Heat shrinkable electromagnetic shield for electrical conductors

Claim 2

An article according to claim 1 in which metal particles are not larger than 0.7 Tm in any dimension.

Claim 3

An article according to claim 3 in which the metal particles are selected from the class of noble metals.

Claim 4

An article according to claim 4, in which the metal particles are silver.

Claim 5

An article according to claim 1, in which the first tubular wall is substantially more shrinkable radially than lengthwise.

Claim 6

An article according to claim 1, in which the polymeric matrix contains 25 to 35 volume percent of conductive metal particles.

Claim 7

An article according to claim 1, in which the resistance of the second tubular wall is less than About 150 ohms per foot of length.

Claim 8

An article according to claim 8 in which the second tubular wall is bonded to the inside of the first tubular wall.

Claim 9

An article according to claim 9 in which the metal particles are less than 0.7 Tm in their largest dimension, and in which the heat shrinkable material is a cross-linked polymer.

Claim 10

An article according to claim 10 in which the metal particles are silver and in which the second tubular wall is a polyolefin.

Claim 11

An article according to claim 10 in which the second tubular wall is selected from the class consisting of a polyamide resin, silicone resin and polybutadiene-styrene resin.

Claim 12

An article according to claim 12 in which the first tubular wall is polyethylene.

Claim 13

An article according to claim 9 in which the metal particles are silver and have a maximum dimension of 0.7 Tm in any dimension.

Claim 14

An article according to claim 14 in which the second tubular wall is a polyamide.

Claim 15

An electromagnetic shielding article adapted to be shrunk comprising a first tubular wall of heat-shrinkable plastic material and a second tubular wall of flexible and resilient polymeric matrix having electrically conductive metal particles therein, said second tubular wall bonded to and conforming to the shape of the first tubular wall, the thickness of the second tubular wall being between 0.5 and 10 mils, the first tubular wall having a shrink ratio Sr between 7 and 1.1, and the polymeric matrix contains between about 20 to 40 volume percent of conductive metal particles, in the above Sr is defined as Do/Df where Do is the original inside diameter of the first tubular wall and Df is the final inside diameter of the first tubular wall after article is shrunk.

Claim 16

An article according to claim 16 in which the resistence of the second tubular wall prior to shrink is less than about 150 ohms per foot of length.

Claim 17

An article according to claim 16 in which the second tubular wall is bonded to the inside of the first tubular wall.

Claim 18

An article according to claim 18 in which the second tubular wall is selected from the class consisting of polyamide, silicone and polybutadiene-styrene resins.

Claim 19

An article according to claim 19 in which the metal particles are silver and wherein the silver particles are less than seven-tenths the thickness of the second tubular wall in any dimension.

Claim 20

An article according to claim 16 in which the second tubular wall is bonded to the inside of the first tubular wall, and in which the first tubular wall is substantially more shrinkable radially than lengthwise.

Claim 21

An article according to claim 19 in which the polymeric matrix contains 25 to 35 volume percent of conductive metal particles.

Claim 22

An article according to claim 22 in which the second tubular wall is a polyamide resin and the metal particles are silver.

Claim 23

An article according to claim 19 in which the maximum dimension of the metal particles is 0.1 Mu to 10 Mu and wherein the particles are silver.

Claim 24

An article according to claim 24 in which the second tubular wall is a polyamide resin.

Claim 25

An article according to claim 25 in which the first tubular wall is polyethylene.

Claim 26

An electromagnetic shielding article adapted to be shrunk comprising a first tubular wall of heat-shrinkable plastic material and a second tubular wall of flexible and resilient polymeric matrix having electrically conductive metal particles therein, said second tubular wall bonded to and conforming to the shape of the first tubular wall, the thickness of the second tubular wall being between 0.5 and 10 mils, the first tubular wall having a shrink ratio Sr between 7 and 1.1, and the polymeric matrix containing an amount of conductive metal particles with the second tubular wall prior to shrinking having a resistance of less than about 150 ohms per foot of length and, after shrinking having a substantially decreased resistance less than about 5 ohms per foot of length and an attenuation of not less than about 30 db. at frequencies in the range of between 10 kHz. to 10 GHz., the cohesion of the polymeric matrix being less than the strength of the bond of the first tubular wall to the second tubular wall, in the above Sr is defined as Do/Df where Do is the original inside diameter of the first tubular wall and Df is the final inside diameter of the first tubular wall after the article is shrunk.

Claim 27

An electromagnetic shielding article according to claim 27 in which the polymeric matrix contains about 20 to 40 volume percent of conductive metal particles.

Claim 28

An electromagnetic shielding article according to claim 27 in which the second tubular wall is bonded to the inside of the first tubular wall and the metal particles are silver.

Claim 29

An electromagnetic shielding article according to claim 29 in which the polymeric matrix is polyamide resin and in which the resistance of the second tubular wall after shrinking is less than 1.5 ohms per foot of length.