Plastic wrap

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A roll of plastic wrap Pvc-Film.jpg
A roll of plastic wrap

Plastic wrap, cling film, Saran wrap, cling wrap, Glad wrap or food wrap is a thin plastic film typically used for sealing food items in containers to keep them fresh over a longer period of time. Plastic wrap, typically sold on rolls in boxes with a cutting edge, clings to many smooth surfaces and can thus remain tight over the opening of a container without adhesive. Common plastic wrap is roughly 0.0005 inches (12.7 μm) thick. [1] [2] The trend has been to produce thinner plastic wrap, particularly for household use (where very little stretch is needed), so now the majority of brands on shelves around the world are 8, 9 or 10 μm thick.

Contents

Materials used

Plastic wrap was initially[ when? ] created from polyvinyl chloride (PVC), which remains the most common component globally. PVC has an acceptably-low permeability to water vapor and oxygen, [3] helping to preserve the freshness of food. There are concerns about the transfer of plasticizers from PVC into food.[ citation needed ] Pliofilm was made of various kinds of rubber chloride. Used in the middle of the 20th century, it could be heat-sealed. [4]

A common, cheaper alternative to PVC is low-density polyethylene (LDPE). It is less adhesive than PVC, but this can be remedied by adding linear low-density polyethylene (LLDPE), which also increases the film's tensile strength. [5]

In the US and Japan, plastic wrap is sometimes produced using polyvinylidene chloride (PVdC), though some brands, such as Saran wrap, have switched to other formulations due to environmental concerns. [6]

Food use

Purpose

Bread wrapped in plastic wrap Daujenu namine duona.JPG
Bread wrapped in plastic wrap

The most important role plastic wrap plays in food packaging is protection and preservation. Plastic wrap can prevent food from perishing, extend its shelf-life, and maintain the quality of food. Plastic wrap generally provides protection for food from three aspects: chemical (gases, moisture, and light), biological (microorganisms, insects and animals), and physical (mechanical damage). In addition to food protection and preservation, plastic wrap can also reduce food waste, tag food information, ease the distribution processes, and increase product visibility and microwavability. [7]

In the 1970s, Snappies cling-film was advertised in the UK by Katie Boyle. [8]

Health concern

Plastic materials are widely used in the food industry due to their low price and convenience; however, there has been an increased health concern because of the possibility of releasing undesirable chemicals from plastic materials into food products. Plastic packages are made of various materials such as polyethylene, low-density polyethylene, etc. Additives, including lubricants, plasticizers, UV-absorbers, colorants, and antioxidants, are added into plastic materials in order to improve the quality and properties of the plastics. Besides, plastic materials are often coated and printed in the final processes, in which inks and varnishes are used. Although the barrier properties of the plastic packages provide protection of foods from external contaminations, the additives and coating materials in the plastic packages are able to penetrate into foods and cause health-related issues. [9]

"It is true that substances used to make plastics can leach into food," says Edward Machuga, Ph.D., a consumer safety officer in the FDA's Center for Food Safety and Applied Nutrition. “But as part of the approval process, the FDA considers the amount of a substance expected to migrate into food and the toxicological concerns about the particular chemical.” A couple of cases have caught media attention in recent years. One case is in regard to diethylhexyl adipate (DEHA). DEHA is a plasticizer, a substance added to some plastics in order to make them flexible. There are public concerns about DEHA exposure while consuming food with plastic wraps. There are potentials of exposure to DEHA; however, the levels of the exposure are much lower than the no toxic effect levels in animal studies. Another case is in regard to the dioxins, labeled as "likely human carcinogen" by the Environmental Protection Agency. The public has been misled by the claims that plastics contain dioxins [ citation needed ], while Machuga stated that no evidence that shows plastic containers or films contain dioxins was seen by the FDA [ citation needed ]. According to writing in FDA Consumer Magazine as of November 2002, when used properly the use of plastic wrap in food preparation does not pose danger to human health. [10]

Environmental concerns

The accumulation of plastic debris on the Earth threatens both wildlife and the environment. Plastic debris might choke or trap wildlife, and it could also penetrate toxic compounds into ecosystems. This land-originated problem has become a problem in ocean ecosystem as well since streams and rivers which are close to the land have carried the plastic debris into the coast, and currents transfer it to everywhere in the ocean. Plastic debris is a potential danger to all forms of aquatic life. Some marine species, like sea turtles, take plastic as prey items by mistake. Besides, some species might even pick up plastics and feed their offspring, which cause huge problems on growth and even cause mortality. Toxic compounds in plastics can disrupt hormone regulation in the cells of organisms, which can lead to alteration of animals’ mating behavior, reproductive ability, and even cause the development of tumors. Plastic debris could be a big threat to lives in the ocean. [11]

A study shows that using recycled plastic materials can reduce the environmental impacts significantly as a result of minimizing exploration, mining and transportation of natural gas and oil. One of the possible ways to increase the recycling rate is adding fibrous reinforcement into plastics. The environmental impact has been assessed using the life cycle assessment method. The results showed that plastics with fibrous reinforcement added can sharply reduce resource usage and global warming in civil applications. [12]

Medical use

See also

Related Research Articles

<span class="mw-page-title-main">Polyvinyl chloride</span> Common synthetic polymer

Polyvinyl chloride (alternatively: poly(vinyl chloride), colloquial: polyvinyl, or simply vinyl; abbreviated: PVC) is the world's third-most widely produced synthetic polymer of plastic (after polyethylene and polypropylene). About 40 million tons of PVC are produced each year.

<span class="mw-page-title-main">Polyethylene</span> Most common thermoplastic polymer

Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, etc.). As of 2017, over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market.

<span class="mw-page-title-main">Thermoplastic</span> Plastic that softens with heat and hardens on cooling

A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.

<span class="mw-page-title-main">PET bottle recycling</span> Recycling of bottles made of polyethylene terephthalate

Although PET is used in several applications,, as of 2022 only bottles are collected at a substantial scale. The main motivations have been either cost reduction or recycle content of retail goods. An increasing amount is recycled back into bottles, the rest goes into fibres, film, thermoformed packaging and strapping. After sorting, cleaning and grinding, 'bottle flake' is obtained, which is then processed by either:

<span class="mw-page-title-main">Shrink wrap</span> Polymer used to bundle boxes on a pallet for transport

Shrink wrap, also shrink film, is a material made up of polymer plastic film. When heat is applied, it shrinks tightly over whatever it is covering. Heat can be applied with a handheld heat gun, or the product and film can pass through a heat tunnel on a conveyor.

<span class="mw-page-title-main">Label</span> Material affixed to a container or article with printed information

A label is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed directly on a container or article can also be considered labelling.

<span class="mw-page-title-main">Plastic bag</span> Type of container made of thin, flexible, plastic film, nonwoven fabric, or plastic textile

A plastic bag, poly bag, or pouch is a type of container made of thin, flexible, plastic film, nonwoven fabric, or plastic textile. Plastic bags are used for containing and transporting goods such as foods, produce, powders, ice, magazines, chemicals, and waste. It is a common form of packaging.

<span class="mw-page-title-main">High-density polyethylene</span> Class of polyethylenes

High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code.

<span class="mw-page-title-main">Plastic recycling</span> Processes which convert waste plastic into new items

Plastic recycling is the processing of plastic waste into other products. Recycling can reduce dependence on landfill, conserve resources and protect the environment from plastic pollution and greenhouse gas emissions. Recycling rates lag those of other recoverable materials, such as aluminium, glass and paper. Through 2015, the world produced some 6.3 billion tonnes of plastic waste, only 9% of which has been recycled, and only ~1% has been recycled more than once. Additionally, 12% was incinerated and the remaining 79% sent to landfill or to the environment including the ocean.

<span class="mw-page-title-main">Low-density polyethylene</span> Chemical compound

Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Dr John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its manufacture employs the same method today. The EPA estimates 5.7% of LDPE is recycled in the United States. Despite competition from more modern polymers, LDPE continues to be an important plastic grade. In 2013 the worldwide LDPE market reached a volume of about US$33 billion.

<span class="mw-page-title-main">Linear low-density polyethylene</span> Polymer

Linear low-density polyethylene (LLDPE) is a substantially linear polymer (polyethylene), with significant numbers of short branches, commonly made by copolymerization of ethylene with longer-chain olefins. Linear low-density polyethylene differs structurally from conventional low-density polyethylene (LDPE) because of the absence of long chain branching. The linearity of LLDPE results from the different manufacturing processes of LLDPE and LDPE. In general, LLDPE is produced at lower temperatures and pressures by copolymerization of ethylene and such higher alpha-olefins as butene, hexene, or octene. The copolymerization process produces an LLDPE polymer that has a narrower molecular weight distribution than conventional LDPE and in combination with the linear structure, significantly different rheological properties.

Saran is a trade name used by S.C. Johnson & Son, Inc. for a polyethylene food wrap. The Saran trade name was first owned by Dow Chemical for polyvinylidene chloride (PVDC), along with other monomers. The formulation was changed to the less effective polyethylene in 2004 due to the chlorine content of PVDC.

Polyethylene or polythene film biodegrades naturally, albeit over a long period of time. Methods are available to make it more degradable under certain conditions of sunlight, moisture, oxygen, and composting and enhancement of biodegradation by reducing the hydrophobic polymer and increasing hydrophilic properties.

Polyvinylidene chloride, or polyvinylidene dichloride (PVDC), is a homopolymer of vinylidene chloride.

<span class="mw-page-title-main">Plastic bottle</span> Narrow-necked container

A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo, milk, and ink. The size ranges from very small bottles to large carboys. Consumer blow molded containers often have integral handles or are shaped to facilitate grasping.

<span class="mw-page-title-main">Stretch wrap</span> Packaging material

Stretch wrap or stretch film, sometimes known as pallet wrap, is a highly stretchable plastic film that is wrapped around items. The elastic recovery keeps the items tightly bound. In contrast, shrink wrap is applied loosely around an item and shrinks tightly with heat. While it is similar to plastic food wrap, it is not usually made of material rated as safe for food contact.

<span class="mw-page-title-main">Commodity plastics</span> Inexpensive plastics with weak mechanical properties

Commodity plastics or commodity polymers are plastics produced in high volumes for applications where exceptional material properties are not needed. In contrast to engineering plastics, commodity plastics tend to be inexpensive to produce and exhibit relatively weak mechanical properties. Some examples of commodity plastics are polyethylene, polypropylene, polystyrene, polyvinyl chloride, and poly(methyl methacrylate) .Globally, the most widely used thermoplastics include both polypropylene and polyethylene. Products made from commodity plastics include disposable plates, disposable cups, photographic and magnetic tape, clothing, reusable bags, medical trays, and seeding trays.

Biopolyethylene is polyethylene made out of ethanol, which becomes ethylene after a dehydration process. It can be made from various feedstocks including sugar cane, sugar beet, and wheat grain.

<span class="mw-page-title-main">Disposable food packaging</span>

Disposable food packaging comprises disposable products often found in fast-food restaurants, take-out restaurants and catering establishments. Typical products are foam food containers, plates, bowls, cups, utensils, doilies and tray papers. These products can be made from a number of materials including plastics, paper, bioresins, wood and bamboo.

<span class="mw-page-title-main">Plastic</span> Material of a wide range of synthetic or semi-synthetic organic solids

Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives.

References

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