Electromagnetic shielding

Claim 2

An electromagnetic energy shielding material having a volume resistivity to be effective as an electromagnetic energy shield, said material comprising a resin matrix loaded with electrically conductive, irregularly shaped particles, said particles comprising an aluminum core having a first layer of tin and a second layer of silver on said first layer.

Claim 3

The material of claim 1 in which said composition is in the form of a coating, caulking compound or adhesive,

Claim 4

The material of claim 1 in which the composition is in the form of a form stable sheet or molded article.

Claim 5

The material of claim 1 in which the composition is compressible and in the form of a form stable gasket.

Claim 6

The material of claim 1, 2, 3, or 4 in which said first layer comprises 1 to 10% by weight of said particles and said second layer comprises 10 to 25% by weight of said particles.

Claim 7

The material of claim 1, 2, 3, or 4, in which said particles comprises 20 to 50% volume percent of the material.

Claim 8

The material of claim 1, 2, 3, or 4, in which the average particle size is 1 to 60 microns and the volume resistivity is less than 0.01 ohm cm.

Claim 9

The gasket of claim 7 in which said particles comprise 3 to 8% by weight of said first layer of tin and 10 to 25% by weight of said second layer of silver and the reminder of the weight of the particles being aluminum core.

Claim 10

The material of claim 1, 2, 3, or 4, in which the resin matrix is silicone or flurosilicone rubber.

Claim 11

A compressible electromagnetic energy gasket having a volume resistivity to be effective as an electromagnetic energy shield comprising a compressible resin matrix loaded with irregularly shaped particles, said particles comprising an aluminum core having a first layer of tin, and a second layer of silver on said first layer.

Claim 12

A compressible electromagnetic energy gasket having a volume resistivity to be effective as an electromagnetic energy shield comprising a compressible resin matrix loaded with irregularly shaped particles, said particles comprising an aluminum core having a first layer of tin, and a second layer of silver on said first layer.

Claim 13

The material of claim 10 in which the first layer comprises 3 to 8% by weight of the particles and the second layer comprises 10 to 25% by weight of the particles.

Claim 14

A material having a volume resistivity to be effective as an electromagnetic energy shield comprising a resin matrix loaded with irregularly shaped particles, said particles comprising an aluminum core, a first layer of nickel on said aluminum and a second layer of silver on said first layer.

Claim 15

A material having a volume resistivity to be effective as an electromagnetic energy shield comprising a resin matrix loaded with irregularly shaped particles, said particles comprising an aluminum core, a first layer of nickel on said aluminum and a second layer of silver on said first layer.

Claim 16

The material of claim 12 or 11 in which the average particle size is 1 to 60 microns and the volume resistivity is less than 0.01 ohm cm.

Claim 17

The material of claim 12, or 11 in which the particles comprise 20 to 50 volume percent of the material.

Claim 18

A material having a volume resistivity to be effective as an electromagnetic energy shield comprising a resin matrix loaded with irregularly shaped particles, said particles comprising an aluminum core, a first layer of zinc on said aluminum and a second layer of silver on said first layer.

Claim 19

A material having a volume resistivity to be effective as an electromagnetic energy shield comprising a resin matrix loaded with irregularly shaped particles, said particles comprising an aluminum core, a first layer of zinc on said aluminum and a second layer of silver on said first layer.

Claim 20

The material of claim 15 in which the first layer comprises 1 to 10% by weight of the particles and the second layer comprises 10 to 25% by weight of the particles.

Claim 21

The material of claim 15 or 16 in which the average particle size is 1 to 60 microns and the volume resistivity is less than 0.01 ohm cm.

Claim 22

The mateial of claim 15 or 16 in which the particles comprise 20 to 50 volume percent of the material.

Claim 23

The material according to claim 8 or 16 in which the weight of the first layer is 3 to 8%.

Claim 24

The material of claim 12 or 15 in the form of a form stable gasket, coating, caulking compound or adhesive.

Claim 25

An electromagnetic energy shield having a volume resistivity to be effective as an electromagnetic energy shield, said shield having a resin matrix with electrically conductive irregularly shaped particles dispersed therein, said particles comprising an outer surface of silver on a sensitizing layer of tin which is on an aluminum central core, said tin being present on said aluminum in an amount sufficient to provide a surface to which the silver may be placed thereon, said particles having the ability to withstand 120° C. for 120 hours without exhibiting substantial loss in conductivity.

Claim 26

An electromagnetic energy shield having a volume resistivity to be effective as an electromagnetic energy shield, said shield having a resin matrix with electrically conductive irregularly shaped particles dispersed therein, said particles comprising an outer surface of silver on a sensitizing layer of tin which is on an aluminum central core, said tin being present on said aluminum in an amount sufficient to provide a surface to which the silver may be placed thereon, said particles having the ability to withstand 120° C. for 120 hours without exhibiting substantial loss in conductivity.

Claim 27

The shield of claim 21 in which the silver is plated on the sensitizing tin layer.

Claim 28

The shield of claim 21 in which the resin is silicone.

Claim 29

An electromagnetic energy shield having a volume resistivity to be effective as an electromagnetic energy shield, said shield having a resin matrix with electrically conductive irregularly shaped particles dispersed therein, said particles comprising an outer surface of silver on a sensitizing layer of zinc which is on an aluminum central core, said zinc being present on said aluminum in an amount sufficient to provide a surface to which the silver may be placed thereon, said particles having the ability to withstand 120° for 120 hours without exhibiting substantial loss in conductivity.

Claim 30

An electromagnetic energy shield having a volume resistivity to be effective as an electromagnetic energy shield, said shield having a resin matrix with electrically conductive irregularly shaped particles dispersed therein, said particles comprising an outer surface of silver on a sensitizing layer of zinc which is on an aluminum central core, said zinc being present on said aluminum in an amount sufficient to provide a surface to which the silver may be placed thereon, said particles having the ability to withstand 120° for 120 hours without exhibiting substantial loss in conductivity.

Claim 31

The shield of claim 24 in which the silver is plated on the sensitizing zinc layer.

Claim 32

The shield of claim 24 in which the resin is silicone.