The Wiggins Teape Group Limited

Ian S Biggs

Bronislaw Radvan

Andrew E Bayly

A foamed aqueous dispersion of a mixture of particulate plastics material is formed when the fibers are between 5% and 35% of the volume of the mixture, where no more than about 7% of the volume of the mixture is conductive fibers between about 7 and 20 mm long, and where any other fibers are reinforcing fibers with a high modulus of elasticity and between about 7 and about 50 mm long. A web is formed from the foamed dispersion using a wet laying process. The web is dried and compacted under heat and pressure. The compacted web is cooled to form a consolidated element in which the conductive fibers extend as a conductive lattice. The resulting element can be formed or molded into shielding to provide attenuation of electrical or magnetic fields.

Electromagnetic interference shielding

Laminated reinforced thermoplastic sheets are made by preparing first and second porous sheets, each having 20% to 60% by weight of reinforcing fibers having a high modulus of elasticity and 40% to 80% by weight of a thermoplastic material differing from the thermoplastic material in the other sheet and applying heat and pressure to cause the sheets to consolidate and adhere together to form the laminate.

Method of making laminated reinforced thermoplastic sheets and articles

A fibre reinforced thermoplastics material structure having a first layer which is fully consolidated with uniformly dispersed fibres and a second layer which is formed as an absorbent matrix.

Fibre reinforced thermoplastics material structure

An air permeable sheet-like structure comprising 5% to 50% by weight of reinforcing fibres, and between about 5 and about 50 millimeters long, and from 50% to 95% by weight of wholly or substantially unconsolidated particulate non-cross-linked elastomeric material, and in which the fibrous and elastomeric components are bonded into an air permeable structure.

Fibre reinforced plastics structures

An air permeable sheet-like structure comprising 20% to 60% by weight of single discrete reinforcing fibres having a high modulus of elasticity (as herein defined), and being between about 7 and about 50 millimeters long and 40% to 80% by weight of wholly or substantially unconsolidated elements of thermoplastics material, and in which the fibrous and thermoplastics components are bonded into an air permeable structure, at least some of said elements of thermoplastics material each having a first dimension of not more than 1 millimeters, a second dimension of between 1.5 millimeters and 30 millimeters, a total volume of not more than 30 cubic millimeters and a surface area to volume ratio greater than about 4:1, with any further elements of thermoplastics material present each having a volume of less than about 1.8 cubic millimeters.

Plastics material

A process for forming a homogeneous sheet from particulate elements, (as herein defined), at least some of which have an inherent vertical mobility (as herein defined) in water at normal temperature and pressure of from about 1 to about 21 cms/sec, which comprises the steps of forming a foamed dispersion of said particulate elements, and depositing and draining said dispersion on a foraminous support.

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High Wycombe, United Kingdom

Ian S Biggs