Thermal conductive polymer molded article and method for producing the same

• US 7,079,405 B2
• Filed: 07/11/2003
• Issued: 07/18/2006
• Est. Priority Date: 07/11/2002
• Status: Expired due to Fees

• Current Assignee: Polymatech Company Limited
• Original Assignee: Polymatech Company Limited
• Inventors: Kimura, Toru, Tobita, Masayuki, Shimoyama, Naoyuki, Ishigaki, Tsukasa
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US10/617,517
• Publication Number:
  US 20040048054A1
• Time in Patent Office: 1,103 Days
• Field of Search: 363/21.1, 363/21.07, 363/41, 323/207
• US Class Current: 363/21.1
• CPC Class Codes: B29C 70/88 characterised primarily by possessing specific properties, e.g. electrically conductive or locally reinforced
• CPC Class Codes: B29C 71/00 After-treatment of articles without altering their shape; Apparatus therefor B29C44/56, B29C73/00 take precedence; surface shaping B29C59/00 ; for joined or sealed parts B29C66/03; after-treatment specially adapted for vulcanising tyres B29D30/0633
• CPC Class Codes: B29C 71/0081 using an electric field, e.g. for electrostatic charging electrostatic pinning of extruded material B29C48/9165; fixing linings by electrostatic charges B29C63/0043
• CPC Class Codes: B29K 2077/00 Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2077/10 Aromatic polyamides [polyaramides] or derivatives thereof
• CPC Class Codes: B29K 2105/0079 Liquid crystals
• CPC Class Codes: B29K 2995/0013 Conductive
• CPC Class Codes: C09K 19/3809 Polyesters; Polyester derivatives, e.g. polyamides

Abstract

A thermal conductive polymer molded article is formed by molding a thermotropic liquid crystalline composition comprised mainly of a thermotropic liquid crystalline polymer, wherein the thermal conductive polymer molded article is formed by applying a magnetic field or an electric field to the thermotropic liquid crystalline composition melted by heating so that the thermal conductive polymer molded article has a first thermal conductivity (λ₁) higher than a second thermal conductivity (λ₂) of a molded article formed by molding the thermotropic liquid crystalline polymer without the application of the field. The thermal conductive polymer molded article preferably has a first thermal conductivity (λ₁) of between 0.7 and 20 W/(m·K). Preferably, the thermotropic liquid crystalline polymer comprises at least one polymer selected from (A) a wholly aromatic polyester and (B) a wholly aromatic polyester amide.

Claims

1. A thermal conductive polymer molded article formed by molding a thermotropic liquid crystalline composition comprised mainly of a thermotropic liquid crystalline polymer, wherein the thermal conductive polymer molded article is formed by applying a field selected from the group consisting of a magnetic field and an electric field to the thermotropic liquid crystalline composition melted by heating so that the thermal conductive polymer molded article has a first thermal conductivity (λ

₁) higher than a second thermal conductivity (λ

₂) of a molded article formed by molding the thermotropic liquid crystalline polymer without said application of a magnetic field or an electric field.

2. The thermal conductive polymer molded article according to claim 1, wherein the thermotropic liquid crystalline composition consists solely of the thermotropic liquid crystalline polymer.

3. The thermal conductive polymer molded article according to claim 1, wherein the thermotropic liquid crystalline composition comprises 100 parts by weight of the thermotropic liquid crystalline polymer and 5 parts by weight or less of a thermal conductive filler relative to the thermotropic liquid crystalline polymer.

4. The thermal conductive polymer molded article according to claim 1, wherein the thermal conductive polymer molded article has the first thermal conductivity (λ

₁) of between 0.7 and 20 W/(m·

K).

5. The thermal conductive polymer molded article according to claim 1, wherein the thermotropic liquid crystalline polymer comprises at least one polymer selected from the group consisting of (A) a wholly aromatic polyester and (B) a wholly aromatic polyester amide.

6. The thermal conductive polymer molded article according to claim 1, wherein the molded article has a density of 1.10 to less than 1.50 g/cm³.

7. The thermal conductive polymer molded article according to claim 1, wherein the thermal conductive polymer molded article is in a sheet form and has a thermal conductivity (λ

_1T) of between 0.7 and 20 W/(m·

K) in the thickness direction of the sheet.

8. The thermal conductive polymer molded article according to claim 1, wherein the difference (λ

₁−

λ

₂) between the first thermal conductivity (λ

₁) and the second thermal conductivity (λ

₂) is between 0.2 and 19.8 W/(m·

K).

9. The thermal conductive polymer molded article according to claim 1, wherein said thermal conductive polymer molded article is in a sheet form and has a thermal conductivity (λ

_1P) of between 0.7 and 20 W/(m·

K) in the direction parallel to the surface of the sheet.

10. A method for producing a thermal conductive polymer molded article, the method comprising steps of:

melting by heating a polymer selected from the group consisting of a thermotropic liquid crystalline polymer and a thermotropic liquid crystalline composition;

applying a field, selected from the group consisting of a magnetic field and an electric field, to the melted polymer; and

solidifying by cooling the melted polymer after the step of applying the field to the melted polymer.

11. The method for producing a thermal conductive polymer molded article according to claim 10, wherein the melting step comprises a step of molding the polymer into a sheet form, and the step of applying the field to the polymer comprises a step of applying the field in the thickness direction of the sheet form.

12. The method for producing a thermal conductive polymer molded article according to claim 10, wherein the melting step comprises a step of molding the polymer into a sheet form, and the step of applying the field to the polymer comprises a step of applying the field in the direction parallel to the surface of the sheet form.

13. A method for controlling a thermal conductive polymer molded article in thermal conductivity, the method comprising steps of:

melting by heating a polymer selected from the group consisting of a thermaotropic liquid crystalline composition; and

applying a field selected from the group consisting of a magnetic field and an electric field to the melted polymer, wherein the direction of the field is controlled to the direction in which the first thermal conductivity (λ

₁) of the thermal conductive polymer molded article is improved.