Casein fibres

Casein is used for a number of miscellaneous purposes in which foimolisation is not required. These include adhesives, stabilisers for rubber latex, paper finishing agents and miscellaneous uses in the textile industry. Mention may also be made of casein fibres, available in Italy between the two world wars under the name of Lanital. 

Edible casein fibres (Section 12.17) can be obtained by spinning an aqueous solution or slurry of a casein salt into a coagulating bath, or directly into the air [84]. 

Casein fibres can be made by dissolving casein in an alkaline solntion and extrnding throngh fine nozzles into an acid-coagulating bath, followed by treatment with formaldehyde to reduce water penetration. 

From Williams S. and Tonn W.H., Qualitative methods of identifying soybean fibres in mixtures of casein fibre, wool or other textile fibre. Rayon Textile Monfh/y September, 63-64 (523-524), 1941. 

Acid casein finds use in a variety of applications, including adhesives (mainly for paper and wood) and paper coatings. In these latter uses, the casein is applied as a dispersion in aqueous alkali. Casein fibre may be produced by forcing an alkaline dispersion through a spinneret into an acid coagulating bath the fibre (commonly termed casein woof) was produced commercially during World War II in Italy and the U.S.A. but it is now of little importance. Acid casein is used rather than rennet casein in these various applications since it is more readily dispersed in aqueous alkali. 

Synthetic fibres made from proteins are Aralac from milk protein casein, Vicara from corn protein zein, and Saralon from peanut protein. These fibres look like wool and can also be dyed just like wool or silk is dyed. These fibres are blended with wool to add strength. 

Jimenez-Colmenero, F., Ayo, M.J., and Carballo, J. (2005). Physicochemical properties of low sodium iraiikfurler with added walnut effect of transglutaminase combined with caseinate, KCl and dietary fibre as salt replacers. Meat Science, 69,781-788. 

The raw materials used for the preperation of regenerated protein fibres may be milk, soyabeans, peanuts and zein. Sometimes alkaline solutions of gelatin, albumin and other raw materials like waste wool, silk and feathers may be used. Fibrolane (Great Bretain) and Merineva (Italy) are made by dissolving casein in sodium hydroxide, and then by extrusion into an acid/saltbath. The fibres formed in this way... 

Casein/cellulosic fibre blended fabric is first desized under mildly acidic conditions at 60-70 C for 30-60 min and then scouring is carried out in a fresh bath at pH 6 with 3-4 g/1 non-ionic detergent at 50-60°C for 30 min, and rinsed well, first in warm and then in cold water. 

The success of the regenerated cellulosic fibres stimulated the imagination of chemists. The obvious sequel was to produce a regenerated protein with properties resembling wool or silk. Much research and capital expenditure has been devoted to the production of lanital from milk casein, ardil from ground-nut protein, saran from soya bean, and vicara from maize. None of them proved really commercially successful and their manufacture has now virtually ceased. 

Another important branch of the Italian chemical industry was that of fibres, such as artificial silk derived from cellulose and a casein-based fibre called Lanital. Their dynamic development partially replaced the traditional textiles as a leading export industry, while artificial fibres also replaced significantly cotton, wool and jute imports. More than 80 per cent of the overall output was produced by SNIA Viscosa and CISA Viscosa, two associated firms dominated by the same network of interlinked... 

Cellulose-based plastics, particularly cellulose nitrate and acetates, were the most commercially important semi-synthetics up to the 1940s and were used as the base for photographic film, textile fibres, moulded goods and in lacquers. Naturally occurring polymer cellulose in the form of cotton linters or wood pulp is chemically treated to increase its solubility. Cellulose has a high molecular weight of between 100000 and 500000 and an empirical formula C0H1OO5. Casein-formaldehyde is the only protein-based moulded plastic that achieved commercial success. It is based on cow s milk and is still produced in very small quantities for specialist items such as hand-coloured buttons. 

Chemical bonding. A binder such as glue, rubber, casein, latex, cellulose derivative, or a synthetic resin is used for bonding the filaments or short fibres together and these materials are known as chemically or adhesive bonded nonwoven geotextiles. 

The first macromolecular substances which fotmd technical interest were based on chemically modified natural materials, for example cellulose nitrate (Celluloid) or crosslinked casein (Galalith). Only with the onset of industrialisation in the nineteenth century did these renewable raw materials become the limiting factor for further growth, and chemists began developing artificial macromolecules based on fossil carbon sources like coal, oil, and gas. Polymers like condensation products from phenol and formaldehyde (Bakelite) started the plastics age in 1910 and polymers of styrene or vinyl chloride were used since about 1930 and until nowadays as important plastics. Presently, worldwide more than 260 million tons polymers per year are produced and used as plastics, films, fibres, and synthetic rubber. 

Advantages over wool are claimed to be (a) more uniform stmctnre, (b) sconring not reqnired and (c) high affinity for dyestuffs. Disadvantages are loss of strength (np to 50%) on wetting and poor resistance to bacterial attack. Such regenerated fibres have not yet proved to be commercially successful as textiles but show more promise in the field of simulated meat products (Section 12.4) [10]. The co-extrusion of casein and cellulose has been tried [11]. 

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