Flexible graphite composite sheet and method

• US 5,985,452 A
• Filed: 03/18/1997
• Issued: 11/16/1999
• Est. Priority Date: 03/18/1997
• Status: Expired due to Term

• Current Assignee: UCAR Graph-Tech Incorporated
• Original Assignee: Ucar Carbon Technology Corporation
• Inventors: Mercuri, Robert Angelo
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Bahta, Abraham
• Application Number:
  US08/819,744
• Time in Patent Office: 973 Days
• Field of Search: 428/913, 428/408, 428/323, 428/411.1, 428/920, 428/409, 264/113, 264/115, 423/448, 423/449.3, 423/460, 427/180
• US Class Current: 428/408
• CPC Class Codes: C04B 14/024 Graphite
• CPC Class Codes: C04B 20/002 Hollow or porous granular materials
• CPC Class Codes: C04B 2111/285 Intumescent materials
• CPC Class Codes: C04B 30/00 Compositions for artificial stone, not containing binders
• CPC Class Codes: C04B 35/522 Graphite C04B35/536 takes precedence
• CPC Class Codes: C04B 35/536 based on expanded graphite or complexed graphite
• CPC Class Codes: C04B 38/08 by adding porous substances
• CPC Class Codes: C09K 2200/0208 Carbon
• CPC Class Codes: C09K 3/1003 Pure inorganic mixtures
• CPC Class Codes: F16J 15/102 characterised by material
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10S 428/92 Fire or heat protection feature
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31 Surface property or characteristic of web, sheet or block
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

Flexible graphite sheet is made by compressing a mixture of fine particle of intercalated, exfoliated, expanded natural graphite with fine particles of intercalated, unexpanded, expandable particles of natural graphite, the unexpanded particles being more finely sized than the expanded particles. The resulting sheet of flexible graphite exhibits improved fire retardant and sealability properties.

Claims

1. A flexible graphite roll-pressed sheet of a blended mixture of (i) exfoliated expanded natural graphite particles formed of heat expanded intercalated natural graphite flake sized at least 80% by weight 20 by 50 mesh prior to heat expansion and (ii) unexfoliated intercalated natural graphite flake sized at least 80% by weight 50×

80 mesh, the amount of the unexfoliated intercalated natural graphite flake in the blended mixture and in the flexible sheet being from 5 to 25% by weight and said unexfoliated intercalated natural graphite flake being uniformly entrapped and surrounded in a continuous matrix of exfoliated natural graphite particles.