BoPET is a polyester

Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...

 film made from stretched polyethylene terephthalate

Polyethylene terephthalate

Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...

 (PET) and is used for its high tensile strength

Tensile strength

Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...

, chemical

Chemical stability

Chemical stability when used in the technical sense in chemistry, means thermodynamic stability of a chemical system.Thermodynamic stability occurs when a system is in its lowest energy state, or chemical equilibrium with its environment. This may be a dynamic equilibrium, where individual atoms...

 and dimensional

Shape

The shape of an object located in some space is a geometrical description of the part of that space occupied by the object, as determined by its external boundary – abstracting from location and orientation in space, size, and other properties such as colour, content, and material...

 stability

Strength of materials

In materials science, the strength of a material is its ability to withstand an applied stress without failure. The applied stress may be tensile, compressive, or shear. Strength of materials is a subject which deals with loads, deformations and the forces acting on a material. A load applied to a...

, transparency, reflectivity

Reflectivity

In optics and photometry, reflectivity is the fraction of incident radiation reflected by a surface. In general it must be treated as a directional property that is a function of the reflected direction, the incident direction, and the incident wavelength...

, gas and aroma barrier properties and electrical

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

 insulation

Electrical insulation

thumb|250px|[[Coaxial Cable]] with dielectric insulator supporting a central coreThis article refers to electrical insulation. For insulation of heat, see Thermal insulation...

.

A variety of companies manufacture boPET and other polyester films under different brand names. In the UK and US, the most well-known trade names are Mylar, Melinex and Hostaphan.

History

BoPET film was developed in the mid-1950s, originally by DuPont

DuPont

E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

 and Imperial Chemical Industries

Imperial Chemical Industries

Imperial Chemical Industries was a British chemical company, taken over by AkzoNobel, a Dutch conglomerate, one of the largest chemical producers in the world. In its heyday, ICI was the largest manufacturing company in the British Empire, and commonly regarded as a "bellwether of the British...

 (ICI). In 1960 and 1964, NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 launched the Echo satellite

Echo satellite

Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft was a metalized balloon satellite acting as a passive reflector of microwave signals. Communication signals were bounced off of them from one point on Earth to another.-Echo 1:NASA's Echo 1...

s, 100 feet (30.5 m) diameter balloons of metallized 0.005 inch (0.127 mm) thick boPET film.

Manufacture and properties

The manufacturing process begins with a film of molten polyethylene terephthalate

Polyethylene terephthalate

Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...

 (PET) being extruded

Plastics extrusion

Plastics extrusion is a high volume manufacturing process in which raw plastic material is melted and formed into a continuous profile. Extrusion produces items such as pipe/tubing, weather stripping, fence, deck railing, window frames, adhesive tape and wire insulation.-Process:In the extrusion of...

 onto a chill roll, which quenches it into the amorphous state. It is then biaxially oriented by drawing

Drawing (manufacturing)

Drawing is a metalworking process which uses tensile forces to stretch metal. It is broken up into two types: sheet metal drawing and wire, bar, and tube drawing. The specific definition for sheet metal drawing is that it involves plastic deformation over a curved axis...

. The most common way of doing this is the sequential process, in which the film is first drawn in the machine direction using heated rollers and subsequently drawn in the transverse direction, i.e. orthogonally

Orthogonality

Orthogonality occurs when two things can vary independently, they are uncorrelated, or they are perpendicular.-Mathematics:In mathematics, two vectors are orthogonal if they are perpendicular, i.e., they form a right angle...

 to the direction of travel, in a heated oven. It is also possible to draw the film in both directions simultaneously, although the equipment required for this is somewhat more elaborate. Draw ratios are typically around 3 to 4 in each direction.

Once the drawing is completed, the film is "heat set" or crystal

Crystal

A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

lized under tension in the oven at temperatures typically above 200 °C (392 °F). The heat setting step prevents the film from shrinking back to its original unstretched shape and locks in the molecular orientation in the film plane. The orientation of the polymer chains is responsible for the high strength and stiffness of biaxially oriented PET film, which has a typical Young's modulus

Young's modulus

Young's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...

 of about 4 GPa. Another important consequence of the molecular orientation is that it induces the formation of many crystal nuclei. The crystallites that grow rapidly reach the boundary of the neighboring crystallite and remain smaller than the wavelength of visible light. As a result, biaxially oriented PET film has excellent clarity, despite its semicrystalline structure.

If it were produced without any additives, the surface of the film would be so smooth that layers would adhere strongly to one another when the film is wound up, similar to the sticking of clean glass plates when stacked. To make handling possible, microscopic inert inorganic particles are usually embedded in the PET to roughen the surface of the film.

Biaxially oriented PET film can be metallized

Metallised film

Metallised films are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost...

 by vapor deposition

Vapor deposition

Vapor deposition can refer to:* Chemical vapor deposition* Physical vapor deposition...

 of a thin film  of evaporated

Evaporation

Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

 aluminum, gold

Gold

Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

, or other metal onto it. The result is much less permeable to gases (important in food packaging

Modified atmosphere

Modified atmosphere is the practice of modifying the composition of the internal atmosphere of a package in order to improve the shelf life....

) and reflects up to 99% of light, including much of the infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 spectrum. For some applications like food packaging, the aluminized boPET film can be laminated with a layer of polyethylene

Polyethylene

Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...

, which provides sealability and improves puncture resistance

Puncture resistance

Puncture resistance denotes the relative ability of a material to inhibit the progression of a tear once it has been pierced by a cut or a nick. Tests devised to measure puncture resistance are generally application-specific, covering items such as roofing and packaging materials, protective...

. The polyethylene side of such a laminate appears dull and the PET side shiny.

Other coatings, such as conductive indium tin oxide

Indium tin oxide

Indium tin oxide is a solid solution of indium oxide and tin oxide , typically 90% In2O3, 10% SnO2 by weight. It is transparent and colorless in thin layers while in bulk form it is yellowish to grey...

 (ITO), can be applied to boPET film by sputter deposition

Sputter deposition

Sputter deposition is a physical vapor deposition method of depositing thin films by sputtering, that is ejecting, material from a "target," that is source, which then deposits onto a "substrate," such as a silicon wafer...

.

Flexible packaging and food contact applications

• Laminates containing metallized boPET foil (In technical language called printin or laminate web substrate) protect food against oxidation and aroma loss, achieving long shelf life
  Shelf life
  Shelf life is the length of time that food, drink, medicine, chemicals, and many other perishable items are given before they are considered unsuitable for sale, use, or consumption...
  
  . Examples are coffee "foil" packaging and pouches for convenience foods.
• White boPET web substrate is used as lidding for dairy goods such as yoghurt
  Yoghurt
  Yoghurt, yogurt or yogourt is a dairy product produced by bacterial fermentation of milk. The bacteria used to make yoghurt are known as "yoghurt cultures"...
  
  .
• Clear boPET web substrate is used as lidding for fresh or frozen ready meals. Due to its excellent heat resistance, it can remain on the package during microwave or oven heating.
• Roasting bags
• Metallised film
  Metallised film
  Metallised films are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost...
  
  s

Covering over paper

• A clear overlay on a map
  Map
  A map is a visual representation of an area—a symbolic depiction highlighting relationships between elements of that space such as objects, regions, and themes....
  
  , on which notations, additional data
  Data
  The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
  
  , or copied data, can be drawn without damaging the map
• Metallized boPET is used as a mirror-like decorative surface on some book covers, T-shirts, and other flexible cloths.
• Protective covering over buttons/pins/badge
  Badge
  A badge is a device or fashion accessory, often containing the insignia of an organization, which is presented or displayed to indicate some feat of service, a special accomplishment, a symbol of authority granted by taking an oath , a sign of legitimate employment or student status, or as a simple...
  
  s
• The glossy top layer of a Polaroid
  Polaroid Corporation
  Polaroid Corporation is an American-based international consumer electronics and eyewear company, originally founded in 1937 by Edwin H. Land. It is most famous for its instant film cameras, which reached the market in 1948, and continued to be the company's flagship product line until the February...
  
   SX-70
  Polaroid SX-70
  The SX-70 is a folding single lens reflex Land Camera which was produced by the Polaroid Corporation from 1972-1981.- History :Though Polaroid had considered a Henry Dreyfus-designed SLR for its Colorpack film, the SX-70 was the first instant SLR and the first camera to use Polaroid's new SX-70...
  
   photographic print
• As a backing for very fine sandpaper
  Sandpaper
  Sandpaper, also known as glasspaper, is a heavy paper with abrasive material attached to its surface.Sandpaper is part of the "coated abrasives" family of abrasive products. It is used to remove small amounts of material from surfaces, either to make them smoother , to remove a layer of material...
  
  
• boPET film is used in bagging comic books, in order to best protect them during storage from environmental conditions (moisture, heat, and cold) that would otherwise cause paper to slowly deteriorate over time. This material is used for archival quality storage of documents by the Library of Congress
  Library of Congress
  The Library of Congress is the research library of the United States Congress, de facto national library of the United States, and the oldest federal cultural institution in the United States. Located in three buildings in Washington, D.C., it is the largest library in the world by shelf space and...
  
   and several major library comic book research collections, including the Comic Art Collection at Michigan State University
  Michigan State University
  Michigan State University is a public research university in East Lansing, Michigan, USA. Founded in 1855, it was the pioneer land-grant institution and served as a model for future land-grant colleges in the United States under the 1862 Morrill Act.MSU pioneered the studies of packaging,...
  
  . While boPET is widely (and effectively) used in this archival sense, it is not immune to the effects of fire and heat and could potentially melt, depending on the intensity of the heat source, causing further damage to the encased item.
• For protecting the spine of important documents, such as medical records.

Insulating material

• An electrical insulating
  Electrical insulation
  thumb|250px|[[Coaxial Cable]] with dielectric insulator supporting a central coreThis article refers to electrical insulation. For insulation of heat, see Thermal insulation...
  
   material
• Insulation
  Thermal insulation
  Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...
  
   for houses and tents, reflecting thermal radiation
• Five layers of metallized boPET film in NASA's spacesuits make them radiation
  Radiation
  In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
  
   resistant and keep astronauts warm.
• Metallized boPET film "emergency blankets
  Space blanket
  A space blanket is a blanket used in emergencies to reduce heat loss in a person's body caused by thermal radiation, water evaporation and convection.-Manufacturing:First developed by NASA in 1964 for the US space program, the material consists of a...
  
  " conserve a shock victim's body heat.
• As a thin strip to form an airtight seal between the control surfaces and adjacent structure of aircraft, especially glider
  Glider aircraft
  Glider aircraft are heavier-than-air craft that are supported in flight by the dynamic reaction of the air against their lifting surfaces, and whose free flight does not depend on an engine. Mostly these types of aircraft are intended for routine operation without engines, though engine failure can...
  
  s.
• Light insulation for indoor gardening.
• Wildland fire shelters.
• Proximity (aluminized) suits used by AR-FF fire fighters for protection from the high amount of heat release from fuel fires.
• Aluminized boPET films are no longer used as thermal and acoustic insulation in aircraft since they were found to have been a factor in the Swissair Flight 111 crash
  Swissair Flight 111
  Swissair Flight 111 was a Swissair McDonnell Douglas MD-11 on a scheduled airline flight from John F. Kennedy International Airport in New York City, United States to Cointrin International Airport in Geneva, Switzerland...
  
  . The accident investigation showed that the aluminum layer prevents the film from self-extinguishing in a fire under the conditions in aircraft.

Solar and marine applications

• Metallized boPET is intended to be used for solar sail
  Solar sail
  Solar sails are a form of spacecraft propulsion using the radiation pressure of light from a star or laser to push enormous ultra-thin mirrors to high speeds....
  
  s as an alternative means of propulsion
  Spacecraft propulsion
  Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
  
   for spacecraft
  Spacecraft
  A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
  
   such as Cosmos 1
  Cosmos 1
  Cosmos 1 was a project by Cosmos Studios and The Planetary Society to test a solar sail in space. As part of the project, an unmanned solar sail spacecraft christened Cosmos 1 was launched into space at 15:46:09 EDT on June 21, 2005 from the submarine Borisoglebsk in the Barents Sea...
  
  
• Metallized boPET solar
  Sun
  The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
  
   curtains reflect sunlight and heat away from windows.
• Aluminized, as an inexpensive solar eclipse
  Solar eclipse
  As seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun as viewed from a location on Earth. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. At least...
  
   viewer, although care must be taken, because invisible fissures can form in the metal film, reducing its effectiveness.
• High performance sail
  Sail
  A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
  
  s for sailboat
  Sailboat
  A sailboat or sailing boat is a boat propelled partly or entirely by sails. The term covers a variety of boats, larger than small vessels such as sailboards and smaller than sailing ships, but distinctions in the size are not strictly defined and what constitutes a sailing ship, sailboat, or a...
  
  s and hanggliders
• Use boPET films as the back face of the PV modules in solar panels
• Metallized boPET as a reflector material for solar cooking stoves

Science

• Amateur and professional visual and telescopic solar filters. BoPET films are often annealed to a glass element to improve thermal conductivity, and guarantee the necessary flat surface needed for even telescopic solar observation. Manufacturers will typically utilise films with thicknesses of 280 um, in order to give the films better resilience. 250 um thickness films with a heavy aluminium coating are generally preferred for naked-eye Solar observation during eclipses.
• Films in annular ring mounts on gas-tight cells, will readily deform into spherical mirrors. Photomultiplier
  Photomultiplier
  Photomultiplier tubes , members of the class of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum...
  
   cosmic-ray observatories often make use of these mirrors for inexpensive large (1.0 m and above), lightweight mirror surfaces for sky-sector low and medium energy cosmic ray research.
• As a light diaphragm material separating gases in hypersonic shock and expansion tube facilities.
• As a beamsplitter in Fourier transform infrared spectroscopy
  Fourier transform infrared spectroscopy
  Fourier transform infrared spectroscopy is a technique which is used to obtain an infrared spectrum of absorption, emission, photoconductivity or Raman scattering of a solid, liquid or gas. An FTIR spectrometer simultaneously collects spectral data in a wide spectral range...
  
  , typically with laser
  Laser
  A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
  
   applications. Film thicknesses are often in the 500 micrometre range.
• Coating around hematocrit tubes
  Hematocrit
  The hematocrit or packed cell volume or erythrocyte volume fraction is the percentage of the concentration of red blood cells in blood. It is normally about 45% for men and 40% for women...
  
  .
• Insulating material for a cryocooler radiation shield.
• As a window material to confine gas in detectors and targets in nuclear physics
  Nuclear physics
  Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those...
  
  .

Electronic and acoustic applications

• Carrier for flexible printed circuits
• Very thin boPET film is often used as the diaphragm
  Diaphragm (acoustics)
  In the field of acoustics, a diaphragm is a transducer intended to faithfully inter-convert mechanical motion and sound. It is commonly constructed of a thin membrane or sheet of various materials. The varying air pressure of the sound waves imparts vibrations onto the diaphragm which can then be...
  
   material in electrostatic loudspeaker
  Electrostatic loudspeaker
  An electrostatic loudspeaker is a loudspeaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.-Design and functionality:...
  
  s and electret microphone
  Electret microphone
  An electret microphone is a type of condenser microphone, which eliminates the need for a polarizing power supply by using a permanently charged material....
  
  s.
• boPET film has been used in the production of banjo
  Banjo
  In the 1830s Sweeney became the first white man to play the banjo on stage. His version of the instrument replaced the gourd with a drum-like sound box and included four full-length strings alongside a short fifth-string. There is no proof, however, that Sweeney invented either innovation. This new...
  
   & drumhead
  Drumhead
  A drumhead is a membrane stretched over one or both of the open ends of a drum. The drumhead is struck with sticks, mallets, or hands so that it vibrates and the sound resonates through the drum.-History:...
  
  s since 1958 due to its durability and acoustical properties when stretched over the bearing edge of the drum. They are made in single- and double-ply versions, with each ply being 2 mil in thickness, with a clear
  Clear
  Clear may refer to:* Clear, Alaska is an unincorporated community in Denali Borough, Alaska, United States-Music:*Clear , a 1969 album by Spirit*Clear , a 1995 album by Bomb the Bass...
  
   or opaque
  Opacity (optics)
  Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc...
  
   surface, originally used by the company Evans
  D'Addario
  D'Addario is a manufacturer of musical instrument strings, primarily guitar strings, currently headquartered in Farmingdale, Long Island, New York...
  
  .
• boPET film is used as the substrate in practically all magnetic recording tape
  Magnetic tape
  Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
  
  s and floppy disk
  Floppy disk
  A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
  
  s.
• Metallized boPET film, along with other plastic films, is used as a dielectric
  Dielectric
  A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material, as in a conductor, but only slightly shift from their average equilibrium positions causing dielectric...
  
   in foil capacitor
  Capacitor
  A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...
  
  s.
• Clear boPET bags are used as packaging for audio media such as compact discs and vinyl records.

Graphic arts

• Before the widespread adoption of CAD, engineering plans or architectural drawing
  Architectural drawing
  An architectural drawing or architect's drawing is a technical drawing of a building that falls within the definition of architecture...
  
  s were plotted onto sheets of boPET film. The boPET sheets become legal documents from which copies or blueprint
  Blueprint
  A blueprint is a type of paper-based reproduction usually of a technical drawing, documenting an architecture or an engineering design. More generally, the term "blueprint" has come to be used to refer to any detailed plan....
  
  s are made. boPET sheets are more durable and can withstand more handling than bond paper
  Bond paper
  Bond paper is a high quality durable writing paper similar to bank paper but having a weight greater than 50 g/m2. The name comes from it having originally been made for documents such as government bonds. It is now used for letterheads, other stationery and as paper for electronic printers...
  
  . This is no longer necessary, as traditional diazo
  Diazo
  Diazo refers to a type of organic compound called diazo compound that has two linked nitrogen atoms as a terminal functional group. The general formula is R2C=N2. The simplest example of a diazo compound is diazomethane...
  
   "blueprint
  Whiteprint
  Whiteprint is the commercial terminology to describe document reproduction using the diazo chemical process. It is also known as the blue-line or blue-line process...
  
  " duplication has fallen out of use.
• Overhead transparency film for photocopiers or laser printers (boPET film withstands the high heat).

Other

• Route information signs, called rollsigns or destination blinds, displayed by public transport vehicles
• For materials in kites
• Covering glass
  Glass
  Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
  
   to decrease probability of shattering
• In theatre effects as confetti
  Confetti
  Confetti is a multitude of pieces of paper, mylar or metallic material which is usually thrown at parades and celebrations, especially weddings . Confetti is made in a variety of colors, and commercially available confetti is available in imaginative shapes...
  
  .
• As the adhesive strip to attach the string to a teabag
• One of the many materials used as windsavers or valves for valved harmonicas
• On farmland, highly reflective aluminized PET film ribbons are tied to the plants to create shimmers from the sun for an effect similar to a scarecrow
  Scarecrow
  A scarecrow is, essentially, a decoy, though traditionally, a human figure dressed in old clothes and placed in fields by farmers to discourage birds such as crows or sparrows from disturbing and feeding on recently cast seed and growing crops.-History:In Kojiki, the oldest surviving book in Japan...
  
  .
• Measuring tape
• Protecting pinball
  Pinball
  Pinball is a type of arcade game, usually coin-operated, where a player attempts to score points by manipulating one or more metal balls on a playfield inside a glass-covered case called a pinball machine. The primary objective of the game is to score as many points as possible...
  
   machine playfields from wear

External links

• Plastics: Background Information for Teachers. by The American Plastics Council (HTML format) or (PDF format) - 1.9MB), which includes the "chasing arrow
  Recycling symbol
  The universal recycling symbol or in Unicode) is an internationally recognized symbol used to designate recyclable materials. It is composed of three mutually chasing arrows that form a Möbius strip ....
  
  " recycling symbols (PET is #1) and a description of plastics.
• An interesting toy has been developed using boPET and a stick-shaped Van de Graff generator.