Microwave curing of uncured latex carpet

A method of making a floor covering comprising:

• tufting or implanting a fibrous material or yarn into a primary backing;
• precoating the underside of the primary backing layer by applying a precoating composition followed by microwave curing the precoating;
• applying a backing layer to the precoated primary backing layer;
• and
• if necessary curing the backing layer.

A method of making a floor covering comprising:

• coating a first layer of a thermoplastic resin plastisol on a support surface;
• optionally placing a dimensionally stable sheet material onto the top surface of the first layer and heating the layer to gel the layer and position the sheet material;
• optionally applying a second layer of a thermoplastic resin plastisol onto the gelled surface of the first layer;
• tufting or implanting a fibrous material or yarn into a primary backing material;
• precoating the underside of the primary backing and curing the precoating using microwaves;
• optionally coating a thermoplastic resin plastisol over the precoat layer;
• layering the precoated primary backing onto the top surface of the plastisol of the first or second thermoplastic resin layer to form a floor covering;
• heating the floor covering so formed to fuse the thermoplastic layers into an integrally-fused backing layer;
• cooling the flooring covering;
• and
• optionally cutting the floor covering into a carpet tile.

An apparatus for curing a precoated primary backing layer, the apparatus comprising:

• a microwave generator for generating microwaves;
• a single pass or multipass slotted waveguide applicator;
• and
• means for forwarding a primary backing layer having an uncured precoated provided thereon into the waveguide applicator.