Gasket material

• US 5,240,766 A
• Filed: 04/01/1992
• Issued: 08/31/1993
• Est. Priority Date: 04/01/1992
• Status: Expired due to Fees

• Current Assignee: Hollingsworth & Vose Company
• Original Assignee: Hollingsworth & Vose Company
• Inventors: Foster, Richard P.
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): EDWARDS, NEWTON O
• Application Number:
  US07/861,477
• Time in Patent Office: 517 Days
• Field of Search: 428/280, 428/283, 428/284, 524/2, 524/16, 524/34, 524/35, 524/369, 264/109
• US Class Current: 428/297.4
• CPC Class Codes: C09K 2200/0282 Carbon fibres
• CPC Class Codes: C09K 2200/061 Butyl rubber
• CPC Class Codes: C09K 2200/0612 Butadiene-acrylonitrile rubber
• CPC Class Codes: C09K 2200/0647 Polyepoxides
• CPC Class Codes: C09K 2200/0685 Containing silicon
• CPC Class Codes: C09K 2200/0695 Polyamide fibres
• CPC Class Codes: C09K 3/1028 Fibres
• CPC Class Codes: D04H 1/43835 Mixed fibres, e.g. at least two chemically different fibres or fibre blends
• CPC Class Codes: D04H 1/58 by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives in combination with needling D04H1/488
• CPC Class Codes: Y10S 277/936 Composite
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/249949 Two or more chemically different fibers
• CPC Class Codes: Y10T 428/249951 Including a free metal or alloy constituent
• CPC Class Codes: Y10T 428/31678 Of metal
• CPC Class Codes: Y10T 428/31696 Including polyene monomers [e.g., butadiene, etc.]
• CPC Class Codes: Y10T 428/31699 Ester, halide or nitrile of addition polymer

Abstract

A composite gasket material includes a fiber component (3-15% by wt.), an elastomeric binder component (3-15% by wt.), and a solid filer component (60-90% by wt.). The material may additionally include a phenolic or epoxy resin (up to 5 wt. %) and a silicone resin (up to 5 wt. %). The filler includes as a component a salt formed from a multivalent metal cation and a sterically hindered dicarboxylic acid. The salt ingredient typically comprises from about 20 to 80 wt. % of the filler. Gaskets made from this composite material exhibit improved sealability and thermal stability while retaining other desirable mechanical properties. These materials are able to withstand operating temperatures up to about 450° C.

Claims

1. A gasket composition, comprising:

a fibrillated or nonfibrillated fiber component, having thermal stability at temperatures at least as high as 200°

C., and selected from the group consisting of natural fibers, carbon fibers, synthetic fibers and mineral fibers;

a filler component wherein at least 20 percent by weight of the filler comprises a salt of a multivalent metal cation and a sterically hindered dicarboxylic acid; and

an elastomeric binder component,

the gasket material demonstrating good sealability properties and a thermal stability at temperatures at least as high at 250°

C.

2. The composition of claim 1 wherein the fiber component is selected from the group of consisting of cellulosics, polyamides, polyaramids, acrylics, polyesters, polybenzimidazole, polyphenylene sulfide, polyimides, mineral fibers, carbon fibers, and mixtures thereof.

3. The composition of claim 2 wherein the fiber component comprises 3 to 15 percent by weight of the composition.

4. The composition of claim 1 wherein the metal cations are divalent and are selected from the group consisting of barium, cadmium, calcium, cobalt, magnesium, lead, nickel, strontium and zinc.

5. The composition of claim 4 wherein the hindered dicarboxylic acids are selected from the group consisting of terephthalic acid and isophthalic acid, tetrafluoro terephthalic acid, and 1,4-dicarboxy napthalene.

6. The composition of claim 5 wherein the filler component further comprises solids selected from the group consisting of attapulgates, clays, kaolins, talcs, magnesium hydroxide, alumina, mica, graphite, diatomaceous earths, aluminum trihydrate, zinc borate, and mixtures thereof.

7. The composition of claim 6 wherein the filler component comprises about 60 to 90% by weight of the composition.

8. The composition of claim 7, wherein the salt of the filler component is present at about 20 to 80% by weight of the filler component.

9. The composition of claim 2 wherein the binder component is present at about 3 to 15 percent by weight of the composition.

10. The composition of claim 9 wherein the binder is an elastomeric material selected from the group consisting of ABS rubbers, nitrile butadiene rubbers, hydrogenated nitrile butadiene rubbers, carboxylated nitrile butadiene rubbers, styrene butadiene rubbers, polyisoprene rubber, natural rubbers, butyl rubber, EPDM, polybutadiene rubbers, acrylic rubbers, and silicone rubbers.

11. The composition of claim 2 further comprising a polymeric material selected from the group consisting of epoxy resin and phenolic resin, present at up to 5% by weight.

12. The composition of claim 11, further comprising a silicone resin present at up to 5% by weight.

13. A composite gasket material having relatively high thermal stability, comprising

a fibrillated fiber component, present at about 3 to 15 percent by weight of the total composition;

an elastomeric binder composition, present at about 3 to 15 percent by weight of the total composition;

a filler component, present at about 70 to 90 percent by weight of the total composition, wherein at least 30 percent by weight of the filler comprises a salt of a divalent metal and a hindered dicarboxylic acid where the divalent metal is selected from the group consisting of barium, calcium, magnesium and zinc and the hindered dicarboxylic acid is selected from the group consisting of terephthalic acid and isophthalic acid, tetrafluoro terephthalic acid, and 1,4 dicarboxy napthalene;

a phenolic or epoxy resin present at up to 5% by weight; and

a silicone resin present at up to 5% by weight.

14. The material of claim 13 wherein the fiber component is selected from the group consisting of cellulosics, polyamides, polyaramids, polyesters, acrylics, polyimides, polybenzimidazole, polyphenylene sulfide, carbon fibers, glass fibers, ceramic fibers, and mixtures thereof.

15. The material of claim 14 wherein the elastomeric binders are selected from the group consisting of nitrile butadiene rubbers, hydrogenated nitrile butadiene rubbers, carboxylated nitrile butadiene rubbers, acrylic rubbers, silicone rubbers, butyl rubber, EPDM, styrene butadiene rubbers, polyisoprene rubbers, natural rubbers, and polybutadiene rubbers.

16. The material of claim 15 wherein the gasket material is able to provide sealing properties and to withstand thermal degradation at temperatures up to about 450°

C.

17. The material of claim 13 having resistance to degradation by oils, fuels, alcohols and diols.