Cellophane, manufacture

Use Viscose rayon, cellophane, manufacture of carbon tetrachloride and flotation agents, solvent. 

Synthetic glycerin, produced by the chlorination of allyl alcohol to form dichloro-hydrin followed by hydrolysis, is the raw material in the manufacture of allyl resins and the production of nitroglycerine and other explosives. It is also used as a humectant in tobacco processing and as a plasticizer in cellophane manufacturing. 

Carbon disulfide is used in viscose rayon and cellophane manufacture and in the production of carbontetrachloride. In the generally preferred process, vaporized sulfur is reacted with methane according to the reactions... 

Plastics and Other Synthetic Products. Sulfur is used in the production of a wide range of synthetics, including cellulose acetate, cellophane, rayon, viscose products, fibers, and textiles. These uses may account for 2% of sulfur demand in developed countries. Sulfur intermediates for these manufacturing processes are equally divided between carbon disulfide and sulfuric acid. 

Use of carbon disulfide for manufacture of cellophane [9005-81-6] has dropped dramatically because of competition from plastic films, and just one cellophane producer, Flexel, Inc., remains in the United States. 

World production in 1991 was about 1 million tonnes the principal industrial uses being in the manufacture of viscose rayon (35-50%), cellophane films (15%) (see below), and CCI4 (15 30%) depending on country. Indeed the CCI4 application dropped to zero in USA in 1991 because of environmental concerns (p. 304). 

There are many difficulties encountered in the manufacture and distribution of these iced sweet rolls, which are hermetically sealed in cellophane. During hot and humid weather the icing melts and disappears and may stick to the wrapper. The icing may also crack and peel and develop a dull appearance. 

The substances generally used as osmotic membranes include collodion (nitrocellulose of 11-13.5 per cent nitrogen) regenerated cellulose, obtained by denitration of collodion gel cellophane that has never permitted to dry after manufacture bacterial cellulose, obtained by the action of certain strains of bacteria rubber, poly (vinyl alcohol) polyurethances poly (vinyl butyral) and polychlorotrifluoroethylene. At present gel cellophane is most widely used. 

One of the earlier methods was to treat cellulose with sodium hydroxide and carbon disulfide to obtain xanthate esters which could be dispersed in water and cast into sheets or spun into fibers. Subsequent treatment with acid decomposed the xanthates and gave regenerated cellulose, either in fiber or film form. The fibers were called viscose rayon and the films were named cellophane. Cellophane is still used as a wrapping film and some of it is still manufactured by the xanthate process. By treatment with nitric acid, cellulose was converted to a trinitric acid ester, which could be cast into units which were satisfactory for making gun cotton for a smokeless powder for either artillery shells or shotgun ammunition. It was quite insoluble but it could be converted to a jelly-like mass, which could be shaped into a desired form for ammunition use. Under milder conditions, a lower nitrate... 

Cellophane is frequently used for dialysis and it has a pore size of approximately 4—8 gm, which makes it impermeable to molecules with a relative molecular mass in excess of about 10 000. The development of a variety of membrane materials in which the pore size is much more rigorously controlled, has led to wider applications of ultrafiltration (Table 3.11). Various cellulose and polycarbonate membranes are available with pore sizes down to 5 nm which are capable of excluding molecules with a relative molecular mass of about 50. The internal structure of such membranes, as well as the pore size, determines their exclusion range and as a result precise specifications of membranes vary from one manufacturer to another. 

A separator is a porous membrane placed between electrodes of opposite polarity, permeable to ionic flow but preventing electric contact of the electrodes. A variety of separators have been used in batteries over the years. Starting with cedar shingles and sausage casing, separators have been manufactured from cellulosic papers and cellophane to nonwoven fabrics, foams, ion exchange membranes, and microporous flat sheet membranes made from polymeric materials. As batteries have become more sophisticated, separator function has also become more demanding and complex. 

Uses Manufacture of viscose rayon, cellophane, flotation agents, ammonium salts, carbon tetrachloride, carbanilide, paints, enamels, paint removers, varnishes, tallow, textiles, rocket fuel, soil disinfectants, electronic vacuum tubes, herbicides grain fumigants solvent for fats, resins, phosphorus, sulfur, bromine, iodine, and rubber petroleum and coal tar refining solvent and eluant for organics adsorbed on charcoal for air analysis. 

Uses. Manufacture of rayon viscose fibers and cellophane film solvent for lipids, sulfur, rubber, phosphorus, oils, resins, and waxes insecticide... 

PE did not receive much commercial use until after the war when it was used in the manufacture of film and molded objects. PE film displaced cellophane in many applications being used for packaging produce, textiles, and frozen and perishable foods. This PE was branched and had a relatively low softening temperature, below 100°C, preventing its use for materials where boiling water was needed for sterilization. 

Carbon disulfide is used in the manufacture of rayon, cellophane, electronic vacuum tubes, and xanthogenates. It is used to make carbon tetrachloride. It also is used as an industrial solvent and as an analytical solvent. Because of its low response to GC-FID, it is used widely in air analysis of organic compounds. 

The Food and Dmg Administration (1999) permits the use of di(2-ethylhexyl) phthalate in the United States as a component of adhesives used in food packaging, as a plasticizer in resinous and polymeric coatings used in food packaging, as a component of defoaming agents used in the manufacture of paper and paperboard used in food packaging, as a flow promoter in food contact surfaces not to exceed 3 wt% based on monomers, as a component of cellophane where total phthalates do... 

According to the 1981-83 National Occupational Exposure Survey, as many as 15 600 workers in the United States were potentially exposed to di(2-ethylhexyl) adipate (NOES, 1999). Occupational exposure may occur through inhalation, mainly as an aerosol, during its manufacture and its use, particularly as a plasticizer of PVC films and in other materials used in food packaging such as adhesives, cellophane and hydroxy ethyl cellulose films. Exposure may also occur during the manufacture of rubber products, nonferrous wire, cosmetics, lubricants and hydraulic fluids (Opresko, 1984). No measurements of di(2-ethylhexyl) adipate exposure in manufacturing and processing industries are available. 

Cellulosic raw materials. Linters or wood pulp cellulose are in use as raw material for manufacturing lacquer nitrocellulose. It is essential to use very well purified and bleached raw material. Wood cellulose should contain mainly a-cellulose. The admissible pentosan content is limited to traces only, because these compounds are a source of products insoluble in organic solvents. Cellophane can also be utilized for nitration. 

Carbon disulfide has been u imtjur chemical I m main years, Two-thirds of ils use was in viscose ruyon und cellophane production. Most of the real was used to produce carbon tetrachloride. Neither of these outlets appear to provide much future growth for carbon disulfide. The major manufacturing route is to react methane and sulfur vapor at OOtTC over u catalyst... 

Methane (CH4) reacts with hydrogen sulfide to yield H2 and carbon disulfide, a solvent used in manufacturing rayon and cellophane ... 

The large-scale uses of carbon disulfide center mainly about its properties as a solvent. Many fats, oils, waxes, and resins are abundantly soluble in this liquid. Despite the disadvantages attendant upon its volatility, flammability, and toxicity, carbon disulfide is used extensively as a solvent and in processes for the manufacture of rubber products, lacquers, varnishes, cellophane, and so forth. Because of its toxicity, this compound is used to some extent as an insecticide and as a poison for rodents. 

Carbon disulfide (CS2) is one of the most significant sulfur compounds because of its widespread use and toxicity. This compound has two sulfur atoms, each separately bonded to a carbon atom. This compound is a volatile, colorless liquid (mp, -111°C bp, 46°C). Unlike most organosulfur compounds, it is virtually free of odor. Although its uses are declining, it has numerous applications in chemical synthesis, as a solvent to break down cellulose in viscose rayon manufacture, and in the manufacture of cellophane. It has also been used as an insecticide and fumigant. 

Cellophane film Is prepared from regenerated cellulose and Is similar to rayon fiber In that It has a lower molecular weight than cotton and contains a small amount of hemlcellulose, as does linen. Cellophane film, therefore, although not a duplicate of any natural fiber, Is similar enough In chemical structure and morphology to make It useful as a model system. Moreover, Its transparency and the precision of Its manufacture make It quite useful for this type of study. 

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