Process for forming improved liquid crystalline polymer blends

• US 5,393,848 A
• Filed: 02/12/1993
• Issued: 02/28/1995
• Est. Priority Date: 01/16/1990
• Status: Expired due to Term

• Current Assignee: CNA Holdings Incorporated (Celanese Corporation)
• Original Assignee: Hoechst Celanese Corporation (Sanofi )
• Inventors: Gupta, Balaram, Linstid, H. Clay, Charbonneau, Larry F., Shepherd, James P., Sawyer, Linda C.
• Primary Examiner(s): Short, Patricia A.
• Application Number:
  US08/017,948
• Time in Patent Office: 746 Days
• Field of Search: 525/420, 525/425, 525/437, 525/439, 525/444, 525/450, 524/537, 524/538, 524/539
• US Class Current: 525/425
• CPC Class Codes: C08G 63/605 the hydroxy and carboxylic groups being bound to aromatic rings
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 2666/18 Polyesters or polycarbonates according to C08L67/00 - C08L69/00; Derivatives thereof
• CPC Class Codes: C08L 67/00 Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain of polyester-amides C08L77/12; of polyester-imides C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 77/12 Polyester-amides
• CPC Class Codes: C09K 19/3809 Polyesters; Polyester derivatives, e.g. polyamides

Abstract

An improved liquid crystalline polymer blend is produced by mixing a preformed thermotropic liquid crystalline polymer in the melt phase with reactants needed to form a second liquid crystalline polymer under conditions sufficient to form the second liquid crystalline polymer. The resulting blends are anisotropic and have improved morphology and improved melt processability. The method is particularly useful when the second liquid crystalline polymer is biphasic or is difficult to synthesize or process in the melt.

Claims

1. A method for producing a liquid crystalline polymer blend comprising the steps of:

(a) mixing a preformed thermotropic liquid crystalline polymer with the reactants necessary to form a second liquid crystalline polymer, wherein said second liquid crystalline polymer is an aromatic polyester, said reactants necessary to form said second liquid crystalline polymer comprising aromatic molecules, each having substituents capable of reacting to from aromatic ester linkages; and

(b) heating the mixture of said reactants and said preformed thermotropic liquid crystalline polymer above the melting temperature of said preformed liquid crystalline polymer at a temperature and for a time period sufficient for said reactants to combine to form said second liquid crystalline polymer in a uniform blend with said preformed thermotropic liquid crystalline polymer.

2. A method for producing a liquid crystalline polymer blend as recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer comprises a blend of at least two liquid crystalline polymers, one component of said blend optionally being said second liquid crystalline polymer.

3. The method as recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer is provided in a concentration of about 0.5% to about 70% by weight of the liquid crystalline polymer blend.

4. The method as recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer is provided in a concentration of about 2% to about 50% by weight of the liquid crystalline polymer blend.

5. The method of claim 1, wherein said preformed thermotropic liquid crystalline polymer is selected from the group consisting of aromatic polyesters, aliphatic-aromatic polyesters, poly(ester-amides), poly(ester-carbonates) and mixtures thereof.

6. The method as recited in claim 5, wherein said preformed thermotropic aromatic polyester comprises at least about 10% of recurring units which include a naphthalene moiety.

7. The method as recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer is an aromatic polyester comprising at least one repeat unit derived from a monomer selected from the group consisting of 6-hydroxy-2-naphthoic acid, 2,6-dihydroxynaphthalene, 2,6-naphthalenedicarboxylic acid, 4-hydroxybenzoic acid, 1,4-hydroquinone, terephthalic acid and isophthalic acid.

8. The method as recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer comprises 6-oxy-2-naphthoyl and 4-oxybenzoyl molecular repeat units.

9. The method as recited in claim 8, wherein said second liquid crystalline polymer is a polyester comprising 4,4'"'"'-dioxybiphenylene, 4-oxybenzoyl and terephthaloyl molecular repeat units.

10. The method as recited in claim 8, wherein said second liquid crystalline polymer is poly[co(4-oxybenzoate/1,4-phenyleneisophthalate)].

11. The method was recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer comprises 6-oxy-2-naphthoyl, terephthaloyl and p-aminophenoxy repeat units.

12. The method as recited in claim 1 wherein said preformed thermotropic liquid crystalline polymer comprises 6-oxy-2-naphthoyl repeat units, terephthaloyl repeat units, optional 4-oxybenzoyl repeat units, and at least one repeat unit selected from the group consisting of 1,4-dioxyphenylene, 4,4'"'"'-dioxybiphenylene and substituted derivatives thereof.

13. The method as recited in claim 1 wherein said preformed thermotropic liquid crystalline polymer comprises 4-oxybenzoyl, terephthaloyl and 1,4-dioxy-2-phenylphenylene molecular repeat units.

14. The method as recited in claim 1, wherein said second liquid crystalline polymer forms a biphasic melt, one phase of said biphasic melt being anisotropic.

15. The method as recited in claim 1, wherein said second liquid crystalline polymer comprises 4-oxybenzoyl, isophthaloyl, 1,4-dioxyphenylene, optional terephthaloyl, and optional 4,4'"'"'-dioxybiphenylene molecular repeat units.

16. The method as recited in claim 1, wherein said second liquid crystalline polymer is poly[co(4-oxybenzoate/1,4-phenyleneisophthalate)].

17. The method as recited in claim 1, wherein said second liquid crystalline polymer is formed by melt acidolysis polymerization.

18. The method as recited in claim 17, wherein said reactants necessary to form said second liquid crystalline polymer comprise sufficient acetic anhydride to esterify the phenolic groups to acetate groups before said aromatic ester linkages are formed.

19. The method as recited in claim 1, wherein said preformed thermotropic liquid crystalline polymer is provided in a concentration of about 3% to about 10% by weight of the liquid crystalline polymer blend.

20. The method as recited in claim 1, wherein said temperature is in the range of about 200°

C. to about 400°

C.

21. The method as recited in claim 1, wherein said temperature does not exceed about 350°

C.

22. In a process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] in a stirred heated reaction zone via melt-acidolysis polymerization reaction of appropriate monomers, the improvement of providing in said reaction zone during a substantial portion of said polymerization in a well-dispersed form approximately 0.5 to 15 percent by weight of molten preformed polymer selected from the group consisting of anisotropic melt-forming poly(ester-amides), anisotropic melt-forming poly(ester-carbonates), anisotropic melt-forming wholly aromatic polyesters containing recurring units which include a naphthalene moiety, and mixtures thereof which is capable of forming an anisotropic single phase melt with the concentration of said preformed polymer being based upon the total concentration of monomers initially present in said reaction zone.