Liquid crystalline polyester and molded article thereof

• US 8,337,719 B2
• Filed: 12/02/2008
• Issued: 12/25/2012
• Est. Priority Date: 12/03/2007
• Status: Expired due to Fees

• Current Assignee: Sumitomo Chemical Company Limited
• Original Assignee: Sumitomo Chemical Company Limited
• Inventors: Hosoda, Tomoya, Uehara, Tomoko, Okamoto, Satoshi
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US12/745,264
• Publication Number:
  US 20100271268A1
• Time in Patent Office: 1,484 Days
• Field of Search: 343/700.R, 252/299.62, 252/299.66, 252/299.67, 252/299.5, 528/176, 528/190, 528/193, 528/194
• US Class Current: 252/299.62
• CPC Class Codes: B29B 7/007 for continuous mixing
• CPC Class Codes: B29B 7/38 rotary B29B7/52 takes precedence
• CPC Class Codes: B29B 7/90 Fillers or reinforcements , e.g. fibres
• CPC Class Codes: B29B 9/06 in the form of filamentary material, e.g. combined with extrusion
• CPC Class Codes: B29B 9/12 characterised by structure or composition
• CPC Class Codes: B29B 9/14 fibre-reinforced
• CPC Class Codes: C08J 2367/00 Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
• CPC Class Codes: C08J 3/12 Powdering or granulating
• CPC Class Codes: C08J 3/2056 the polymer being pre-melted

Abstract

The present invention provides a resin composition containing a liquid crystalline polyester and a high dielectric material filler. The present invention also provides a molded article of the liquid crystalline polyester resin composition. The liquid crystalline polyester resin composition of the present invention comprises 50 to 80% by volume of a liquid crystalline polyester which has 40% by mol or more of a 2,6-naphthalenediyl group as an aromatic group, also has a flow initiation temperature of 280° C. or higher, and shows a melt tension of 1 g or more measured at a temperature higher than flow initiation temperature; and 20 to 50% by volume of a high dielectric material filler. The liquid crystalline polyester resin composition can be formed into composition pellets easily and stably by a strand method, and a molded article obtained from the liquid crystalline polyester resin composition is excellent in flexural strength and dielectric characteristics.

Claims

1. A liquid crystalline polyester resin composition comprising:

50 to 80% by volume of a liquid crystalline polyester (A) having a structural unit represented by the formula (I) shown below, a structural unit represented by the formula (II) shown below and a structural unit represented by the formula (iii) shown below, wherein the polyester (A) contains 40% by mol or more of a 2,6-naphthalenediyl group on the basis of 100% by mol of the total of a divalent aromatic group represented by Ar₁, a divalent aromatic group represented by Ar₂ and a divalent aromatic group represented by Ar₃, also has a flow initiation temperature of 280°

C. or higher and shows a melt tension of 1 g or more measured at a temperature higher than the flow initiation temperature; and

20 to 50% by volume of a filler (B) comprising a high dielectric material;

2. The liquid crystalline polyester resin composition according to claim 1, wherein the filler (B) comprising a high dielectric material is a filler containing titanium-based ceramics.

3. The liquid crystalline polyester resin composition according to claim 2, wherein the titanium-based ceramics mainly contain ceramics selected from among TiO₂, BaTiO₃, SrTiO₃, CaTiO₃, MgTiO₃, BaSrTi₂O₆, BaNd₂Ti₄O₁₂, BaNd₂Ti₅O₁₄ and BaBi₂Nd₂TiO₉.

4. A molded article comprising the liquid crystalline polyester resin composition according to claim 1.

5. The molded article according to claim 4, wherein the molded article has a flexural strength, measured by a test method defined in ASTM D790, of 100 MPa or more.

6. The molded article according to claim 4, wherein the molded article has an impact strength, measured by a test method defined in ASTM D256, of 100 J/m or more.

7. The molded article according to claim 4, wherein the molded article has a relative permittivity of 6.0 or more at a measuring temperature of 23°

C. and a frequency of 1 GHz.

8. An antenna comprising the molded article according to claim 4, and an electrode.

9. A method for producing the liquid crystalline polyester resin composition according to claim 1, the method comprising steps of:

(i) heat-melting the liquid crystalline polyester (A) and the filler (B) comprising a high dielectric material to obtain a molten composition;

(ii) extruding the molten composition into a strand shape to obtain a strand-shaped composition; and

(iii) cutting the strand-shaped composition into pellets to obtain the liquid crystalline polyester resin composition.