Thursday, July 28, 2011

THE TEXTILE APPLICATION


      At the present time all the well known resins of the colourless type are employed in textile work for one purpose or another. The following brief survey is merely illustrative of the main types which the analyst may expect to find.
Many of the thermoplastic types are made into fibres.e g the poly amides polyvinyl chloride polyisobutylene chloride alkyd and styrene. There are three to four protein formaldehyde fibres .Some fibres ,especially cotton and rayon are reacted with synthetic resin components such as aldehyde or ketone to produce new cross bonded products exhibiting durable stiff finishes which must be regarded as belonging to the synthetic resin group  The treatment of cellulose with acetone and of wool with formaldehyde must be included in this group.

Starch has been condensed with formaldehyde in presence of an acid catalyst to produce resistant finishes. Cellulose ethers (alkyl celluloses ) including methyl ethyl and benzyl cellulose have useful applications . methyl cellulose has the peculiar and valuable property of being insoluble in hot water but soluble cold . The hydroxylate celluloses / such as glycol cellulose form mucilages with 2N caustic soda from which they can be applied to textiles . treatment with dilute acid precipitates the resin on to the fibre in a form fast to mild washing . Carboxymethyl cellulose forms a water soluble sodium salt which on drying on the fibre gives a flexible film type finish.

Cellulose will also condense with dimethylol form amide, H.co.N(C H 2 OH or a mixture of glottal urea formaldehyde to give cross bonded effects.
Animalised rayon is produced by incorporating phenol formaldehyde , Gaudiness formaldehyde melamine formaldehyde or cyan amide formaldehyde resins in the spinning bath for viscose to give such products as Hollandaise the cellulose being cross bonded . Non cross bonded types contain particles of E.G basis polyethylene mine resin as example being Sinistral.

Emulsion of many thermoplastic resins are applied followed by drying and possibly by heat treatment to give special finishes . Polyvinyl acetate polyvinyl alcohol and methyl meth acrylate (Possibly modified by alkyd resins 0 are used for abrasion resistant finishes . non snag finishes non slip finishes therm adhesive finishes permanent embossed effects and pigment fixation in printing. They may be produced using either an anion active emulsifier for padding purposes or with a cation active emulsifier in which axes the emulsified resin is substantive to the fibre.

Amongst thermosetting resins urea formaldehyde types are used for crease resistant finishes being applied in a partly preformed state and subsequently cured by baking . A partly preformed resin alkyd modified may be applied from an ammonia solution dried and baked to give permanent stiff finishes . Urea formaldehyde resins partly condensed to a water soluble product may be produced as water soluble powders the solutions of which give a finely dispersed and substantive precipitate of methylene urea polymer on addition of acid these products are used for de lustred finishes which are permanent after baking . Other de lustred effects are obtained by adding titanium oxide to an ordinary urea formaldehyde resin preparation. Thoreau may be used in place of urea.
The melamine resins are rapidly increasing in importance. Melamine formaldehyde resin anticancer finishes are more resistant to chlorine bleaching in laundering than the urea formaldehyde types on cotton .they have been used to produce shrink resistant finishes on wool. Discriminable formaldehyde resins are used to confer improved wash fastness on dyestuffs and are also claimed to impart fireproof properties .