Protecting wool

Shimizu and Oku (1957) studied the effects of salts on the solubility of wool in 0.1 M KOH. At low salt concentrations the effects of various ions followed the Hofmeister series. Similarly, McPhee (1958b, 1959) has shown that whereas 56 % of wool was dissolved by 1.286 N NaOH at 25°C in 2 hr, only 2 % dissolved when the solution was first saturated with NaCl. There was a corresponding decrease in formation of primary amino groups and in loss of cystine. Not all salts were equally effective in protecting wool against alkali damage. The effectiveness of 2 M solutions of the sodium salts decreased in the order 8203 > SO3 > citrate > COs" > SO 4 > acetate > Cl > Br > NOs" > I > CNS . Cations followed the order Li+, Na+ > K+. Similar rates of alkali uptake were obtained with all salts at a concentration oi 2 M. 

Such crosslinks would be expected to Increase the Internal viscosity within the fiber, thereby decreasing the rate at which setting Is lost In hot water. This hypothesis was tested by Caldwell et al. ( ) who compared the crease recoveries of wool fabrics treated with aqueous formaldehyde or formaldehyde vapors with those of untreated fabrics. They found that the treatments enhanced the set through Introduction of crosslinks that Inhibited the rearrangement of disulphide bonds In the wool. Kann (9,10) noted that formaldedye treatment protected wool against alkali... 

Llpson, M., and Hope, R.J. (1955). Use of dleldrln to protect wool against Insect attack. Nature, 175, 599-600. 

Formaldehyde Treatment of Wool. The impioved resistance of formaldehyde treated wool to the action of boiling Yate, alkalis, alkali sulfides, etc., may be utilized to protect wool in processes such as bleaching, dyeing, washing, etc., which in% olve exposure to these agents. In a process patented by Kaon in 1905, it is stated that satisfactory resistance of woolen fibers can be developed by treatment with foimaldehyde apors or dilute neutral or weakly acid solutions containing as little as 0.03 per cent formaldehyde. Ciood results ai e reported when a hot 4 per cent formaldehyde solution is employed. 

Fig. 77,13, 1 illustrates a distillation unit when it is desired to protect the distillate from moisture in the atmosphere. The drying tube may be filled with anhydrous calcium chloride held in position by loose plugs of glass wool or with a loose plug of cotton wool. Fig. 77,13, 2 depicts the use of an air condenser for liquids of boiling point above 140-150°. 

When the adsorbent has been introduced into the tube, the latter is fitted into a filter flask (see Fig. 77, 46, 2) to which a pump is attached the pump is run slowly and the column is again pressed down gently with the wooden pestle. The circumference of the upper surface is gently and uniformly tapped, especially where it is in contact with the glass surface, for about one minute air bubbles and channels are thus avoided when the solution is poured in. Some workers place a loose plug of cotton wool or a circle of filter paper at the top of the column in order to protect the solid from disturbance when the liquid is introduced. 

Method B. In a 500 ml. round-bottomed flask, provided with a reflux condenser protected by a cotton wool (or calcium chloride) drying tube, place 59 g. of succinic acid and 102 g. (94-5 ml.) of redistilled acetic anhydride. Reflux the mixture gently on a water bath with occasional shaking until a clear solution is obtamed ca. 1 hour), and then for a further hour to ensure the completeness of the reaction. Remove the complete assembly from the water bath, allow it to cool (observe the formation of crystals), and finally cool in ice. Collect the succinic anhydride as in Method A. The yield is 45 g., m.p. 119-120°. 

The diazomethane-ether solution should be dry. If in doubt, it may be dried with A.R. potassium hydroxide pellets. The anhydrous ethereal solution may be stored in a smooth glass flask or bottle in a refrigerator for a week or so since slow decomposition occurs with hberation of gas, the containing vessel should be protected by a calcium chloride (or cotton wool) guard tube. 

Iodine monochlorlde may be prepared as follows. Pass dry chlorine into 127 g. of iodine contained in a 125 ml. distilling flask until the weight has increased by 34-6 g. The chlorine should be led in at or below the surface of the iodine whilst the flask is gently shaken it is essential to have an excess of iodine. Distil the iodine chloride in an ordinary distillation apparatus use a filter flask, protected from atmospheric moisture by a calcium chloride (or cotton wool) guard tube, as a receiver. Collect the fraction b.p. 97-105° the jdeld is 140 g. Preserve the iodine monochloride in a dry, glass-stoppered bottle. 

Fig. 1. Schematic of the cross section of a mammal s skin. The relative size and function of the parts depend on the species and breed of the animal. For goats, where the wool or hair is sparse because it is not needed for warmth, the skin is dense to provide protection for sheep protected primarily by heavy wool, the skin contains more oil (sebaceous) glands to lubricate the wool for catde, both the hair and the heavy hide stmcture protect the animal (3).

Sheep and fur animals are protected primarily by their wool or hair. The fiber stmcture of the skin is very fine and has less strength than calfskin or other nonfur mammals. The sheepskin has a high concentration of hair foUicles and sebaceous glands. When taimed the fur skin has an open stmcture, is soft, and lacks strength relative to many other leathers. 

Wool belongs to a family of proteins, the keratins, that also includes hair and other types of animal protective tissues such as horn, nails, feathers, and the outer skin layers. The relative importance of wool as a textile fiber has declined over the decades as synthetic fibers have increa singly been used in textile consumption. Wool is still an important fiber in the middle and upper price ranges of the textile market. It is also an extremely important export for several nations, notably AustraUa, New Zealand, South Africa, and Argentina and commands a price premium over most other fibers because of its outstanding natural properties of soft handle (the feel of the fabric), moisture absorption abiUties (and hence comfort), and superior drape (the way the fabric hangs) (see Fibers Textiles). Table 2 shows wool production and sheep numbers in the world s principal wool-producing countries. 

Wool fibers consist of cells, where battened ovedapping cuticle cells form a protective sheath around cortical cells. In some coarser fibers, a central vacuolated medullary cell type may be present. 

In fine wool such as that obtained from merino sheep, the cuticle is normally one cell thick (20 x 30 x 0.5 mm, approximate dimensions) and usually constitutes about 10% by weight of the total fiber. Sections of cuticle cells show an internal series of laminations (Figs. 1 and 2) comprising outer sulfur-rich bands known as the exocuticle and inner regions of lower sulfur content called the endocuticle (13). On the exposed surface of cuticle cells, a membrane-like proteinaceous band (epicuticle) and a unique hpid component form a hydrophobic resistant barrier (14). These hpid and protein components are the functional moieties of the fiber surface and are important in fiber protection and textile processing (15). 

In devising strategies to prevent insect attack on processed woolens, it is appropriate to aim only to protect processed wool goods and to control the principal domestic pest species. This is usually achieved by incorporation of an insecticide into those goods required to be protected, usually from the dyebath while the articles are being dyed, and methods for protection of wool goods have been reviewed (122). 

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