Extrudable thermoplastic elastomeric urea-extended polyurethane

• US 5,811,506 A
• Filed: 02/03/1997
• Issued: 09/22/1998
• Est. Priority Date: 02/03/1997
• Status: Expired due to Term

• Current Assignee: BAE Systems Simula, Inc. (Safariland LLC)
• Original Assignee: BAE Systems Simula, Inc. (Safariland LLC)
• Inventors: Slagel, Edwin C.
• Primary Examiner(s): SERGENT, RABON A
• Application Number:
  US08/794,746
• Time in Patent Office: 596 Days
• Field of Search: 524/230, 524/233, 524/448, 524/726, 524/728, 524/789, 524/791, 528/61, 528/64, 528/67, 528/76, 528/80, 528/83, 264/176.1, 264/209.1, 264/211.12, 264/563
• US Class Current: 528/64
• CPC Class Codes: C08G 18/0895 Manufacture of polymers by continuous processes C08G18/0838 takes precedence
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/12 using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/3237 aromatic C08G18/3234 takes precedence
• CPC Class Codes: C08G 18/4266 prepared from hydroxycarboxylic acids and/or lactones
• CPC Class Codes: C08G 18/4277 Caprolactone and/or substituted caprolactone
• CPC Class Codes: C08G 18/758 containing two or more cycloaliphatic rings

Abstract

An extrudable urea-extended thermoplastic polyurethane elastomer is formed from at least one aliphatic diisocyanate, at least one polyester glycol or polyether glycol, and at least one diamine curing agent. At least one second diamine curing agent and/or at least one extrusion processing aid may be included. The polyurethane has high-temperature-resistance and is thus extrudable at high temperatures. The polyurethane is also strong and durable. The polyurethane can be liquid-cast, injection-molded, transfer-molded, sprayed, and extruded without changing either the chemistry or stoichiometry of the polyurethane. The polyurethane may be used for making vehicle air bags or other any application for thermoplastic urethanes which requires increased thermal stability.

Claims

1. An extrudable thermoplastic elastomeric urea-extended polyurethane comprising the reaction product of:

(a) a polyurethane prepolymer comprising the reaction product of at least one aliphatic diisocyanate with at least one hydroxy-containing intermediate selected from the group consisting of polyester glycols, polyether glycols, and mixtures thereof,

(b) at least one first diamine curing agent selected from the group consisting of 2,4-diamino-3,5-diethyl-toluene, 2,6-diamino-3,5-diethyl-toluene, and methylene dianiline, and

(c) at least one second diamine curing agent selected from the group consisting of 4,4'"'"'-methylene-bis(2,6-diisopropylaniline), 4,4'"'"'-methylene-bis(2,6-dimethylaniline), 4,4'"'"'-methylene-bis(2-ethyl-6-methylaniline), 4,4'"'"'-methylene-bis(2,6-diethylaniline), 4,4'"'"'-methylene-bis(2-isopropyl-6-methylaniline), 4,4'"'"'-methylene-bis(2,6-diethyl-3-chloroaniline), and trimethylene glycol di-para aminobenzoate.

2. The polyurethane according to claim 1, wherein the at least one first diamine curing agent comprises 20 to 98 percent by equivalents of a total amount of diamine curing agents, and the at least one second diamine curing agent comprises 2 to 80 percent by equivalents of the total amount of diamine curing agents.

3. The polyurethane according to claim 1, wherein the at least one first diamine curing agent comprises 40 to 98 percent by equivalents of a total amount of diamine curing agents, and the at least one second diamine curing agent comprises 2 to 60 percent by equivalents of the total amount of diamine curing agents.

4. The polyurethane according to claim 1, wherein the at least one aliphatic diisocyanate is selected from the group consisting of 4,4'"'"'-dicyclohexylmethane diisocyanate, 3-isocyanato-methyl-3,5,5-trimethylcyclohexyl isocyanate, and tetramethylxylene diisocyanate.

5. The polyurethane according to claim 1, wherein the at least one aliphatic diisocyanate is 4,4'"'"'-dicyclohexylmethane diisocyanate.

6. The polyurethane according to claim 5, wherein the 4,4'"'"'-dicyclohexylmethane diisocyanate contains at least 20 weight percent of a trans, trans isomer of 4,4'"'"'-dicyclohexylmethane diisocyanate.

7. The polyurethane according to claim 5, wherein the 4,4'"'"'-dicyclohexylmethane diisocyanate contains at least 50 weight percent of the trans, trans isomer of 4,4'"'"'-dicyclohexylmethane diisocyanate.

8. The polyurethane according to claim 5, wherein the 4,4'"'"'-dicyclohexylmethane diisocyanate contains at least 80 weight percent of the trans, trans isomer of 4,4'"'"'-dicyclohexylmethane diisocyanate.

9. The polyurethane according to claim 1, wherein the at least one hydroxy-containing intermediate has a weight average molecular weight of about 500 to about 3000.

10. The polyurethane according to claim 9, wherein the at least one hydroxy-containing intermediate is a polyester glycol comprising at least one polycaprolactone which has been prepared by the addition reaction of caprolactone in the presence of at least one aliphatic glycol having 2 to 12 carbon atoms.

11. The polyurethane according to claim 10, wherein said at least one aliphatic glycol is selected from the group consisting of ethylene glycol, diethylene glycol, 1,4-butane diol, neopentyl glycol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, and mixtures thereof.

12. The polyurethane according to claim 9, wherein the at least one hydroxy-containing intermediate is a polyester glycol comprising at least one polyester which has been prepared by condensing at least one aliphatic dicarboxylic acid having 2 to 12 carbon atoms in the presence of at least one aliphatic glycol having 2 to 12 carbon atoms.

13. The polyurethane according to claim 12, wherein the at least one aliphatic dicarboxylic acid is selected from the group consisting of adipic acid, succinic acid, sebacic acid, and mixtures thereof.

14. The polyurethane according to claim 12, wherein the at least one aliphatic glycol is selected from the group consisting of ethylene glycol, diethylene glycol, 1,4-butane diol, neopentyl glycol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, and mixtures thereof.

15. The polyurethane according to claim 9, wherein the at least one hydroxy-containing intermediate is a polyether glycol comprising polytetramethylene ether glycol.

16. The polyurethane according to claim 2, wherein the first diamine curing agent is selected from the group consisting of 2,4-diamino-3,5-diethyl-toluene, 2,6-diamino-3,5-diethyl-toluene, and mixtures thereof, and the second diamine curing agent is 4,4'"'"'-methylene-bis(2,6-diethylaniline).

17. The polyurethane according to claim 1, wherein the extrudable thermoplastic urethane has a shore A hardness of about 80 and a melt flow index ranging from about 5 to 40 inches per minute when measured in accordance with ASTM D-1238, modified to reduce dwell time.

18. A process for making an extrudable thermoplastic elastomeric urea-extended polyurethane comprising the steps of:

(a) reacting at least one aliphatic diisocyanate with at least one hydroxy-containing intermediate selected from the group consisting of polyester glycols and polyether glycols, to form a prepolymer, and

(b) reacting said prepolymer with at least one first diamine curing agent selected from the group consisting of 2,4-diamino-3,5-diethyl-toluene, 2,6-diamino-3,5-diethyl-toluene, and methylene dianiline, and with at least one second diamine curing agent selected from the group consisting of 4,4'"'"'-methylene-bis(2,6-diisopropylaniline), 4,4'"'"'-methylene-bis(2,6-dimethylaniline), 4,4'"'"'-methylene-bis(2-ethyl-6-methylaniline), 4,4'"'"'-methylene-bis(2,6-diethylaniline), 4,4'"'"'-methylene-bis(2-isopropyl-6-methylaniline), 4,4'"'"'-methylene-bis(2,6-diethyl-3-chloroaniline), and trimethylene glycol di-para aminobenzoate.

19. The process according to claim 18, wherein the process is conducted in an environment containing no more than 0.03 weight percent of water based on the weight of total ingredients.

20. The process according to claim 18, wherein the at least one aliphatic diisocyanate is mixed with the at least one hydroxy-containing intermediate in an equivalent ratio of two NCO groups to one OH group.

21. The process according to claim 18, wherein the process further comprises pelletizing the polyurethane formed.

22. The process according to claim 18, wherein the process further comprises extruding the polyurethane formed.

23. A process for forming a product comprising

(a) heating a thermoplastic elastomeric urea-extended polyurethane comprising the reaction product of at least one aliphatic diisocyanate, at least one hydroxy-containing intermediate selected from the group consisting of polyester glycols, polyether glycols, and mixtures thereof, and at least one diamine curing agent comprising at least one member selected from the group consisting of 2,4-diamino-3,5-diethyl-toluene, 2,6-diamino-3,5-diethyl-toluene, and methylene dianiline, and at least one member selected from the group consisting of 4,4'"'"'-methylene-bis(2,6-diisopropylaniline), 4,4'"'"'-methylene-bis(2,6-dimethylaniline), 4,4'"'"'-methylene-bis(2-ethyl-6-methylene), 4,4'"'"'-methylene-bis(2,6-diethylaniline), 4,4'"'"'-methylene-bis(2-isopropyl-6-methylaniline), 4,4'"'"'-methylene-bis(2,6-diethyl-3-chloroaniline), and trimethylene glycol di-para aminobenzoate, and

(b) extruding the heated polyurethane to form an extruded product.

24. The process according to claim 23, wherein the extruding is conducted at a temperature of about 215°

C. to about 310°

C.

25. The process according to claim 23, wherein the extruding is conducted at a pressure of about 3299 to about 5362 psi.

26. The process according to claim 23, wherein the process further comprises post curing the extruded product.

27. An extruded polyurethane product formed by the process of claim 23.

28. An extruded polyurethane product according to claim 27, wherein said product is an inflatable tubular structure.