The Wiggins Teape Group Limited

Peter Sinclair

Roger A Allen

David J Hasler

Neil Harvey Clifford

Angela J Hayes

Nicholas John Kite

Eileen H Burns

Casting paper of a desired surface texture or finish for use in the manufacture of artificial leather is produced by heating the polymer coating 1 of a polymer-coated paper 2 to a temperature sufficient to melt the polymer and then cooling the polymer coating from its molten state to a solid state as it passes through a nip between an embossing roll 3 having a surface configuration corresponding to said desired surface texture or finish and a backing roll 4, thereby to impart the surface configuration of the embossing roll to the polymer-coated paper. The polymer is preferably polyolefinic, for example poly (4-methyl-1-pentene) or a polypropylene/polyethylene blend. An anti-curl back-coat, for example of polyvinyl alcohol, can be applied after the embossing operation.

Casting paper

Aqueous suspensions of papermaking fibres and filler are each separately treated with an anionic or a cationic polymer, after which the filler (preferably) or the papermaking fibre is treated with a polymer of opposite charge to that used in the initial treatment. The filler and papermaking suspensions are then mixed to form a papermaking stock, with dilution as necessary before, during or after the mixing operation. This stock is then used to form a loaded paper web in conventional manner. The initial treating polymer is preferably a papermaking retention aid or flocculant, e.g. a cationic polyarcylamide or an amine/amide/epichlorohydrin copolymer in the case of cationic materials or an anionic polyacrylamide in the case of anionic materials. The further treating polymer is preferably an anionic or cationic starch, depending on the charge of the initial treating polymer.

Loaded paper

Paper coated uniformly with discrete dots of remoistenable adhesive, especially based on starch or polyvinyl alcohol, has curl stability comparable with particle gum coated papers. Preferably, the dots are less than 0.3 mm in diameter and typically spaced 0.5 to 1 mm (centers) apart. The product is made by screen coating dots of aqueous adhesive mix onto base paper.

Remoistenable adhesives

In a process for the production of microcapsules containing a liquid fill material, a dispersion-stabilizing species is produced in an aqueous acidic medium by interaction of a melamine formaldehyde precondensate and a water soluble polymer, neither of which alone is dispersion stabilizing with respect to the liquid fill material, and the precondensate is condensed by acid catalysis to produce a condensate which separates from solution and enwraps the liquid fill material to produce microcapsules.

Process for the production of microcapsules

Fibre recovery process for pressure-sensitive carbonless copying paper which comprises defibrating the wastage in aqueous media, preferably in the presence of a cationic quaternary ammonium surface active agent, treating the wastage with acid to destroy the microcapsules, and bleaching the defibrated wastage with a bleaching agent.

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Buckinghamshire, United Kingdom

Peter Sinclair