15% and 25% by weight of said transition metal salt.

10. The method of claim 1, wherein said dispersing agent comprises a non-ionic surfactant.

11. The method of claim 1, wherein the concentration of said dispersing agent in said conductive quasi-solution is between 0.5% and 5% by weight.

12. The method of claim 1, wherein the concentration of said dispersing agent in said conductive quasi-solution is between 1% and 3% by weight.

13. The method of claim 1, wherein said solvent comprises a flame retardant comprising a phosphate haloalkyl ester or a diphosphate haloalkyl ester.

14. The method of claim 1, wherein said solvent comprises a polyol.

15. The method of claim 1, wherein said solvent comprises a polyamine.

16. The method of claim 1, wherein said solvent comprises a combination of a polyol and a polyamine.

17. The method of claim 1, wherein said combining step includes

combining said conductive quasi-solution with a thermoplastic polyurethane precursor to provide a conductive thermoplastic polyurethane precursor, and

combining a first stream comprising said conductive thermoplastic polyurethane precursor and a second stream comprising said diisocyanate to provide the homogeneously conductive single-phase thermoplastic polyurethane.

18. The method of claim 17, wherein said transition metal salt is fully dissolved in said conductive thermoplastic polyurethane precursor.

19. The method of claim 17, wherein said quasi-solution in said conductive thermoplastic polyurethane precursor is about 0.1 to 10% by weight.

20. The method of claim 17, wherein said first stream is combined with said second stream at a temperature between 100 and 240°

F.

21. The method of claim 1, further comprising postcuring the thermoplastic polyurethane after the combining step.

22. The method of claim 17, wherein said conductive thermoplastic polyurethane precursor contains an amine catalyst, a tin catalyst, or a bismuth catalyst.

23. The method of claim 22, wherein said catalyst is between 0.01 and 0.5% by weight with respect to the total amount of said thermoplastic polyurethane precursor.

24. The method of claim 22, wherein said catalyst is between 0.02 and 0.3% by weight with respect to the total amount of said thermoplastic polyurethane precursor.

25. The method of claim 1, wherein said homogeneously conductive single-phase thermoplastic polyurethane contains between 0.02% and 1% of the transition metal salt by weight.

26. The method of claim 1, wherein said homogeneously conductive single-phase thermoplastic polyurethane contains between 0.04% and 0.2% of said transition metal salt by weight.

27. The method of claim 1, wherein said undissolved particles have a maximum diameter of from about 0.1 μ

m to about 0.5 μ

m.