Viscose rayon shredding

Cuprammonium rayon is made from scoured and bleached cotton linters or purified wood pulp with a high a cellulose content. The cellulose is washed and then pressed until it contains about 50 per cent of water. In this state, it is placed in a mechanical mixer together with cuprammonium solution and agitated until completely dissolved, whilst the temperature is maintained at 5° C (41 °F). The solution is then diluted to about 10 per cent concentration. After filtration and exposure to vacuum to remove air bubbles and dissolved gases, the solution is allowed to ripen in enclosed vessels until it is the desired viscosity. In modem practice copper carbonate is mixed intimately with the cellulose in a shredding machine and the resultant mass is then broken up and stirred for some hours with aqueous ammonia and caustic soda, when it passes into solution. 

The first synthetic fiber for tires was rayon. Cellulose is initially treated with sodium hydroxide to form an alkali cellulose. It is then shredded and allowed to age in air, where it is oxidized and undergoes molecular weight reduction to enable subsequent spinning operations. Treatment with carbon disulfide produces cellulose xanthate, which is then dissolved in sodium hydroxide to form viscose. The material undergoes further hydrolysis and is then fed into spinnerets to produce the fiber. This fiber is passed through a bath of sulfuric acid and sodium sulfate, where the viscose fibers are further coagulated. 

After shredding, the alkali cellulose crumb is aged to obtain the DP for the type of rayon to be produced. Not only is the DP important to fiber properties, but it also affects the processing characteristics of the viscose. Solution viscosity is proportional to the DP and polymer concentration. Consequently, those fibers requiring a relatively high DP for reasons of strength must be made from viscose containing less cellulose [236]. 

Chem. Descrip. POE glycol ether block copolymer Uses Detergent emulsifier for emulsion polymerization improves and accelerates shredding and xanthation and improves clarity of viscose in rayon prod. emulsifier, dispersant for paints, pigments, dyes, printing inks... 

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