Carbon-reinforced PC-ABS composition and articles made from same

• US 6,596,199 B2
• Filed: 02/27/2001
• Issued: 07/22/2003
• Est. Priority Date: 02/03/2000
• Status: Expired due to Term

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: General Electric Company
• Inventors: Patel, Nirajkumar
• Primary Examiner(s): Kopec, Mark
• Application Number:
  US09/794,175
• Publication Number:
  US 20010023937A1
• Time in Patent Office: 875 Days
• Field of Search: 252/511, 524/495, 106/472, 264/5, 264/614, 264/641
• US Class Current: 252/511
• CPC Class Codes: B29C 45/0001 characterised by the choice of material
• CPC Class Codes: B29C 45/0005 using fibre reinforcements
• CPC Class Codes: C08K 7/06 Elements
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 55/02 ABS [Acrylonitrile-Butadiene-Styrene] polymers
• CPC Class Codes: C08L 69/00 Compositions of polycarbonates; Compositions of derivatives of polycarbonates
• CPC Class Codes: C08L 77/00 Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon

Abstract

Carbon fiber-filled PC-ABS resin compositions which have improved electrical properties at a given level of carbon fibers, and which do not suffer from as significant a decrease in impact strength as would result from the introduction of generic carbon fibers are achieved using carbon fibers treated with a polyamide terpolymer binder. The bundles are dispersed within the PC-ABS blend. The compositions can be used for injection molding of articles for use as components in applications requiring static dissipation and/or EMI shielding. Such articles include, but are not limited to electronic devices, dust handling equipment and notebook computer enclosures.

Claims

1. A composition comprising:

(a) a thermoplastic resin comprising a blend of polycarbonate and acrylonitrile-butadiene-styrene copolymer; and

(b) carbon fibers associated into bundles with a polyamide terpolymer binder, said bundles being dispersed within the thermoplastic resin wherein said composition has a surface resistivity below 10⁵ Ohm/Sq.

2. The composition of claim 1, wherein the carbon fibers are present in an amount of from 5 to 50% by weight of the composition.

3. The composition of claim 2, wherein the binder is present in an amount of from 0.5 to 10% by weight of the carbon fibers.

4. The composition of claim 1, wherein the binder is present in an amount of from 0.5 to 10% by weight of the carbon fibers.

5. The composition of claim 1, further comprising a flame retardant.

6. The composition of claim 1, wherein the blend comprises polycarbonate and acrylonitrile-butadiene-styrene copolymer in a ratio of from 10:

90 to 90;

10, by weight.

7. The composition of claim 6, wherein the carbon fibers are present in an amount of from 5 to 50% by weight of the composition.

8. The composition of claim 7, wherein the binder is present in an amount of from 0.5 to 10% by weight of the carbon fibers.

9. A method for making an injection-molded article comprising the steps of:

(a) preparing a composition comprising a thermoplastic resin comprising a blend of polycarbonate and acrylonitrile-butadiene-styrene copolymer, and carbon fibers associated into bundles with a polyamide terpolymer binder, said bundles being dispersed within the thermoplastic resin;

(b) heating the composition to melt the thermoplastic resin; and

(c) injecting the heated composition into a mold shaped to form the article wherein said injection-molded article has a surface resistivity below 10⁵ Ohm/Sq.

10. The method of claim 9, wherein the carbon fibers are present in an amount of from 5 to 50% by weight of the composition.

11. The method of claim 10, wherein the binder is present in an amount of from 0.5 to 10% by weight of the carbon fibers.

12. The method of claim 9, wherein the blend comprises polycarbonate and acrylonitrile-butadiene-styrene copolymer in a ratio of from 10:

90 to 90;

10 by weight.

13. An injection-molded article prepared by a method comprising the steps of:

(a) preparing a composition comprising a thermoplastic resin comprising a blend of polycarbonate and acrylonitrile-butadiene-styrene copolymer, and carbon fibers associated into bundles with a polyamide terpolymer binder, said bundles being dispersed within the thermoplastic resin;

(b) heating the composition to melt the thermoplastic resin; and

(c) injecting the heated composition into a mold shaped to form the article wherein said injection-molded article has a surface resistivity below 10⁵ Ohm/Sq.

14. The article of claim 13, wherein the carbon fibers are present in an amount of from 5 to 50% by weight of the composition.

15. The article of claim 14, wherein the binder is present in an amount of from 0.5 to 10% by weight of the carbon fibers.

16. The article of claim 13, wherein the blend comprises polycarbonate and acrylonitrile-butadiene-styrene copolymer in a ratio of from 10:

90 to 90;

10 by weight.

17. A method for increasing the impact strength of a PC-ABS blend having carbon fibers dispersed therein, comprising the step of coating the carbon fibers with a polyamide terpolymer binder prior to dispersing them in the PC-ABS blend, wherein the PC-ABS blend having carbon fibers has a surface resistivity below 10⁵ Ohm/Sq.