Heat-Resistant Liquid Crystalline Polymer Composition having a Low Melting Temperature

• US 20130048908A1
• Filed: 08/27/2012
• Published: 02/28/2013
• Est. Priority Date: 08/29/2011
• Status: Active Grant

• Current Assignee: Ticona LLC (Celanese Corporation)
• Original Assignee: Ticona LLC (Celanese Corporation)
• Inventors: Gray, Steven D., Nair, Kamlesh P., Grenci, Joseph J.
• Granted Patent: US 8,906,258 B2
• Time in Patent Office: Days
• US Class Current: 252/299.5
• CPC Class Codes: C09K 19/22 linked by a chain containing carbon and nitrogen atoms as chain links, e.g. Schiff bases
• CPC Class Codes: C09K 19/3086 in which at least two rings are linked by a chain containing nitrogen atoms
• CPC Class Codes: C09K 19/322 Compounds containing a naphthalene ring or a completely or partially hydrogenated naphthalene ring
• CPC Class Codes: C09K 19/3444 the heterocyclic ring being a six-membered aromatic ring containing one nitrogen atom, e.g. pyridine
• CPC Class Codes: C09K 19/48 containing Schiff bases
• CPC Class Codes: C09K 2019/0481 Phenylene substituted in meta position

Abstract

A thermotropic liquid crystalline polymer composition capable of exhibiting both a low melting temperature and good heat resistance without the use of conventional naphthenic acids is provided. The melting temperature may, for example, range from about 250° C. to about 400° C. Even at such low melting temperatures, the present inventors have surprisingly discovered that the ratio of the deflection temperature under load (“DTUL”), a measure of short term heat resistance, to the melting temperature may remain relatively high. The specific DTUL values may range from about 200° C. to about 300° C. The ability to form a polymer composition with the properties noted above may be achieved, at least in part, by the use of an aromatic amide oligomer.

Claims

1. A thermotropic liquid crystalline polymer composition that comprises a melt-polymerized liquid crystalline polymer, wherein the total amount of repeating units in the polymer derived from naphthenic hydroxcarboxylic or naphthenic dicarboxylic acids is no more than about 5 mol. %, and wherein the polymer composition has a melting temperature of from about 250°

C. to about 400°

C. and exhibits a deflection temperature under load such that the ratio of the deflection temperature under load to the melting temperature is from about 0.5 to about 1, the deflection temperature under load being determined in accordance ISO Test No. 75-2 at a load of 1.8 Megapascals.

2. The polymer composition of claim 1, wherein the liquid crystal polymer is wholly aromatic.

3. The polymer composition of claim 1, wherein the melting temperature is from about 300°

C. to about 360°

C.

4. The polymer composition of claim 1, wherein the ratio of the deflection temperature under load to the melting temperature is from about 0.7 to about 0.8.

5. The polymer composition of claim 1, wherein the deflection temperature under load is from about 210°

C. to about 280°

C.

6. The polymer composition of claim 1, wherein the polymer is a wholly aromatic polyester containing repeating units derived from 4-hydroxybenzoic acid and terephthalic acid.

7. The polymer composition of claim 6, wherein the repeating units derived from 4-hydroxybenzoic acid constitutes from about 50 mol. % to about 95 mol. % of the polymer and the repeating units derived from terephthalic acid constitute from about 1 mol. % to about 25 mol. % of the polymer.

8. The polymer composition of claim 7, wherein the polymer contains repeating units derived from isophthalic acid, hydroquinone, 4,4-biphenol, or a combination thereof.

9. The polymer composition of claim 1, wherein the total amount of repeating units in the polymer derived from naphthenic hydroxcarboxylic or naphthenic dicarboxylic acids is no more than about 2 mol. %.

10. The polymer composition of claim 1, further comprising an aromatic amide oligomer having the following general formula (I):

11. The polymer composition of claim 9, wherein ring B is phenyl.

12. The polymer composition of claim 9, wherein m is 0.

13. The polymer composition of claim 9, wherein B is naphthyl.

14. The polymer composition of claim 1, wherein the aromatic amide oligomer has the following general formula (IV):

15. The polymer composition of claim 14, wherein m is 0.

16. The polymer composition of claim 1, wherein the aromatic amide oligomer has the following general formula (V):

17. The polymer composition of claim 16, wherein m is 0.

18. The polymer composition of claim 1, wherein the aromatic amide oligomer has the following general formula (VI):

19. The polymer composition of claim 1, wherein the oligomer is selected from the group consisting of the following compounds and combinations thereof:

20. The polymer composition of claim 1, wherein the oligomer is N1,N4-diphenylterephthalamide, N1,N4-diphenylisoterephthalamide, 1,3-benzenedicarboxamide, N1,N3-dicyclohexyl, 1,4-benzenedicarboxamide, N1,N3-dicyclohexyl, or N1,N3,N5-triphenylbenzene-1,3,5-tricarboxamide.

21. The polymer composition of claim 1, wherein the oligomer contains from 2 to 8 amide functional groups per molecule.

22. The polymer composition of claim 1, wherein aromatic amide oligomers are employed in an amount of from about 0.1 to about 5 parts by weight relative to 100 parts by weight of the liquid crystalline polymer.

23. A filled polymer composition comprising the polymer composition of claim 1 and a filler material.

24. The filled polymer composition of claim 23, wherein the filler material comprises fibers, a mineral filler, or a combination thereof.

25. A thermotropic liquid crystalline polymer composition that comprises a liquid crystalline polymer and an aromatic amide oligomer in an amount of from about 0.1 to about 5 parts by weight relative to 100 parts by weight of the polymer, wherein the polymer composition has a melting temperature of from about 250°

C. to about 400°

C. and exhibits a deflection temperature under load such that the ratio of the deflection temperature under load to the melting temperature is from about 0.5 to about 1, the deflection temperature under load being determined in accordance with ISO Test No. 75-2 at a load of 1.8 Megapascals.

26. The polymer composition of claim 25, wherein the liquid crystalline polymer is a wholly aromatic liquid crystalline polymer.

27. The polymer composition of claim 25, wherein the melting temperature is from about 300°

C. to about 360°

C.

28. The polymer composition of claim 25, wherein the ratio of the deflection temperature under load to the melting temperature is from about 0.7 to about 0.8.

29. The polymer composition of claim 25, wherein the deflection temperature under load is from about 210°

C. to about 280°

C.

30. The polymer composition of claim 25, wherein the polymer contains no more than about 5 mol. % of repeating units derived from naphthenic hydroxcarboxylic acids and naphthenic dicarboxylic acids.

31. The polymer composition of claim 25, wherein the aromatic amide oligomer has the following general formula (I):

32. The polymer composition of claim 31, wherein ring B is phenyl.

33. The polymer composition of claim 31, wherein ring B is naphthyl.

34. The polymer composition of claim 25, wherein the oligomer is selected from the group consisting of the following compounds and combinations thereof:

35. The polymer composition of claim 25, wherein aromatic amide oligomers are employed in an amount of from about 0.5 to about 3 parts by weight relative to 100 parts by weight of the liquid crystalline polymer.

36. A filled polymer composition comprising the polymer composition of claim 25 and a filler material.

37. The filled polymer composition of claim 36, wherein the filler material is a fibrous filler, a mineral filler, or a combination thereof.

38. The filled polymer composition of claim 36, wherein the filled polymer composition has a tensile strength of greater than about 150 MPa.

39. The polymer composition of claim 36, wherein the filled polymer composition has a flexural strength of greater than about 225 MPa.