Water soluble fibres

Water soluble fibre processing aid which imparts low fibre to metal and medium to high fibre to fibre friction together with good antistatic properties. DRAFCOL S6H is recommended for use on man-made fibres and their blends on a wide variety of processing systems. 

Pandey, M., and A. Khan. 2002. H) oglycaemic effect of defatted seeds and water soluble fibre from the seeds of Syzygium cumini (Linn.) Skeels in aUoxan diabetic rats. Indian. Exp. Bid. 40(10) 1178-1182. 

Catechins are water-soluble however, they can be rendered insoluble by chemical reaction (Yayabe, 2001). Insoluble catechins do not lose their phenol hydroxyl groups, and their anti-bacterial and deodorising actions remain almost unaffected. In this form they are useful as natural anti-bacterial and deodorising materials for application to fibres and plastics. 

Figure 2 Ion-exchange chromatography on DEAE-Sepharose CL-6B (elution by acetate buffer pH 4.8) of (a) dialysed water-soluble pectins from extruded citrus fibres (SME = 250 kWh/t) and (b) dialysed acid extracted pectins from the same raw material, (empty symbols neutral sugars full symbols= galacturonic acids)...

The results showed (16) that the extruded products contained a large amount of water soluble pectins of high molecular weight which were able to gel. It has been shown that the all the extruded citrus fibres were able to gel in presence of sucrose at acidic pH without prior extraction of the pectins. 

The traditional use of dyes is in the coloration of textiles, a topic covered in considerable depth in Chapters 7 and 8. Dyes are almost invariably applied to the textile materials from an aqueous medium, so that they are generally required to dissolve in water. Frequently, as is the case for example with acid dyes, direct dyes, cationic dyes and reactive dyes, they dissolve completely and very readily in water. This is not true, however, of every application class of textile dye. Disperse dyes for polyester fibres, for example, are only sparingly soluble in water and are applied as a fine aqueous dispersion. Vat dyes, an important application class of dyes for cellulosic fibres, are completely insoluble materials but they are converted by a chemical reduction process into a water-soluble form that may then be applied to the fibre. There is also a wide range of non-textile applications of dyes, many of which have emerged in recent years as a result of developments in the electronic and reprographic... 

Electrolytes are used to promote the exhaustion of direct or reactive dyes on cellulosic fibres they may also be similarly used with vat or sulphur dyes in their leuco forms. In the case of anionic dyes on wool or nylon, however, their role is different as they are used to facilitate levelling rather than exhaustion. In these cases, addition of electrolyte decreases dye uptake due to the competitive absorption of inorganic anions by the fibre and a decrease in ionic attraction between dye and fibre. In most discussions of the effect of electrolyte on dye sorption, attention is given only to the ionic aspects of interaction. In most cases, this does not create a problem and so most adsorption isotherms of water-soluble dyes are interpreted on the basis of Langmuir or Donnan ionic interactions only. There are, however, some observed cases of apparently anomalous behaviour of dyes with respect to electrolytes that cannot be explained by ionic interactions alone. 

Compared with wool and cotton, the scouring procedures for synthetic fibres are relatively simple since these fibres contain fewer impurities. Most of these have at least some degree of water solubility the most important are sizes and lubricants. The major sizes used are poly (vinyl alcohol), carboxymethylcellulose and poly (acrylic acid), all of which are completely or partially water-soluble. Sometimes aliphatic polyesters are used. 

The polyester sizes used have a much lower average molecular mass than polyester fibres. These structures (10.69) contain sulphonic acid groups and may be water-soluble or water-dispersible types. The degree of sulphonation is low [171]. If these resins are subjected to a high pH, the sulphonate groups can be hydrolysed, giving an insoluble resin that is very difficult to remove from the fibres. 

Poly (vinyl acetate/alcohol) sizes are also described as water-soluble and are widely used, either alone or in combination with most of the other types, across the whole range of fibres and blends [169,171]. However, this category covers a wide range of commercial products, differing greatly in quality and ease of removal. Indeed, some are quite difficult to remove, thus necessitating careful selection [187]. Detailed studies of factors affecting the removal of water-soluble sizes, particularly poly(vinyl alcohol) types, have been published [188-190]. 

Glass fibres are fragile and break easily because of surface defects. This is overcome by treating virgin fibres with water-soluble sizing agents. These protect... 

Retention and drainage aids are chemicals which are added to the fibre and filler suspension to assist the efficiency of the filtration process. Growth in recent years in the use of retention aids has been greater than that of almost any other paper chemical additive. It has been caused by a combination of factors increased machine speeds, the increased use of filler in alkaline systems, the increased use of recycled paper and the growing tendency to use fillers in newsprint. Retention aids are water-soluble polymers which may be cationic,... 

Simply impregnating paper with formaldehyde and drying gives some limited wet strength, but it also causes brittleness and suffers from the problem of odour. The condensation product of formaldehyde and urea, 1,3-dihydroxymethylurea (Figure 7.23), is also effective, but it is water soluble and not substantive to cellulosic fibres in aqueous suspension. 

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