Viscose is a viscous organic liquid used to make rayon and cellophane. Viscose is becoming synonymous with rayon, a soft material commonly used in shirts, shorts, coats, jackets, and other outer wear.
At first wood pulp is dissolved in caustic soda (lye) and after steeping is shredded and allowed to age. Ageing contributes to viscosity and longer aging leads to greater viscosity. The aged pulp is then treated with carbon disulphide to form a yellow-colored cellulose xanthate, which is dissolved in caustic soda again, but of a lower concentration
Friday, August 6, 2010
Rayon fiber
Rayon is a manufactured regenerated cellulose fiber. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fiber nor a natural fiber; it is a semi-synthetic or artificial fiber. Rayon is known by the names viscose rayon and art silk in the textile industry. It usually has a high luster quality giving it a bright sheen.
Lyocell fiber process
Preparing the wood pulp Hardwood trees are harvested and trucked to the mill where they are cut to 20 ft (6.1m) lengths and debarked by high-pressure water jets. Next, the logs are chipped by a machine into squares about the size of postage stamps. The chips are digested chemically to soften them enough to be mechanically milled to a wet pulp. This pulp is washed with water, and may be bleached. Then it is dried into a continuous sheet and rolled onto spools. At this stage, it has the consistency of thick posterboard paper. The roll of cellulose weighs some 500 lb (227 kg).
Dissolving the cellulose At the Lyocell mill, several rolls of pulp are broken into one-inch squares and mixed with amine oxide in a heated, pressurized vessel.; the cellulose fibers begin to dissolve.
Filtering When the cellulose solution has become clear, it is pumped through filters to insure that all the chips are dissolved and to remove any remaining foreign material that would otherwise clog the spinners.
Spinning The solution is then pumped through spinnerets, devices used with a variety of manmade fibers. The spinneret is pierced with small holes rather like a showerhead; when the solution is forced through it, long strands of fiber come out. The fibers are then immersed in another solution of amine oxide, diluted this time, which sets the fiber strands. Then they are washed with de-mineralized water.
Drying and finishing The Lyocell fiber next passes to a drying area, where the water is evaporated from it. The strands then pass to a finishing area, where a lubricant, which may be a soap or silicone or other agent depending on the future use of the fiber, is applied. This step is basically a detangler, making the following steps of carding and spinning into yarn easier.
Final steps The dried, finished fibers are at this stage in a form called tow, a large untwisted bundle of continuous lengths of filament. The bundles of tow are taken to a crimper, a machine which compresses the fiber, giving it texture and bulk. The crimped fiber is carded by mechanical carders, which perform an action like combing, to separate and order the strands. The carded strands are cut and baled for shipment to a fabric mill. The entire manufacturing process, from unrolling the raw cellulose to baling the fiber, takes about two hours. After this, the Lyocell may be processed in many ways. It may be spun with another fiber, such as cotton or wool. The resulting yarn can be woven or knitted like any other fabric, and given a variety of finishes, from soft and suede-like to silky.
Recovery of the solvent The amine oxide used to dissolve the cellulose and set the fiber after spinning is recovered and re-used: the dilute solution is evaporated to remove the water, leaving amine oxide which is used for dissolving the next batch of cellulose. 98% of the amine oxide is typically recovered.
Dissolving the cellulose At the Lyocell mill, several rolls of pulp are broken into one-inch squares and mixed with amine oxide in a heated, pressurized vessel.; the cellulose fibers begin to dissolve.
Filtering When the cellulose solution has become clear, it is pumped through filters to insure that all the chips are dissolved and to remove any remaining foreign material that would otherwise clog the spinners.
Spinning The solution is then pumped through spinnerets, devices used with a variety of manmade fibers. The spinneret is pierced with small holes rather like a showerhead; when the solution is forced through it, long strands of fiber come out. The fibers are then immersed in another solution of amine oxide, diluted this time, which sets the fiber strands. Then they are washed with de-mineralized water.
Drying and finishing The Lyocell fiber next passes to a drying area, where the water is evaporated from it. The strands then pass to a finishing area, where a lubricant, which may be a soap or silicone or other agent depending on the future use of the fiber, is applied. This step is basically a detangler, making the following steps of carding and spinning into yarn easier.
Final steps The dried, finished fibers are at this stage in a form called tow, a large untwisted bundle of continuous lengths of filament. The bundles of tow are taken to a crimper, a machine which compresses the fiber, giving it texture and bulk. The crimped fiber is carded by mechanical carders, which perform an action like combing, to separate and order the strands. The carded strands are cut and baled for shipment to a fabric mill. The entire manufacturing process, from unrolling the raw cellulose to baling the fiber, takes about two hours. After this, the Lyocell may be processed in many ways. It may be spun with another fiber, such as cotton or wool. The resulting yarn can be woven or knitted like any other fabric, and given a variety of finishes, from soft and suede-like to silky.
Recovery of the solvent The amine oxide used to dissolve the cellulose and set the fiber after spinning is recovered and re-used: the dilute solution is evaporated to remove the water, leaving amine oxide which is used for dissolving the next batch of cellulose. 98% of the amine oxide is typically recovered.
Lyocell fiber
Lyocell is a regenerated cellulose fiber made from dissolving pulp (bleached wood pulp). It was first manufactured in 1987 by Courtaulds Fibres UK at their pilot plant S25. As of 2010[update] it is manufactured by Lenzing AG of Lenzing, Austria, under the brand name "Lyocell by Lenzing", and under the brand name Tencel by the Tencel group, now owned by Lenzing AG.
The US Federal Trade Commission defines Lyocell as "a cellulose fabric that is obtained by an organic solvent spinning process". It classifies the fibre as a sub-category of rayon.
The fiber is used to make textiles for clothing and other purposes.
The US Federal Trade Commission defines Lyocell as "a cellulose fabric that is obtained by an organic solvent spinning process". It classifies the fibre as a sub-category of rayon.
The fiber is used to make textiles for clothing and other purposes.
Modal spandex fiber
Modal is a cellulose fiber made by spinning reconstituted cellulose from beech trees. It is about 50% more hygroscopic (water-absorbent) per unit volume than cotton. It takes dye just like cotton, and is color-fast when washed in warm water. Modal is essentially a variety of rayon.
Textiles made from Modal are resistant to shrinkage and fading. They are smooth and soft, more so than mercerized cotton, to the point where mineral deposits from hard water do not stick to the fabric surface. Modal fabrics should be washed at lower temperatures and ironed after washing.
Lenzing Modal is a registered trademark of Lenzing AG, an Austrian company specializing in textiles and fibers, particularly natural fibers made from cellulose. Modal has been used alone or with other fibers in household linens such as towels, bathrobes, and bedsheets, and the fabric has increased in popularity in the early twentyfirst century.
Many textile companies use Modal mixed with other fibers such as spandex. Modal has gained ground in India; Indian textile companies were expected to produce around 4000 tons in 2005
Textiles made from Modal are resistant to shrinkage and fading. They are smooth and soft, more so than mercerized cotton, to the point where mineral deposits from hard water do not stick to the fabric surface. Modal fabrics should be washed at lower temperatures and ironed after washing.
Lenzing Modal is a registered trademark of Lenzing AG, an Austrian company specializing in textiles and fibers, particularly natural fibers made from cellulose. Modal has been used alone or with other fibers in household linens such as towels, bathrobes, and bedsheets, and the fabric has increased in popularity in the early twentyfirst century.
Many textile companies use Modal mixed with other fibers such as spandex. Modal has gained ground in India; Indian textile companies were expected to produce around 4000 tons in 2005
Wednesday, August 4, 2010
Clariant Textile Chemicals
Confidence in textiles – this has been the motto of the independent test institutes of the International Oeko-Tex Association since 1992, with its tests for harmful substances according to the Oeko-Tex Standard 100 for textile products. The Oeko-Tex Standard 100 is a globally uniform testing and certification system for textiles (yarn, fibers, fabrics). For companies in the textile and clothing industry, the Oeko-Tex criteria catalog provides a uniform, scientifically founded evaluation standard for the human ecological safety of textiles.
Additionally, the well-known Oeko-Tex label informs interested end users of the additional benefits of tested safety for skin-friendly clothing and other textiles.
Additionally, the well-known Oeko-Tex label informs interested end users of the additional benefits of tested safety for skin-friendly clothing and other textiles.
Clariant
Novartis International AG is a multinational pharmaceutical company based in Basel, Switzerland, ranking number three in sales, which accounted 36.173 billon in 2008. It is currently the 6th largest Pharmaceutical company in terms of revenue ($41.5 billion in 2009) with a profit margin of about 20%, which is the same as its industry competitors. Their profits were down by 31% from 2007 levels.[4] Novartis manufactures drugs such as clozapine (Clozaril), diclofenac (Voltaren), carbamazepine (Tegretol), valsartan (Diovan), imatinib mesylate (Gleevec / Glivec), ciclosporin (Neoral / Sandimmun), letrozole (Femara), methylphenidate (Ritalin), terbinafine (Lamisil), and others. Novartis owns Sandoz, a large manufacturer of generic drugs. The company formerly owned the Gerber Products Company, a major infant and baby products producer, but sold it to Nestlé on 1 September 2007.
Novartis is a full member of the European Federation of Pharmaceutical Industries and Associations (EFPIA) and of the International Federation of Pharmaceutical Manufacturers & Associations (IFPMA)
Novartis is a full member of the European Federation of Pharmaceutical Industries and Associations (EFPIA) and of the International Federation of Pharmaceutical Manufacturers & Associations (IFPMA)
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