Form-in-place EMI gaskets

• US 6,331,349 B1
• Filed: 01/05/2000
• Issued: 12/18/2001
• Est. Priority Date: 09/10/1993
• Status: Expired due to Term

• Current Assignee: Parker Intangibles LLC (Parker-Hannifin Corporation)
• Original Assignee: Parker-Hannifin Corporation
• Inventors: Bunyan, Michael H., Kalinoski, John P.
• Primary Examiner(s): Nakarani, D. S.
• Application Number:
  US09/478,017
• Time in Patent Office: 713 Days
• Field of Search: 174/35 R, 174/35 GC, 174/35 MS, 428/328, 428/220, 428/425.8, 428/425.9, 428/450, 428/462, 428/463, 428/35.8, 428/458, 428/480, 252/510, 252/511, 252/514, 252/521.3
• US Class Current: 428/220
• CPC Class Codes: F16J 15/064 the packing combining the sealing function with other functions
• CPC Class Codes: F16J 15/14 by means of granular or plastic material, or fluid
• CPC Class Codes: H05K 9/0015 Gaskets or seals
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31605 Next to free metal
• CPC Class Codes: Y10T 428/31609 Particulate metal or metal compound-containing
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]

Abstract

A form in place conductive gasket is disclosed. The gasket, foamed, gelled or unfoamed is made of one or more elastomer resins, such as silicone urethane and/or thermoplastic block copolymers and is either filled with a conductive filler and lined onto a desired substrate or lined onto the substrate unfilled and then coated with a conductive outerlayer, such as a silver filled elastomer or a conductive flocked layer. A process and system for making the gaskets are also disclosed.

Claims

1. An EMI gasket consisting essentially of

a polyester having isocyanate of trialkoxy silyl end groups capable of chemically reacting with each other at room temperature in the presence of moisture to form a derivative polymer having a longer chain length than the polyester;

and

at least one electrically conductive filler intimately mixed with the derivative polymer to form a composition which, when maintained in the absence of moisture and other hydrogen donor materials, is a readily extrudable and otherwise conventionally moldable thermoplastic material which, upon exposure to moisture at room temperature, becomes essentially thermosetting,

said gasket having a Shore A hardness of from about 5 to about 60, a force/deflection value of from about 0.2 pounds/inch to 15.0 pounds/inch, an electrical resistance value of from about 0.005 ohms to 0.1 ohms, a compression set value of from about 5% to about 50%, and an EMI shielding effectiveness of from about 10 dbs to about 120 dbs at a frequency range of from about 10 MHz to about 10 GHz.

2. The gasket according to claim 1, wherein the gasket has a shore A hardness of from about 5 to about 50.

3. The gasket according to claim 1, wherein the gasket has a shore A hardness of from about 5 to about 40.

4. The gasket according to claim 1, wherein the gasket has a diameter of form about 0.01 inches to about 0.025 inches.

5. The gasket according to claim 1, which also includes a noncross-linked elastomer that is not substantially chemically reactive with itself and with said primary polymer.

6. The gasket of according to claim 1, wherein the electrically conductive filler is selected from the group consisting of noble metal fillers, noble metal-plated noble metals, noble metal plated non-noble metals, noble metal-plated glass, noble metal-plated plastic, noble metal-plated ceramics, noble metal-plated mica, non-noble metals, non-noble metal-plated non-noble metals, carbon black, and graphite.

7. An EMI gasket comprising

a polyester having isocyanate or trialkoxysilyl end groups capable of chemically reacting with each other at room temperature in the presence of moisture to form a derivative polymer having a longer chain length than the polyester;

and

at least one electrically conductive filler intimately mixed with the derivative polyester to form a composition which, when maintained in the absence of moisture and other hydrogen donor materials, is a readily extrudable and otherwise conventionally moldable thermoplastic material which, upon exposure to moisture at room temperature, becomes essentially thermosetting.