Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, bacteria, and liquid water makes it useful for food packaging. Cellophane is highly permeable to water vapour, but may be coated with nitrocellulose lacquer to prevent this.
Cellophane is also used in transparent pressure-sensitive tape, tubing, and many other similar applications.
Cellophane is compostable and biodegradable, and can be obtained from biomaterials. [1] The original production process uses carbon disulfide (CS2), which has been found to be highly toxic to workers. [2] The newer lyocell process can be used to produce cellulose film without involving carbon disulfide. [3]
"Cellophane" is a generic term in some countries, [4] while in other countries it is a registered trademark.
Cellulose from wood, cotton, hemp, or other sources is dissolved in alkali and carbon disulfide to make a solution called viscose, which is then extruded through a slit into a bath of dilute sulfuric acid and sodium sulfate to reconvert the viscose into cellulose. The film is then passed through several more baths, one to remove sulfur, one to bleach the film, and one to add softening materials such as glycerin to prevent the film from becoming brittle.
A similar process, using a hole (a spinneret) instead of a slit, is used to make a fibre called rayon. Chemically, cellophane, rayon, and cellulose are polymers of glucose; they differ structurally rather than chemically.
Cellophane was invented by Swiss chemist Jacques E. Brandenberger while employed by Blanchisserie et Teinturerie de Thaon. [6] In 1900, inspired by seeing wine spill on a restaurant's tablecloth, he decided to create a cloth that could repel liquids rather than absorb them. His first step was to spray a waterproof coating onto fabric, and he opted to try viscose. The resultant coated fabric was far too stiff, but the diaphanous film coating could be separated from the backing cloth easily and in one undamaged piece. Seeing the possibilities of this new material on its own, Brandenberger soon abandoned his original idea.
It took ten years for Brandenberger to perfect his film. His chief improvement over earlier work with such films was adding glycerin to soften the material. By 1912 he had constructed a machine to manufacture the film, which he had named Cellophane, from the words cellulose and diaphane ("transparent"). Cellophane was patented that year. [7] The following year, the company Comptoir des Textiles Artificiels (CTA) bought the Thaon firm's interest in Cellophane and established Brandenberger in a new company, La Cellophane SA. [8]
Whitman's candy company initiated use of cellophane for candy wrapping in the United States in 1912 for their Whitman's Sampler. They remained the largest user of imported cellophane from France until nearly 1924, when DuPont built the first cellophane manufacturing plant in the US. Cellophane saw limited sales in the US at first since while it was waterproof, it was not moisture proof—it held or repelled water but was permeable to water vapor. This meant that it was unsuited to packaging products that required moisture proofing. DuPont hired chemist William Hale Charch (1898–1958), who spent three years developing a nitrocellulose lacquer that, when applied to Cellophane, made it moisture proof. [9] Following the introduction of moisture-proof Cellophane in 1927, the material's sales tripled between 1928 and 1930, and in 1938, Cellophane accounted for 10% of DuPont's sales and 25% of its profits. [8]
Cellophane played a crucial role in developing the self-service retailing of fresh meat. [10] Cellophane visibility helped customers know quality of meat before buying. Cellophane also worked to consumers' disadvantage when manufacturers learned to manipulate the appearance of a product by controlling oxygen and moisture levels to prevent discolouration of food. [10] It was considered such a useful invention that cellophane was listed alongside other modern marvels in the 1934 song "You're the Top" (from Anything Goes ). [11] [12] [13]
The British textile company Courtaulds' viscose technology had allowed it to diversify in 1930 into viscose film, which it named "Viscacelle". However, competition with Cellophane was an obstacle to its sales, and in 1935 it founded British Cellophane Limited (BCL) in conjunction with the Cellophane Company and its French parent company CTA. [14] A major production facility was constructed at Bridgwater, Somerset, England, from 1935 to 1937, employing 3,000 workers. BCL subsequently constructed plants in Cornwall, Ontario (BCL Canada), as an adjunct to the existing Courtaulds viscose rayon plant there (from which it bought the viscose solution), and in 1957 at Barrow-in-Furness, Cumbria. The latter two plants were closed in the 1990s.
Cellulose film has been manufactured continuously since the mid-1930s and is still used today. As well as packaging a variety of food items, there are also industrial applications, such as a base for such self-adhesive tapes as Sellotape and Scotch Tape, a semi-permeable membrane in a certain type of battery,[ which? ] as dialysis tubing (Visking tubing), and as a release agent in the manufacture of fibreglass and rubber products. Cellophane is the most popular material for manufacturing cigar packaging; its permeability to water vapor makes cellophane a good product for this application as cigars must be allowed to "breathe" while wrapped and in storage.
Cellophane sales have dwindled since the 1960s, due to alternative packaging options. The polluting effects of carbon disulfide and other by-products of the process used to make viscose may have also contributed[ citation needed ] to its falling behind lower cost petrochemical-based films such as biaxially-oriented polyethylene terephthalate (BoPET) and biaxially oriented polypropylene (BOPP) in the 1980s and 1990s. However, as of 2017, it has made something of a resurgence in recent times due to its being biosourced, compostable, and biodegradable. Its sustainability record is clouded by its energy-intensive manufacturing process and the potential negative impact of some of the chemicals used, but significant progress in recent years has been made by leading manufacturers in reducing their environmental footprint. [1]
When placed between two plane polarizing filters, cellophane produces prismatic colours due to its birefringent nature. Artists have used this effect to create stained glass-like creations that are kinetic and interactive.
Cellophane is biodegradable, but highly toxic carbon disulfide is used in most cellophane production. Viscose factories vary widely in the amount of CS2 they expose their workers to, and most give no information about their quantitative safety limits or how well they keep to them. [2] [15]
In the UK and in many other countries, "Cellophane" is a registered trademark and the property of Futamura Chemical UK Ltd, based in Wigton, Cumbria, United Kingdom. [16] [17] In the USA and some other countries "cellophane" has become genericized, and is often used informally to refer to a wide variety of plastic film products, even those not made of cellulose, such as PVC-based plastic wrap.
Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, classified according to the monomers used and the structure of the biopolymer formed: polynucleotides, polypeptides, and polysaccharides. The Polynucleotides, RNA and DNA, are long polymers of nucleotides. Polypeptides include proteins and shorter polymers of amino acids; some major examples include collagen, actin, and fibrin. Polysaccharides are linear or branched chains of sugar carbohydrates; examples include starch, cellulose, and alginate. Other examples of biopolymers include natural rubbers, suberin and lignin, cutin and cutan, melanin, and polyhydroxyalkanoates (PHAs).
Cellulose is an organic compound with the formula (C
6H
10O
5)
n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fibre is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%.
Rayon, also called viscose and commercialised in some countries as sabra silk or cactus silk, is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. Many types and grades of viscose fibers and films exist. Some imitate the feel and texture of natural fibers such as silk, wool, cotton, and linen. The types that resemble silk are often called artificial silk. It can be woven or knit to make textiles for clothing and other purposes.
Carbon disulfide is an inorganic compound with the chemical formula CS2 and structure S=C=S. It is also considered as the anhydride of thiocarbonic acid. It is a colorless, flammable, neurotoxic liquid that is used as a building block in organic synthesis. Pure carbon disulfide has a pleasant, ether- or chloroform-like odor, but commercial samples are usually yellowish and are typically contaminated with foul-smelling impurities.
Synthetic fibers or synthetic fibres are fibers made by humans through chemical synthesis, as opposed to natural fibers that are directly derived from living organisms, such as plants or fur from animals. They are the result of extensive research by scientists to replicate naturally occurring animal and plant fibers. In general, synthetic fibers are created by extruding fiber-forming materials through spinnerets, forming a fiber. These are called synthetic or artificial fibers. The word polymer comes from a Greek prefix "poly" which means "many" and suffix "mer" which means "single units"..
In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and as a frame material for eyeglasses; it is also used as a synthetic fiber in the manufacture of cigarette filters and playing cards. In photographic film, cellulose acetate film replaced nitrate film in the 1950s, being far less flammable and cheaper to produce.
Lyocell is a semi-synthetic fiber used to make textiles for clothing and other purposes. It is a form of regenerated cellulose made by dissolving pulp and dry jet-wet spinning. Unlike rayon made by the more common viscose processes, Lyocell production does not use carbon disulfide, which is toxic to workers and the environment. Lyocell was originally trademarked as Tencel in 1982.
Polymer chemistry is a sub-discipline of chemistry that focuses on the structures of chemicals, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules. However, polymer chemistry is typically related to synthetic and organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, such as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.
Dialysis tubing, also known as Visking tubing, is an artificial semi-permeable membrane tubing used in separation techniques, that facilitates the flow of tiny molecules in solution based on differential diffusion. In the context of life science research, dialysis tubing is typically used in the sample clean-up and processing of proteins and DNA samples or complex biological samples such as blood or serums. Dialysis tubing is also frequently used as a teaching aid to demonstrate the principles of diffusion, osmosis, Brownian motion and the movement of molecules across a restrictive membrane. For the principles and usage of dialysis in a research setting, see Dialysis (biochemistry).
A xanthate is a salt or ester of a xanthic acid. The formula of the salt of xanthic acid is [R−O−CS2]−M+. Xanthate also refers to the anion [R−O−CS2]−. The formula of a xanthic acid is R−O−C(=S)−S−H, such as ethyl xanthic acid, while the formula of an ester of a xanthic acid is R−O−C(=S)−S−R', where R and R' are organyl groups. The salts of xanthates are also called O-organyl dithioates. The esters of xanthic acid are also called O,S-diorganyl esters of dithiocarbonic acid. The name xanthate is derived from Ancient Greek ξανθός (xanthos) meaning 'yellowish' or 'golden', and indeed most xanthate salts are yellow. They were discovered and named in 1823 by Danish chemist William Christopher Zeise. These organosulfur compounds are important in two areas: the production of cellophane and related polymers from cellulose and for extraction of certain sulphide bearing ores. They are also versatile intermediates in organic synthesis.
Bioplastics are plastic materials produced from renewable biomass sources. Historically, bioplastics made from natural materials like shellac or cellulose had been the first plastics. Since the end of the 19th century they have been increasingly superseded by fossil-fuel plastics derived from petroleum or natural gas. Today, in the context of bioeconomy and circular economy, bioplastics are gaining interest again. Conventional petro-based polymers are increasingly blended with bioplastics to manufacture "bio-attributed" or "mass-balanced" plastic products - so the difference between bio- and other plastics might be difficult to define.
British Cellophane Ltd (BCL) was a joint venture company formed in 1935 between La Cellophane SA and Courtaulds, when they began building a major factory for producing Cellophane in Bridgwater, Somerset, England.
Courtaulds was a United Kingdom-based manufacturer of fabric, clothing, artificial fibres, and chemicals. It was established in 1794 and became the world's leading man-made fibre production company before being broken up in 1990 into Courtaulds plc and Courtaulds Textiles Ltd.
Biodegradable plastics are plastics that can be decomposed by the action of living organisms, usually microbes, into water, carbon dioxide, and biomass. Biodegradable plastics are commonly produced with renewable raw materials, micro-organisms, petrochemicals, or combinations of all three.
Bamboo textile is any cloth, yarn or clothing made from bamboo fibres. While bamboo was historically used only for structural elements, such as bustles and the ribs of corsets, in recent years various technologies have been developed that allow bamboo fibre to be used for a wide range of textile and fashion applications.
Dissolving pulp, also called dissolving cellulose, is bleached wood pulp or cotton linters that has a high cellulose content. It has special properties including a high level of brightness and uniform molecular-weight distribution. This pulp is manufactured for uses that require a high chemical purity, and particularly low hemicellulose content, since the chemically similar hemicellulose can interfere with subsequent processes. Dissolving pulp is so named because it is not made into paper, but dissolved either in a solvent or by derivatization into a homogeneous solution, which makes it completely chemically accessible and removes any remaining fibrous structure. Once dissolved, it can be spun into textile fibers, or chemically reacted to produce derivatized celluloses, such cellulose triacetate, a plastic-like material formed into fibers or films, or cellulose ethers such as methyl cellulose, used as a thickener.
Cellulose fibers are fibers made with ethers or esters of cellulose, which can be obtained from the bark, wood or leaves of plants, or from other plant-based material. In addition to cellulose, the fibers may also contain hemicellulose and lignin, with different percentages of these components altering the mechanical properties of the fibers.
The U.S. Flammable Fabrics Act is an act that was passed in 1953 to regulate the manufacture of highly flammable clothing. It was enacted after years of rayon viscose fabrics being proven to be the primary cause of quick starting, high temperature fires as well as having the secondary effect of causing illnesses in factory workers. Viscose is the key word when describing the chemical dangers of rayon fabrics, because a chemical named carbon disulfide is used to convert cellulose into a viscose fabric capable of being threaded together for clothing. This is an important distinction to make for the sake of clarity as cellulose fabrics are still commonly advertised as "green" in the sense that the fabric is derived from the cellulose in plants, but the introduction of carbon disulfide in the manufacturing process creates a reaction that is remarkably toxic to the workers who are developing and working with the fabric. There was also a series of tragic deaths in the 1940s caused by the highly flammable nature of the fabric involving children who were wearing long rayon pile cowboy chaps or brushed rayon sweaters. The Federal Trade Commission was initially placed as the enforcement authority but this responsibility was later transferred over to the Consumer Product Safety Commission in 1967 when the act was amended to include interior furnishings, paper, plastic, foam, and other materials used in wearing apparel and interior furnishings. A provision of the act makes willful violation a felony with maximum penalties of a $10,000 fine and 3 years in prison, which reflects how seriously the dangers of flammable fabrics were being taken. The Consumer Product Safety Commission was given the authority, under the U.S. Flammable Fabrics Act, to issue mandatory flammability standards. Flammability standards for clothing textiles, vinyl plastic film in clothing, carpets, rugs, children's sleepwear, mattresses, and mattress pads have all been established.
Green textiles are fabrics or fibres produced to replace environmentally harmful textiles and minimise the ecological impact. Green textiles are part of the sustainable fashion and eco-friendly trends, providing alternatives to the otherwise pollution-heavy products of conventional textile industry, which is deemed the most ecologically damaging industry.
Red Scar Works was built in 1939 by Courtaulds and produced continuous filament viscose rayon. It was located in Ribbleton, Preston, off Longridge Road. The closure of the works was announced in November 1979 and the issue raised in the UK Parliament House of Commons by the constituency MP. At the time of closure, approximately 2,600 people were employed there, but there were approximately 4,000 at its peak. It was at one time the largest rayon producing site in Britain. Two main products were manufactured: one being tyre yarn made by a process known as CSPT, trademarked Tenasco, in two principle deniers; the other being a general-purpose textile yarn called Bright. A range of deniers of this were produced; pigmented variants in a wide range of colours were trademarked Duracol. At the time of closure, one reason given by management for the closure was the rising popularity of steel belt radial tyres, thus reducing demand for viscose tyre yarn.
Cellophane is biosourced, compostable, and biodegradable.
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