CONDUCTIVE POLYURETHANE

Abstract

The present invention is directed to a polyol composition comprising carbon nanotubes and at least one carbon particle, polyurethane systems comprising said polyol composition, and polyurethanes, their preparation and use, in particular for filter casting. Also disclosed is a process for preparing a polyurethane such as by mixing a polyol composition and at least one polyisocyanate.

Claims

1. A polyol composition comprising: (i) at least one polyol having a functionality of ≥2.2; (ii) carbon nanotubes; and (iii) at least one carbon particle having a specific electrical resistance of ≤1Ω/cm measured according to IS 12178-1987 (Indian Standard).

2. The polyol composition according to claim 1, wherein component (i) comprises at least one polyester polyol and castor oil.

3. The polyol composition according to claim 1, wherein component (i) accounts for 40-99.7 wt. % based on the polyol composition.

4. The polyol composition according to claim 1, wherein the carbon nanotubes are single-walled carbon nanotubes (SWCNTs) and have an average outer diameter of 0.5-50 nm.

5. The polyol composition according to claim 1, wherein component (ii) accounts for 0.01-0.1 wt. % based on the polyol composition.

6. The polyol composition according to claim 1, wherein the carbon particles are substantially amorphous and are obtainable by combustion of acetylene in the presence of sub-stoichiometric amounts of oxygen.

7. The polyol composition according to claim 1, wherein component (iii) accounts for 0.2-4 wt. % based on the polyol composition.

8. The polyol composition according to claim 1, wherein the weight ratio of components (ii):(iii) is 1:75-1:3.

9. The polyol composition according to claim 1, further comprising at least one excipient.

10. A polyurethane system comprising: (a) a polyol composition according to claim 1; and (b) at least one polyisocyanate.

11. The polyurethane system according to claim 10, wherein the polyisocyanate is selected from aromatic or aliphatic polyisocyanate.

12. A process for preparing a polyurethane comprising the steps of: (I) providing the polyol composition according to claim 1; (II) providing at least one polyisocyanate; and (III) mixing the polyol composition and the at least one polyisocyanate.

13. A polyurethane obtainable by a process according to claim 12.

14. (canceled)

15. The polyol composition of claim 1, further comprising at least one filler.

16. The polyol composition according to claim 2, wherein component (i) further comprises at least one polyether polyol each having a functionality ≥2.2.

17. The polyurethane system according to claim 11, wherein the polyisocyanate is selected from MDI, oligomeric or polymeric MDI, TDI, HDI, IPDI, H.sub.12MDI or TMXDI and has an NCO content of ≥15%.

18. The process for preparing a polyurethane of claim 12, wherein the mixing is performed by adding a catalyst.

19. The process for preparing a polyurethane of claim 12, wherein the mixing is performed at an elevated temperature.

20. The polyol composition according to claim 9, wherein the at least one excipient comprises defoaming agents, wetting agents and dispersing agents and wherein the polyol composition further comprises a water scavenger.

Description

EXAMPLES

Example 1

[0067] 28.2 wt. % castor oil [0068] 30.8 wt. % glycerol started polyester polyol OHZ=400 mgKOH/g [0069] 0.5 wt. % dispersing additive [0070] 3.5 wt. % molecular sieve [0071] 0.5 wt. % nanotubes, predispersed [0072] 35 wt. % chalk [0073] 1.5 wt. % conductive carbon black, acetylene-based [0074] Cured with Desmodur 44V20 LF in the mixing ratio of 100:41 [0075] Index: 102

Physical Characteristics

[0076] Viscosity of polyol system (20° C.)=3900 mPas [0077] Hardness: Shore-D=79 [0078] Specific surface resistivity: 0.07 M Ω/cm [0079] Specific volume resistivity: 0.02 M Ω/cm

Example 2

[0080] 39.6 wt. % castor oil [0081] 29.4 wt. % castor oil-based polyester polyol with OHZ=160 mgKOH/g [0082] 0.5 wt. % dispersing additive [0083] 3.5 wt. % molecular sieve [0084] 0.5 wt. % nanotubes, predispersed [0085] 25 wt. % chalk [0086] 1.5 wt. % conductive carbon black, acetylene-based [0087] Cured with Desmodur 44V20 LF in the mixing ratio of 100:27 [0088] Index: 100

Physical Characteristics

[0089] Viscosity of polyol system (20° C.)=4300 mPas [0090] Hardness: Shore A=80 [0091] Specific surface resistivity 0.4 M Ω/cm [0092] Specific volume resistivity: 0.2 M Ω/cm

Comparative Example 1

[0093] 19.5 wt. % castor oil [0094] 51 wt. % castor oil-based polyester polyol with OHZ=185 mgKOH/g [0095] 1.0 wt. % dispersing additive [0096] 3.0 wt. % molecular sieve [0097] 0.5 wt. % nanotubes, predispersed [0098] 25 wt. % chalk [0099] Cured with Desmodur 44V20 LF in the mixing ratio: 100:31 [0100] Index: 102 [0101] Viscosity of polyol system (20° C.)=2230 mPas [0102] Specific surface resistivity: >50 G Ω/cm [0103] Specific volume resistivity: >50 G Ω/cm

Comparative Example 2

[0104] 39.5 wt. % castor oil [0105] 24.5 wt. % expoxidized soybean oil based polyester polyol OHZ=80 mgKOH/g [0106] 1.0 wt. % dispersing additive [0107] 3.0 wt. % molecular sieve [0108] 5 wt. % 1,4-butanediol [0109] 0.5 wt. % nanotubes, predispersed [0110] 25 wt. % chalk [0111] 1.5 wt. % carbon black, non-acetylene based [0112] Cured with Desmodur 44V20 LF in the mixing ratio: 100:36 [0113] Index: 102 [0114] Viscosity of the polyol system (20° C.) =2070 mPas [0115] Specific volume resistivity: 59 M Ω/cm

[0116] The following items are comprised by the present invention:

[0117] 1. A polyol composition comprising. [0118] (i) at least one polyol having a functionality of 2.2, [0119] (ii) carbon nanotubes, [0120] (iii) at least one carbon particle having a specific electrical resistance of ≤1Ω/cm measured according to IS 12178-1987 (Indian Standard), and [0121] (iv) optionally, at least one filler.

[0122] 2. The polyol composition of item 1, wherein component (i) comprises at least two polyols each having a functionality of 2.2.

[0123] 3. The polyol composition according to item 1 or 2, wherein component (i) comprises a polyester polyol having a functionality of 2.2.

[0124] 4. The polyol composition according to any one of the preceding items, wherein component (i) comprises a polyether polyol having a functionality of ≥2.2.

[0125] 5. The polyol composition according to any one of the preceding items, wherein component (i) comprises castor oil or a castor oil derivative having a functionality of ≥2.2.

[0126] 6. The polyol composition according to any one of the preceding items, wherein component (i) comprises at least one polyester polyol, castor oil, and optionally at least one polyether polyol, each having a functionality ≥2.2.

[0127] 7. The polyol composition according to any one of the preceding items, wherein the polyol with a functionality of ≥2.2 in component (i) has an OH number of 120-800 mg KOH/g, preferably 140-500 mg KOH/g, more preferably 140-450 mg KOH/g.

[0128] 8. The polyol composition according to any one of the preceding items, wherein component (i) has a total functionality of 2.2-5.0, preferably 2.2-4.0 and/or an OH number of 140-500 mg KOH/g, more preferably 140-450 mg KOH/g.

[0129] 9. The polyol composition according to any one of the preceding items, wherein component (i) has a total viscosity of 300-16,000 mPas, preferably 300-2,000 mPas, more preferably 300-1,200 mPas at 20° C. measured according to DIN EN 53019-1.

[0130] 10. The polyol composition according to any one of the preceding items, wherein component (i) accounts for 40-99.7 wt. %, based on the polyol composition.

[0131] 11. The polyol composition according to any one of the preceding items, wherein the carbon nanotubes are single-walled carbon nanotubes (SWCNTs).

[0132] 12. The polyol composition according to any one of the preceding items, wherein the carbon nanotubes have an average outer diameter of 0.5-50 nm, preferably 1.0-2.0 nm.

[0133] 13. The polyol composition according to any one of the preceding items, wherein the carbon nanotubes have an average length of 1-500 μm, preferably 1-50 μm, and wherein the carbon nanotubes preferably have an average aspect ratio of 20-1,000,000.

[0134] 14. The polyol composition according to any one of the preceding items, wherein the carbon nanotubes are dispersed in a carrier material.

[0135] 15. The polyol composition according to item 14, wherein the carrier material comprises a fatty acid ester, a fatty acid glycidyl ester, an alkyl glycidyl ester, a glycol ester, a fatty acid carboxylate ester derivative, an ethoxylated alcohol, distyryl biphenyl derivative, alkylene glycol, triethylene glycol dimethacrylate, polyolefin ammonium salt, or a mixture thereof.

[0136] 16. The polyol composition according to any one of the preceding items, wherein the carbon nanotubes have a specific electrical conductivity of 100-10,000 S/cm measured according to DIN ES 12178-1987 (Indian Standard).

[0137] 17. The polyol composition according to any one of the preceding items, wherein component (ii) accounts for 0.01-0.1 wt. %, preferably 0.02-0.05 wt. %, based on the polyol composition.

[0138] 18. The polyol composition according to any one of the preceding items, wherein the carbon particles are substantially amorphous.

[0139] 19. The polyol composition according to any one of the preceding items, wherein the carbon particles are obtainable by combustion of acetylene in the presence of sub-stoichiometric amounts of oxygen.

[0140] 20. The polyol composition according to any one of the preceding items, wherein the specific surface area of the carbon particles has a BET value of 5-300 m.sup.2/g, preferably 20-200 m.sup.2/g measured according to ASTM D 6556.

[0141] 21. The polyol composition according to any one of the preceding items, wherein component (iii) constitutes 0.2-4 wt. %, preferably 1.0-3.0 wt. %, based on the polyol composition.

[0142] 22. The polyol composition according to any one of the preceding items, wherein the weight ratio of components (ii):(iii) is 1:75-1:3.

[0143] 23. The polyol composition according to any one of the preceding items, wherein the filler is selected from the group consisting of inorganic or organic fillers, in particular carbonates, such as calcium carbonate or magnesium carbonate, dolomite, Al(OH).sub.3 or Al.sub.2O.sub.3, SiO.sub.2, barium sulfate, talc, zirconium oxide, or mixtures thereof.

[0144] 24. The polyol composition according to any one of the preceding items, wherein component (iv) accounts for 0-50 wt. %, preferably 0.01-35 wt. %, based on the polyol composition.

[0145] 25. The polyol composition according to any one of the preceding items, further comprising. [0146] (v) at least one excipient, such as defoamers, wetting and dispersing agents; and [0147] (vi) optionally, a water scavenger.

[0148] 26. The polyol composition according to any one of the preceding items, wherein component (v) constitutes 0-5 wt. %, preferably 0.001-2.5 wt. %, based on the polyol compositions.

[0149] 27. The polyol composition according to any one of the preceding items, wherein component (vi) constitutes 0.1-10 wt. %, preferably 1-5 wt. %, based on the polyol composition.

[0150] 28. A polyurethane system comprising [0151] (a) a polyol composition according to any one of items 1-27, and [0152] (b) at least one polyisocyanate.

[0153] 29. The polyurethane system according to item 28, wherein the polyisocyanate is selected from aromatic or aliphatic polyisocyanate, in particular MDI, oligomeric or polymeric MDI, TDI, HDI, IPDI, H.sub.12MDI or TMXDI.

[0154] 30. The polyurethane system according to item 28 or 29, wherein the polyisocyanate has an NCO content of ≥15%.

[0155] 31. The polyurethane system according to any one of items 28-30, wherein the molar ratio of isocyanate-reactive groups (e.g. —OH; —NH.sub.2 or —SH) to isocyanate groups is 1.0-1.1:1.1-1.0, preferably 1:1.

[0156] 32. A process for preparing a polyurethane comprising the steps of: [0157] (I) providing a polyol composition (a) according to any one of items 1-27, [0158] (II) providing at least one polyisocyanate (b), [0159] (III) mixing the polyol composition and the at least one polyisocyanate, optionally by adding a catalyst and optionally at elevated temperature.

[0160] 33. A polyurethane obtainable by a process according to item 32.

[0161] 34. The polyurethane according to item 32, wherein the surface resistivity is 0.05-0.5 M Ω/cm measured according to IEC 62631-3-2.

[0162] 35. The polyurethane according to any one of items 33 or 34, wherein the volume resistivity is 0.005-0.5 M Ω/cm measured according to ASTM D991/ISO 1853.

[0163] 36. The polyurethane according to any one of items 33-35, wherein the hardness is in the range of Shore A 40-Shore D 85.

[0164] 37. The use of a polyol composition according to any one of items 1-27, a polyurethane system according to any one of items 28-31 or a polyurethane according to any one of items 33-36 as an adhesive, sealant, in particular for filter casting.