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POLYETHYLENE TEREPHTHALATE = POLYESTER
CAS Number: 25038-59-9
MDL number: MFCD00084422
Molecular Formula: (C10H8O4)n
Polyethylene terephthalate (PET) (also abbreviated PETE) is short for polyethylene terephthalate, the chemical name for polyester.
The basic building blocks of PET are ethylene glycol and terephthalic acid, which are combined to form a polymer chain.
The resulting spaghetti-like strands of PET are extruded, quickly cooled, and cut into small pellets.
The resin pellets are then heated to a molten liquid that can be easily extruded or molded into items of practically any shape.
PET was first synthesized in North America in the mid-1940s by DuPont chemists searching for new synthetic fibers.
In the late 1950s, researchers found a way to stretch a thin extruded sheet of PET in two directions to create PET film, which is now used extensively for video, photo and packaging films.
In the early 1970s, the technology was developed for blow-stretch molding PET into bottles.
The PET bottle was patented in 1973.
PET is approved as safe for contact with foods and beverages by the FDA and health-safety agencies throughout the world.
The safety of PET for food, beverage, pharmaceutical and medical applications has been repeatedly demonstrated through extensive studies, regulatory approvals, testing, and its widespread acceptance for more than 30 years.
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family.
Bio-PET is the bio-based counterpart of PET.
The majority of the world's PET production is for synthetic fibres (in excess of 60%), with bottle production accounting for about 30% of global demand.
In the context of textile applications, PET is referred to by PETs common name, polyester, whereas the acronym PET is generally used in relation to packaging.
Polyester makes up about 18% of world polymer production and is the fourth-most-produced polymer after polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC).
PET consists of polymerized units of the monomer ethylene terephthalate, with repeating (C10H8O4) units.
PET is commonly recycled, and has the digit 1 (♳) as its resin identification code (RIC).
Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer.
The semicrystalline material might appear transparent (particle size less than 500 nm) or opaque and white (particle size up to a few micrometers) depending on its crystal structure and particle size.
The monomer bis(2-hydroxyethyl) terephthalate can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct (this is also known as a condensation reaction), or by transesterification reaction between ethylene glycol and dimethyl terephthalate (DMT) with methanol as a byproduct.
Polymerization is through a polycondensation reaction of the monomers (done immediately after esterification/transesterification) with water as the byproduct.
Polyethylene terephthalate (PET or PETE), a strong, stiff synthetic fibre and resin and a member of the polyester family of polymers.
PET is produced by the polymerization of ethylene glycol and terephthalic acid.
Ethylene glycol is a colourless liquid obtained from ethylene, and terephthalic acid is a crystalline solid obtained from xylene.
When heated together under the influence of chemical catalysts, ethylene glycol and terephthalic acid produce PET in the form of a molten, viscous mass that can be spun directly to fibres or solidified for later processing as a plastic.
In chemical terms, ethylene glycol is a diol, an alcohol with a molecular structure that contains two hydroxyl (OH) groups, and terephthalic acid is a dicarboxylic aromatic acid, an acid with a molecular structure that contains a large six-sided carbon (or aromatic) ring and two carboxyl (CO2H) groups.
Under the influence of heat and catalysts, the hydroxyl and carboxyl groups react to form ester (CO-O) groups, which serve as the chemical links joining multiple PET units together into long-chain polymers.
Water is also produced as a by-product.
The presence of a large aromatic ring in the PET repeating units gives the polymer notable stiffness and strength, especially when the polymer chains are aligned with one another in an orderly arrangement by drawing (stretching).
At a slightly higher molecular weight, PET is made into a high-strength plastic that can be shaped by all the common methods employed with other thermoplastics.
PET films are produced by extrusion.
Molten PET can be blow-molded into transparent containers of high strength and rigidity that are also virtually impermeable to gas and liquid.
In this form, PET has become widely used in carbonated-beverage bottles and in jars for food processed at low temperatures. The low softening temperature of PET—approximately 70 °C (160 °F)—prevents PET from being used as a container for hot foods.
PET was first prepared in England by J. Rex Whinfield and James T. Dickson of the Calico Printers Association during a study of phthalic acid begun in 1940.
Because of wartime restrictions, patent specifications for the new material were not immediately published.
Production by Imperial Chemical of its Terylene-brand PET fibre did not begin until 1954.
Meanwhile, by 1945 DuPont had independently developed a practical preparation process from terephthalic acid, and in 1953 the company began to produce Dacron fibre.
PET soon became the most widely produced synthetic fibre in the world.
In the 1970s, improved stretch-molding procedures were devised that allowed PET to be made into durable crystal-clear beverage bottles—an application that soon became second in importance only to fibre production.
Polyethylene terephthalate (PET) is a chemically stable polyester, and PETs use has risen dramatically in the last few decades with a multitude of applications, ranging from food and drink containers to the manufacture of electronic components and as fibers in clothes.
PET was first polymerized in the 1940s by DuPont chemists looking to develop polymer materials for use as textile fibers.
Polyethylene terephthalate is produced from the synthesis of ethylene glycol and terephthalic acid.
Even without additives to increase PETs strength, PET is still very strong for PETs light weight.
This means that less material is required for uses such as plastic film for packaging.
This means less fuel is required for shipping when using PET packaging.
Additionally, although the material is petroleum based, approximately 40% of the energy is stored internal and is available a second time once recycled.
Polyester polymers formed from terephthalic acid or its esters and ethylene glycol.
They can be formed into tapes, films or pulled into fibers that are pressed into meshes or woven into fabrics.
PET plastics or polyethylene terephthalate is used in many different products.
The properties of PET make Polyethylene terephthalate ideal for a number of different uses and these advantages make
Polyethylene terephthalate one of the most common plastics available today.
Understanding more about the history of PET, as well as the chemical properties, will allow you to appreciate this plastic even more.
In addition, most communities recycle this type of plastic, which allows Polyethylene terephthalate to be used again and again.
Polyester is a category of polymers that have a specific structure.
As a material, Polyester usually refers to a the type of polyester called POLYETHYLENE TEREPHTHALATE (PET)
Polyethylene terephthalate is the most common thermoplastic polymer resin of the polyester family and is used to make.
Polyethylene Terephthalate (PET) is a form of polyester that is used in the production of plastic bottles and containers for food, beverages, and cosmetics.
Polyethylene Terephthalate was patented in 1973 by chemist Nathaniel Wyeth by combining modified ethylene glycol and purified terephthalic acid.
Polyethylene Terephthalate is popular among manufacturers for PETs ease of production, transparency, lightweight, and the fact that is easily recyclable.
Polyethylene terephthalate (PET) resin is used for various of applications, such as packaging, industrial parts and sheets etc.
PET has excellent characteristics such as high transparency, high mechanical and excellent gas barrier properties.
Polyethylene Terephthalate, or PET for short, is a type of plastic that is in common usage in many products today and is easily recyclable.
PET is predominantly produced for the textiles industry as ‘polyester’, but this article will focus on the more pure form used in packaging.
Primarily used in plastic drinks bottles, PET is recognisable by the ‘spot’ on the base of the bottle, composed of moulded plastic.
PET is a polymer.
This means PET’s a macromolecule made out of thousands of repeating units called monomers.
To produce PET chemists use two different kinds of monomers: terephthalic acid and ethylene glycol.
Both units undergo a reaction called esterification, where an organic acid and an alcohol combine to form an ester and water.
Esters are usually compounds with nice and fruity smells.
But PET is not a normal ester – PET’s a polymer, hence a poly-ester – and properties are very different.
PET can, of course, be spun into fibres.
Check the labels on your sport clothes – if they say ‘polyester’ then it’s probably PET (or maybe another close family member).
But PET is more versatile – Polyethylene terephthalate can be crystallised into a very light, resistant material, ideal for making bottles.
Polyethylene terephthalate’s cheaper than glass, PET’s flexible, less fragile, and Polyethylene terephthalate can also be reused thousands of times .
PET’s also much lighter than glass, and costs less to transport, so Polyethylene terephthalate makes sense that PET bottles are now everywhere.
Polyethylene Terephthalate, or PET, is a popular resin used in packaging.
PET is a synthetic resin produced by the polymerization of ethylene glycol and terephthalic acid.
PET is spun into fibers for permanent press fabrics, blow-molded into disposable beverage bottles, and even extruded into photographic film.
PET’s used in polyester fibers for clothing, containers for liquids and foods, and thermoforming for manufacturing, to name a few.
PET is a good barrier for both water and gas, offering resistance to mineral oils, solvents and acids.
PET is also easily recognized by consumers as the material that’s used to make many household and food products.
When’s the last time you drank from a water bottle, used ketchup for those delicious French fries at lunch, or used detergent to wash your dishes?
Odds are good that the packaging was made using PET.
Polyethylene terephthalate (PET) is a highly recyclable plastic resin and a form of polyester.
Polyethylene terephthalate is a polymer created by the combination of two monomers: modified ethylene glycol and purified terephthalic acid.
Polyethylene terephthalate was first synthesized in North America by Dupont chemists during the 1940s.
Prized for its strength, thermo-stability, and transparency, PET is a popular choice for packaging.
PET also is inexpensive, lightweight, resealable, shatter-resistant, and recyclable.
PET is a high-molecular polymer based on a complex polyester.
Polyethylene terephthalate is a product of interaction between terephthalic acid and ethylene glycol, which then undergoes polycondensation with a catalyst and crystallisation until Polyethylene terephthalate acquires the properties necessary for making packaging items
Nowadays disposable PET bottles only weigh about 20 g to 30 g.
A glass bottle with a comparable content would weigh around 25 times more.
Returnable PET bottles are a little heavier due to their somewhat thicker walls and more robust base.
The low weight has a positive effect on transport costs.
Moreover disposable PET bottles are conveyed to the filling plants as preforms and only blow-moulded to fi nished bottles there.
This makes PET possible to greatly improve the payload of the transport vehicles.
Polyethylene Terephthalate, commonly referred to as PET (or PETE) is a thermoplastic polymer resin.
PET begins as white resin pellets that become transparent when heated and cured into a desired plastic part.
We interact with this versatile material in our everyday lives from food and beverage packaging to personal care and beauty containers.
This widely used plastic comes in five different variations with unique attributes: OPET, PETE, EPETE, PETG and PCTG
PETE (or PET):
PETE is the most common variation of the thermoplastic polymer resin.
The clarity of PET is considered to be the best of all plastics with very good chemical resistance.
PETE is formed into containers via 1-Step or 2-Step Injection Blow Molding.
1-Step IBM is considered optimal to maintain the clarity and finish of the final bottle as the injection molded Preform is transferred immediately to the Blowing station to be formed into the final container, vs. the 2-Step IBM process, where the Preform is often tumble packed for storage and transferred to a different machine for blow molding at a later date, this results in minor abrasions, nicks and scratches that are avoided in the 1-Step process.
Here are some of the advantages of running PETE through a 1-Step process:
-Blemish Free Containers
-Lack of Transfer Ring
-Thread can be orientated with bottle cap
OPET:
The “O” in OPET stands for oriented.
PET is oriented biaxially during the 2-Step Injection Stretch Blow Moulding process.
When PET is in the preform stage, the polymer molecule starts as an unbalanced chain, when
OPET is heated and stretched with a pin the molecule is oriented, or arranged, in parallel with the direction OPET is stretched.
After the preform is stretched with a pin OPET is blown to the dimensions of the final container.
Oriented PET has the benefit of increased durability, clarity as well as better barrier properties.
EPET:
PETE is an extrusion grade variation of the base resin PET.
The molecular weight is higher in this form of PET allowing a parison extrusion.
PET containers that require a handle will often be formed from this variation, for example, the clear orange juice containers with handles you’d find at the grocery store.
The chemical resistance and clarity is comparable with PETE.
PETG:
Polyethylene Terephthalate Glycol (PETG) is an amorphous variation of PET.
PETG cannot be oriented and therefore you will not find pre-forms of this type of resin.
Extrusion, Injection Blow Moulding and 1-Step Injection Stretch Blow Moulding are all possible for PETG, PETG is also used frequently for 3D printing.
Clarity and chemical resistance are considered good when compared to the previous three variations, however PETG has poor impact resistance.
PCTG:
PCTG is another amorphous form of PET.
Like PETG, PCTG cannot be oriented, PCTG is suitable for Extrusion, Injection and 1-Step Injection Stretch Blow Moulding.
Due to PCTG's excellent impact resistance and clarity PCTG is commonly used for products requiring higher impact resistance.
PCTG resin is used often in cosmetic packaging components.
Polyethylene terephthalate or PET is common for good reason.
Polyethylene terephthalate is a highly versatile material, and PET’s lightweight, safe, and easy to recycle.
The properties that manufacturers love about PET are:
-Polyethylene terephthalate provides a good protective barrier and can resist micro-organisms.
-PET has good chemical resistance meaning Polyethylene terephthalate will not react with foods and beverages stored inside.
-Polyethylene terephthalate is very strong and will hold its shape, protecting the substances inside.
-PET’s lightweight, making Polyethylene terephthalate economical for packaging.
-Polyethylene terephthalate can be very clear and smooth – easy to see what’s inside, or Polyethylene terephthalate can be colored easily.
-Polyethylene terephthalate can be reused and recycled.
Polyethylene terephthalate is a condensation polymer of ethylene glycol and terephthalic acid.”
The by-product of the reaction to create this compound is water so it is an example of condensation or step-growth polymerization.
On the basis of mechanism, there are two types of polymerization; step-growth and chain-growth polymerization.
Chain growth polymerization is also called as addition polymerization in which monomer units are bonded with each other through their multiple bonds.
For example polymerization of ethylene leads to the formation of polyethylene polymer which is also known as polythene.
This polymerization is a three-step process.
The first step is the formation of free radicals in the presence of some initiator like peroxide.
We know that a free-radical is a chemical species with a free electron.
These free radicals involve initiation steps and form new free radicals with monomer units which begin the polymer chain.
The double bond of monomer units breaks and attach with free radical to form new free radicals.
PET (Polyethylene Terephthalate) film is a thermoplastic polymer that can be amorphous, crystalline, or a mixture of both depending on how PET’s processed.
If the hydrocarbons used are ethylene glycol and terephthalic acid, the type of polymer produced will be polyethylene terephthalate, or PET for short.
PET is one of the most widespread types of plastic.
In fact, PET is the single most common type of plastic by volume.
First invented in the midst of World War II and steadily improved in the following decades, PET is strong, lightweight, and transparent.
PET is also break-resistant and waterproof.
Perhaps most crucially, PET is the ideal plastic to use for packaging foods and beverages.
Another advantage that polyethylene terephthalate has over other plastic resins is PETs sustainability.
PET is the most widely recycled plastic in the world, and a new PET container can be produced with 100% recycled PET.
PET can also be recycled again and again.
Compare this to other plastics like polystyrene or polyamide plastic 6,6.
These plastics are often mixed with impurities when they reach the recycling plant and can typically be recycled only once. After that, quality declines significantly.
Since plastics are made of hydrocarbons, and hydrocarbons occur within the Earth’s oil reserve, they are a limited and slowly-replenished resource.
There is a limit to how much plastic resin that can be manufactured.
This makes PET’s ability to be recycled multiple times very attractive from an environmental and financial point of view. Overall, given PET resin’s versatile, food-safe, and environmentally-friendly properties, PET is easy to see why they are so popularly used.
PET (polyethylene terephthalate, semicrystalline) is a strong, stiff engineering plastic that is often used for food processing machinery applications where low moisture absorption, low thermal expansion, resistance to staining, or resistance to cleaning chemicals is required.
PET is a polymer consisting of ethylene glycol and terephthalic acid, two materials that are combined to create hard plastic pellets.
Those pellets can then be melted and shaped into nearly any form, which will then cool and harden into a tough, shatter-proof material.
In PETs natural state, PET is highly flexible, colorless, and semi-crystalline.
Depending on how PET’s processed, PET can be rigid to semi-rigid.
In fact, PET is the most recycled plastic in the world.
This material can be easily converted into other forms through washing and re-melting.
Popular recycled PET products include carpet, clothing, rope, fiberfill for sleeping bags or winter jackets, and construction materials.
In addition to being recyclable, PET is energy-efficient to create, use, and transport.
PETs raw materials are derived from crude oil and natural gas, but PET still maintains a favorable sustainability profile when compared to glass or aluminum.
PET requires less fuel to transport than other materials of similar strength, making PET an appealing option for many manufacturers.
In addition to being lightweight, sturdy, and recyclable, PET is favored for numerous applications because of its safety.
The material is food- and beverage-safe, resistant to attacks by microorganisms, and chemical-resistant.
In addition, PET exhibits low moisture absorption and excellent wear characteristics, making PET safe to contain and transport food and beverages.
PET also has low gas permeability, excellent electrical insulation, a broad range of use temperatures, and excellent resistance to alcohols, oils, greases, and diluted acids.
What’s more, PET doesn’t break or fracture, making PET a favorable glass replacement for many applications.
PET is the acronym for a very versatile and sophisticated plastic called Polyethylene Terephthalate.
For sound economic and safety reasons, PET’s the plastic used to make the most common container in the soft drink market today: the plastic bottle.
PET is sometimes referred to as polyester and is made from mono-ethylene glycol (MEG) and purified terephthalic acid (PTA), which is derived from crude oil and natural gas.
These two crude oil derivatives are reacted under a controlled set of conditions to form a polymer.
Then, in a honey-like form, this polymer is extruded through a die-plate, cast into spaghetti-like strands, and cut into pellets.
These pellets are crystallised and polymerised for a second time to increase their strength and to remove volatiles.
Polyethylene terephthalate (PET) is the most important commercial polyester polymer.
Since PET is stronger than cotton and cellulose, yet mixes well with cotton fibers, PET is used in fibers.
Cloth made from these fibers is resistant to creasing.
Polyethylene terephthalate (PET) is a polymer material with many characteristics that make it suitable for product packaging. PET is the most widely recycled plastic in the world.
PET is clear, durable, chemically inert, eco-friendly, and lightweight, which allows for the manufacture of large but light containers that are strong and safe.
Packaging made from PET can also be easily decorated with printed designs or effects to suit different product or brand aesthetics.
Polyethylene Terephthalate (PET) is a polyester-based material that combines excellent mechanical, electrical and thermal properties with very good chemical resistance and dimensional stability.
PET also has low moisture absorption features and good flow properties, making PET a great material to use for waterproof containers such as food and beverage storage.
PET is a great material to use for making lightweight products such as potted planters, insulated bottles, or tupperware.
USES and APPLICATIONS of POLYETHYLENE TEREPHTHALATE:
-PET is a clear, strong, and lightweight plastic that is widely used for packaging foods and beverages, especially convenience-sized soft drinks, juices and water.
-Polyethylene terephthalate is also popular for packaging salad dressings, peanut butter, cooking oils, mouthwash, shampoo, liquid hand soap, window cleaner, even tennis balls.
-Special grades of PET are used for carry-home food containers and prepared food trays that can be warmed in the oven or microwave.
-Today, more than half of the world's synthetic fiber is made from PET, which is called "polyester" when used for fiber or fabric applications.
-When used for containers and other purposes, Polyethylene terephthalate is called PET or PET resin.
-Because of PET's unique properties, Polyethylene terephthalate is rapidly becoming the world's preferred packaging material for foods and beverages.
-Like glass, Polyethylene terephthalate is a very strong and inert material that does not react with foods, is resistant to attack by micro-organisms, and will not biologically degrade.
But unlike glass, PET is extremely lightweight, easy and efficient to transport, and shatterproof.
-Polyethylene terephthalate is used in fibres for clothing, containers for liquids and foods, and thermoforming for manufacturing, and in combination with glass fibre for engineering resins.
-Plastic bottles made from PET are widely.
For certain specialty bottles, such as those designated for beer containment, PET sandwiches an additional polyvinyl alcohol (PVOH) layer to further reduce PETs oxygen permeability.
-Biaxially oriented PET film (often known by one of its trade names, "Mylar") can be aluminized by evaporating a thin film of metal onto PET to reduce PETs permeability, and to make PET reflective and opaque (MPET).
These properties are useful in many applications, including flexible food packaging and thermal insulation (such as space blankets).
Because of PETs high mechanical strength, PET film is often used in tape applications, such as the carrier for magnetic tape or backing for pressure-sensitive adhesive tapes.
-Non-oriented PET sheet can be thermoformed to make packaging trays and blister packs.
If crystallizable PET is used, the trays can be used for frozen dinners, since they withstand both freezing and oven baking temperatures.
Both amorphous PET and BoPET are transparent to the naked eye.
Color-conferring dyes can easily be formulated into PET sheet.
-When filled with glass particles or fibres, PET becomes significantly stiffer and more durable.
-PET is also used as a substrate in thin film solar cells.
-PET is also used as a waterproofing barrier in undersea cables.
-Terylene (a trademark formed by inversion of (polyeth)ylene ter(ephthalate)) is also spliced into bell rope tops to help prevent wear on the ropes as they pass through the ceiling.
-PET is used since late 2014 as liner material in type IV composite high pressure gas cylinders.
PET works as a much better barrier to oxygen than earlier used (LD)PE.
-PET is used as a 3D printing filament, as well as in the 3D printing plastic PETG
-PET is spun into fibres for permanent-press fabrics and blow-molded into disposable beverage bottles.
-In semicrystalline form, PET is made into a high-strength textile fibre marketed.
The stiffness of PET fibres makes them highly resistant to deformation, so they impart excellent resistance to wrinkling in fabrics.
PET fibres are often used in durable-press blends with other fibres such as rayon, wool, and cotton, reinforcing the inherent properties of those fibres while contributing to the ability of the fabric to recover from wrinkling.
-PET is also made into fibre filling for insulated clothing and for furniture and pillows.
When made in very fine filaments, PET is used in artificial silk, and in large-diameter filaments PET is used in carpets.
Among the industrial applications of PET are automobile tire yarns, conveyor belts and drive belts, reinforcement for fire hoses and garden hoses, seat belts (an application in which it has largely replaced nylon), nonwoven fabrics for stabilizing drainage ditches, culverts, and railroad beds, and nonwovens for use as diaper topsheets and disposable medical garments.
PET is the most important of the synthetic fibres in weight produced and in value.
-PET is the most widely recycled plastic.
PET bottles and containers are commonly melted down and spun into fibres for fibrefill or carpets.
When collected in a suitably pure state, PET can be recycled into its original uses, and methods have been devised for breaking the polymer down into its chemical precursors for resynthesizing into PET.
The recycling code number for PET is 1.
-Because Polyethylene Terephthalate is an excellent water and moisture barrier material, plastic bottles made from PET are widely used for mineral water and carbonated soft drinks.
PETs high mechanical strength, makes Polyethylene Terephthalate films ideal for use in tape applications.
Non-oriented PET sheet can be thermoformed to make packaging trays and blisters.
PETs chemical inertness, together with other physical properties, has made PET particularly suitable for food packaging applications.
Other packaging applications include rigid cosmetic jars, microwavable containers, transparent films, etc.
-PET monofilament is mainly used for making mesh fabrics for screen-printing, filter for oil and sand filtration, bracing wires for agricultural applications (greenhouses etc.), woven/knitting belt, filter cloth, and other such industrial applications.
-PET has wide applications in textile industry.
Polyester fabrics are strong, flexible, and offer additional benefit of less wrinkles and shrinkage over cotton.
Polyester fabrics are light-weight, reduced-wind, drag-resistant and more resistant to tears.
-Thanks to good electrical insulating properties, high structural and dimensional stability, polyethylene terephthalate is widely used in electrical and electronics industry.
Polyethylene terephthalate is an effective polymer to replace die casts metals and thermosets in applications like: electrical encapsulation, solenoids, smart meters, photovoltaic parts, solar junction boxes, etc.
Polymer’s outstanding flow characteristics enable design freedom and miniaturization to produce high-performance parts.
-PET is successfully being used in many applications in the automotive industry.
Polyethylene terephthalate is currently being employed in the following applications: wiper arm and gear housings, headlamp retainer, engine cover, connector housings.
-Polyethylene terephthalate (PETE or PET) is the most commonly used thermoplastic polymer in the world and is better known in the textile industry by the trade name “polyester”.
Polyethylene terephthalate is a naturally transparent and semi-crystalline plastic widely used as a fiber for clothing, as an effective moisture barrier with wide applicability in bottling and packaging (known in these cases as PET or “PET resin”), and as an engineering plastic when Polyethylene terephthalate is combined with other materials like glass fiber or carbon nanotubes to significantly increase the material’s strength.
-Polyethylene terephthalate is a naturally colorless, semi-crystalline material.
Some of its most important characteristics include PETs resistance to water, PETs high strength to weight ratio, the fact that Polyethylene terephthalate is virtually shatterproof (PET won’t break like glass packaging), and its wide availability as an economic and recyclable plastic (resin identification code “1”).
-There are many different uses for PET.
One of the most common is for drink bottles, including soft drinks and more.
PET film or what is called Mylar is used for balloons, flexible food packaging, space blankets, and as a carrier for magnetic tape or backing for pressure-sensitive adhesive tape.
-In addition, Polyethylene terephthalate can be formed to make trays for frozen dinners and for other packaging trays and blisters.
If glass particles or fibers are added to the PET, Polyethylene terephthalate becomes more durable and stiffer in nature.
PET is largely used for synthetic fibers, also known as polyester.
-Because of PETs versatility, PET is used in not only the production of containers and packaging but also in the creation of polyester clothing.
-Polyethylene terephthalate is one of the most common plastics.
Polyethylene terephthalate’s used in a variety of items from water bottles and product packaging to baby wipes, clothing, bedding and mattresses.
-Making PET is an energy-intensive process.
When used in the form of polyester for textiles, Polyethylene terephthalate uses far more energy than the manufacturing of other textiles like conventional or organic hemp and cotton, but Polyethylene terephthalate’s sold less expensively.
-Many industries can benefit from the advantages of PET including food and beverage products, household chemical companies, the health and beauty industry, and personal care items.
-PET is an extremely popular option for packaging products like salad dressing, cooking oils, shampoo and conditioner, window cleaner, and even tennis balls.
-Labeled with the #1 code on or near the bottom of bottles and containers, PET is frequently used to package a range of products including beverages, peanut butter, bakery goods, produce, frozen foods, salad dressings, cosmetics, and household cleaners.
-PET is a colourless, transparent polymer that is almost unbreakable and can be recycled well.
These good properties led to broad distribution of PET as a packaging material for beverages.
By contrast with beverage cans or cartons, the transparency allows the beverage to be seen.
The unbreakable nature of PET is an advantage over glass bottles.
Moreover PET is distinctly lighter than glass.
-In the packaging sector PET is used to make films, trays and bottles.
Beverage bottles dominate production for the packaging sector.
In 2014 about 80 % of the material was used to package beverages, and almost 70 % of this for mineral water and sweet beverages.
-Food packaging (microwavable meals)
-Thin film
-Solar cells
-Thermal insulation
-Adhesive tape
-Magnetic tape
-Polyester and associated textile products
-Beverage bottles
-Food jars like peanut butter
-Salad bottles
-Cooking oil containers
-Shampoo & conditioner, soap, and other personnel care products
-Pharmaceuticals and medical supplies
-Bean bags
-Rope
-Carpet
-Pillow and sleeping bag filling
-Textile fibers such as our clothing, linens, and other fabric items
-Plastic Water Bottles
-For the manufacturing of shopping bags, water bottles, videotapes
-For manufacturing of, containers and bags
-For the manufacturing of clothes and housing material
-For manufacturing of water bottles
-For manufacturing of microwaves containers
-For manufacturing of carpets
-For the manufacturing of packaging films
-As PET is a thermoplastic, within a certain temperature band the polymer becomes extremely pliable, making it easy to mould in to shapes.
This occurs between the glass transition temperature and the melting point, which for PET are 75oC and 255oC respectively. Once cooled, PET will return to a solid form, making the plastic polymer extremely useful for drinks bottles.
PET is also almost completely impermeable.
-Polyethylene terephthalate (PET) is a thermoplastic polyester engineering resin.
When used as an injection molding compound, PET must be reinforced with glass and/or minerals.
-When PET is compounded with reinforcements, PETs strength, rigidity and heat resistance properties are dramatically enhanced.
PET resins are also noted for their excellent melt flow characteristics, close molding tolerances and high productivity from multicavity molds.
-Because PETs mechanical and electrical properties are so broad, PET is often used to replace metals in motor housings, switches, sensors and other electrical applications.
-The first picture that comes to mind when you mention PET is a plastic water bottle; however, interestingly, most PET in the world is found in clothing.
The fabric referred to as polyester is the same stuff that goes into plastic bottles.
-Polyethylene terephthalate (PET) acts as an anticorrosive coating when applied to carbon steel via the use of an industrial press.
Empirically, PET has good adhesion on these substrates in comparison to traditional organic coatings.
The following desirable properties have been observed (via the use of scanning electron microscopy) with respect to the application of PET as a corrosion prevention substance on steel substrates:
-Excellent coating layer uniformity
-Free of cracks and defects
-No susceptibility of PTE to negative effects by the deposition process
-A thin application of 65 µm is required for a high-performance coating
-No effect of PET's electrochemical behavior with respect to increased exposure time to an acidic electrolyte
-Polyethylene terephthalate which is also abbreviated as PET / PETE is mainly used to manufacture the packaging material for food products such as fruit and drinks containers.
Polyethylene terephthalate is lightweight, transparent and also available in some colour.
Polyethylene terephthalate is a member of the ester family so also called as polyester.
Polyethylene terephthalate is a recyclable thermoplastic polymer with good strength, ductility, stiffness and hardness, therefore, can be processed through vacuum forming, injection moulding, compression moulding and blow moulding.
-PET / PETE can also be recycled back to its original elements as well as into polyester fibres.
These polyester fibres are used in the manufacturing of synthetic carpets, synthetic clothing and other textile products.
PET fibres are wrinkle-free and less expensive therefore often mixed with natural fibres.
Polyethylene terephthalate is also used for the manufacture of microwavable trays and for the packaging of microwavable meals, in containers for cosmetic products and pharmaceutical products.
-Crystalline PET (40-50% crystallinity) has excellent mechanical properties and a high heat deformation temperature (comparable to PA6 and PBT), modulus and brilliance.
For this reason PET is used in the automotive and engineering polymers sector.
Using low mold temperatures, with PET it is possible to obtain transparent moldings without fillers.
PET is the most widely used polymer in the bottling industry due to PETs transparency combined with PETs mechanical and gas barrier properties.
-There are two key characteristics to PET’s ability to keep foods and beverages fresh and safe for consumption.
Unlike some other plastic resins, PET does not release harmful chemicals.
PET is also impenetrable by bacteria.
This is why PET is commonly used to make peanut butter jars, microwaveable food packs, and water- and soda-bottles, among other products.
-Food and beverage packaging is by far the most common application of PET, though it’s also used for numerous other household and industrial products.
Convenience-sized soft drinks, juices, and water are almost always stored in PET packaging.
Other applications include peanut butter or jelly jars, cooking oil bottles, or salad dressing bottles.
Non-food packaging applications include shampoo and conditioner bottles, liquid hand soap containers, and mouthwash bottles.
-Non-consumer goods applications include food processing machinery components, valve components, filler pistons, bearings, wear pads, wheels, and rollers.
PET can also be used in textiles, particularly in combination with materials such as cotton.
In addition, PET is often used for Fused Deposition Modeling (FDM) 3D-printed prototypes.
-Successfully used in the packaging for carbonated soft drinks, bottled water, milk, juice, sports and energy drinks, jars, punnets, tubs and trays for food items, bottles for household, personal care and pharmaceutical products, and sheet and film for packaging, PET is the type of plastic labeled with the # 1 code on or near the bottom of bottles and containers.
-Polyethylene terephthalate (PET) plastic is used to produce fibers and yarn, engineering plastics, photo and packing film, beverage and food containers.
-PET also forms a clear polymer so PET is also used in films such as Mylar, as well as in photographic films and transparencies.
-Polyester fibers are also used industrially in ropes and filter construction and are mixed with steel cord in the manufacture of tires.
-Polyesters also have medical applications since their strong fibers can be used to surgically repair damaged tissues.
-The everyday name depends on whether it is being used as polyester staple fibre for textile and other end uses or as material for rigid packaging, the latter being known commonly as PET.
PET is labelled with the # 1 resin identification code.
POLYETHYLENE TEREPHTHALATE PROPERTIES:
*Crystal clear polymer:
PET is a crystal clear polymer with good purity and healthy.
You must have seen the sparkling PET bottles with brilliant glass-clear presentation attract us.
*Purity:
The products of PET taste good and comply with international food contact regulations.
*Safe:
The objects made from PET like bottles are tough and virtually unbreakable therefore can be easily used for storage and transportation.
This polymer has a high impact and tensile strength that makes PET ideal for carbonated products.
*Good barrier:
PET products have low permeability to oxygen, carbon dioxide and water, therefore, PET maintains the integrity of products with good shelf life.
*Lightweight:
The lightweight of PET products reduce the shipping costs compared to glass products.
*No Leakage and damage:
Due to the absence of weld line in the base, PET bottles are free from leakage and damage.
*Recyclable:
PET polymer is recyclable and can be reshaped in different shapes.
*Good resistance power:
PET products have good resistance against different chemicals such as acids, bases, etc.
WHT IS POLYETHYLENE TEREPHTHALATE (PETE or PET) USED SO OFTEN?
PET is unique in that Polyethylene terephthalate is virtually shatterproof, has an extremely high strength to weight ratio and does not react to food and water.
The combination of these material properties in addition to PETs wide availability and low price make Polyethylene terephthalate a nearly unbeatable solution for consumable product packaging.
Polyester for fabrics is strong, flexible, and when combined with materials like cotton can reduce wrinkling, shrinking, and makes the fabric more resistant to tears.
WHAT ARE THE DIFFERENT TYPES of POLYETHYLENE TEREPHTHALATE?
Polyethylene terephthalate is available both as a homopolymer and also as a product that has been modified by copolymers. When Polyethylene terephthalate is used for textiles PET is called “polyester.”
When Polyethylene terephthalate is used for food and beverage packaging Polyethylene terephthalate is generally called “PET” or “PET resin.”
A now obsolete version of the product was known as “PET-P.”
Polyethylene terephthalate is most commonly used, however in the form of a fabric - one of the most famous of which is called "polyester."
HOW IS POLYETHYLENE TEREPHTHALATE MADE?
Polyethylene terephthalate, like other plastics, typically starts with the distillation of hydrocarbon fuels into lighter groups called “fractions” some of which are combined with other catalysts to produce plastics (typically via polymerization or polycondensation).
In the case of PET, the hydrocarbon ethylene glycol is combined with terephthalic acid to produce the material.
PET is made from terephthalic acid (a dicarboxylic acid) and ethylene glycol (a dialcohol).
Both substances combine to form long polymer chains. Water results as a product of reaction.
The polymerisation reaction proceeds in several stages.
First a „pre-polymer“ is produced, which is then polymerised further in the melt to longer chains.
Like most polymerisation reactions, this reaction too needs a catalyst.
For use in PET bottles, in a further production stage the polymer is then heated in granular form for several hours.
This results in a polyester polymer which displays the right properties for producing PET bottles.
PRODUCTION of POLYETHYLENE TEREPHTHALATE:
PET bottles are produced in a two-stage process.
The PET granules are melted at about 280 °C and processed to create a preform.
This preform already possesses the later closure thread, but is small and, as already mentioned, can be transported well. Shortly before the filling process the preform is heated up again to about 120 °C and blow-moulded into its fi nal bottle form.
In the case of disposable PET bottles this step is performed directly at the fi lling plant.
Returnable PET bottles are delivered to the filling plant as fi nished bottles.
The PET material is partly crystallised by the „stretch blow moulding process“.
Although a production process with partially crystalline sectors reduces transparency a little, it improves the stability of the PET bottles and the barrier against oxygen and carbonic acid.
Completely crystalline PET is opaque and is used, for example, for microwave trays.
Polyethylene terephthalate is produced from ethylene glycol and dimethyl terephthalate (DMT) (C6H4(CO2CH3)2) or terephthalic acid.
The former is a transesterification reaction, whereas the latter is an esterification reaction.
*Dimethyl terephthalate process (DMT):
In dimethyl terephthalate(DMT) process, this compound and excess ethylene glycol are reacted in the melt at 150–200 °C with a basic catalyst.
Methanol (CH3OH) is removed by distillation to drive the reaction forward.
Excess ethylene glycol is distilled off at higher temperature with the aid of vacuum.
The second transesterification step proceeds at 270–280 °C, with continuous distillation of ethylene glycol as well.
*Terephthalic acid process:
In the terephthalic acid process, esterification of ethylene glycol and terephthalic acid is conducted directly at moderate pressure (2.7–5.5 bar) and high temperature (220–260 °C).
Water is eliminated in the reaction, and it is also continuously removed by distillation.
WHAT ARE THE CHARACTERISTICS of POLYETHYLENE TEREPHTHALATE (PETE or PET)?
Some of the most significant properties of Polyethylene terephthalate (PETE or PET) are:
*Chemical Resistance: PET does not react with water or food which is one of the reasons PET is used for consumable packaging. *Strength to Weight Ratio: PET is very strong for its lightweight.
*Shatterproof: PET will not break or fracture.
This makes it a great replacement for glass as a container.
*Transmissivity: Polyethylene terephthalate (PETE or PET) is naturally transparent.
That said, if high transmissivity is desired then plastics like Acrylic or Polycarbonate may be better choices.
Polyethylene terephthalate is generally “thermoplastic” (as opposed to “thermoset”) material which has to do with the way the plastic responds to heat.
That said, some variants of Polyethylene terephthalate (such as certain types of polyester) are thermoset.
Thermoplastic materials become liquid at their melting point (roughly 260 degrees Celsius in the case of PET).
A major useful attribute about thermoplastics is that they can be heated to their melting point, cooled, and reheated again without significant degradation.
Instead of burning, thermoplastics like polypropylene liquefy, which allows them to be easily injection molded and then subsequently recycled.
By contrast, thermoset plastics can only be heated once (typically during the injection molding process).
The first heating causes thermoset materials to set (similar to a 2-part epoxy) resulting in a chemical change that cannot be reversed.
If you tried to heat a thermoset plastic to a high temperature a second time it would simply burn.
This characteristic makes thermoset materials poor candidates for recycling.
FULLY RECYCLABLE of POLYETHYLENE TEREPHTHALATE:
PET is completely recyclable.
PET can easily be identified by the #1 in the triangular "chasing arrows" code, which is usually found molded into the bottom or side of the container.
No other plastic carries the #1 code.
PET can be commercially recycled by thorough washing and re-melting, or by chemically breaking Polyethylene terephthalate down to Polyethylene terephthalate's component materials to make new PET resin.
Products commonly made from recycled PET include new PET bottles and jars, carpet, clothing, industrial strapping, rope, automotive parts, fiberfill for winter jackets and sleeping bags, construction materials, and protective packaging.
Although recycling is the most environmentally responsible and efficient re-use of resources, PET bottles and containers that find their way to the landfill pose no risk of harm or leaching.
Since the polymer is inert, Polyethylene terephthalate is resistant to attack by micro-organisms, and won't biologically degrade.
PET also takes up relatively little landfill space since Polyethylene terephthalate is easily crushed flat.
Recycled PET can be used in a number of different things, including polyester fibers for carpeting, parts for cars, fiberfill for coats and sleeping bags, shoes, luggage, t-shirts, and more.
The way to tell if you are dealing with PET plastic is looking for the recycling symbol with the number "1" inside of it.
The easiest way to recycle PET is to chop bottles (and any other stuff made of PET) into small flakes and pellets.
This waste product then becomes quite valuable, because PET can be melted down and used to create new containers.
But there’s also a chemical way to recycle PET.
Chemists know how to break down the ester bonds that hold PET together and obtain the monomers again.
This process involves a couple of steps.
First comes something called partial glycolyiss, where the polymer is treated with ethylene glycol.
This breaks the long polymer chains down into shorter chains, called oligomers, which melt at cooler temperatures and thus can be filtered to remove any impurities.
Then, once the material has been purified, it’s completely broken down into the monomers , which get purified by distillation.
Once the monomers are obtained, they can be used to produce new, shiny PET again.
And then there’s yet another way to recycle PET, and PET goes back to Whinfield’s original aim – making fibres.
Used bottles can be turned into fibres, which are then used to make fabrics.
As a raw material, PET is recognized around the world as a strong, safe, non-toxic, lightweight, and flexible material that’s 100% recyclable.
In fact, PET’s the most widely recycled plastic in the world!
Each PET container is clearly marked with the recycle No. 1 code, so consumers are immediately informed of its recyclability.
RPET is employed for new products such as:
-Polyester carpet fiber
-Fabric for T-shirts
-Long underwear
-Athletic shoes
-Luggage, upholstery
-Sweaters and fiberfill for sleeping bags and winter coats
-Industrial strapping
-Sheet and film
-Automotive parts
-New PET containers
The use of recycled PET in place of virgin resin typically results in reduced energy consumption, lower cost, and reduced environmental impact.
Thermoplastics, such as PET, are generally easy to recycle because the polymer chain breaks down at a relatively low temperature, and so there is no degradation of the polymer chain during the recycling process.
This allows PET to be recycled a large number of times before it becomes unusable, though contamination can reduce the number of ‘closed loop’ cycles that PET can go through.
The exact recycling process will vary from plant to plant, but in general the following steps are taken:
Bottles are sorted by hand and unwanted materials are removed so that only bottles are left.
Alternatively, the bottles can be sorted using an automated system.
The bottles are then cleaned inside and out to remove any residual liquid or dirt to prevent contamination.
The bottles can then be sorted infrared radiation techniques, to determine which polymers are present.
If bottles are also sorted by colour, traditionally blue, natural, green and mixed, it can add further value to the plastic.
Next the bottles are shredded into flakes, which are then washed again.
Alternatively, the shredding step can be skipped and the bottle is melted and reformed into a different shape.
The shredded plastic is then melted to produce plastic granulates, or pellets.
RECYCLING PROCESS of PET:
After the sorting process, the PET material is ground into particles known as “flakes.”
Flake purity is central to preserving the value of the reclaimed plastic.
Further separation techniques involve washing and air classification as well as water baths, where material either sinks or floats, which helps separate residual foreign materials.
Washing can be undertaken at standard or elevated heat levels.
The use of disinfectants and detergents aids in achieving a complete cleaning.
After the completion of grinding, washing and separation, the material is rinsed to eliminate any remaining contaminants or cleaning agents.
The recycled PET is then dried before reintroduction as a manufacturing material or before further processing.
Melt filtering can further purify material through the removal of any non-melting contaminants that may have survived earlier steps.
Extruded material passes through a series of screens to form pellets while non-melted particulate is blocked.
Pelletized plastic provides a uniform-sized material that can be reintroduced into the manufacturing process.
WHY CHOOSE POLYETHYLENE TEREPHTHALATE?
Strong, transparent, lightweight, and environmentally friendly, PET’s difficult to beat PET when PET comes to packaging and other applications that require a strong, rigid, and lightweight material.
PET can safely interact with food and beverages without letting in outside air, chemicals, or liquid, and PET maintains all of these properties at a fairly wide range of temperatures and conditions.
In addition, PET can be manipulated or combined with other materials to form a thin film or flexible polyester textiles.
PET can replace die-cast metals and thermosets in electrical encapsulation, smart meters, photovoltaic parts, and more.
PET is also commonly used in the automotive industry — wiper arms, gear housings, engine covers, and more are all made from PET.
What’s more, PET isn’t just versatile in terms of applications.
PET’s also versatile when PET comes to manufacturing methods.
PET can be easily processed by injection molding, extrusion, blow molding, thermoforming, and 3D printing.
SUSTAINABLE of POLYETHYLENE TEREPHTHALATE:
PET is a very energy-efficient packaging material.
Although its raw materials are derived from crude oil and natural gas, Polyethylene terephthalate enjoys a very favorable sustainability profile in comparison to glass, aluminum and other container materials.
Polyethylene terephthalate's sustainability jumps even higher when recycling is introduced, since approximately 40% of PET's energy use is attributable to PETs "resource energy" - the energy inherently trapped in PETs raw materials that can be recaptured and reused through recycling.
The high strength of PET in comparison to PETs light weight is a major key to PETs energy efficiency, allowing for more product to be delivered in less packaging and using less fuel for transport.
Ongoing advances in light-weighting technology continue to improve PETs energy efficiency even further.
Life cycle studies of PET have consistently confirmed the environmental benefits of PET as a packaging material.
In the 60 years since PET was first synthesized, Polyethylene terephthalate has become one of the world's most widely used, versatile and trusted materials.
PHYSICAL PROPERTIES of POLYETHYLENE TEREPHTHALATE:
Sailcloth is typically made from PET fibers also known as polyester; colorful lightweight spinnakers are usually made of nylon.
PET in its natural state is a colorless, semi-crystalline resin.
Based on how Polyethylene terephthalate is processed, PET can be semi-rigid to rigid, and Polyethylene terephthalate is very lightweight.
Polyethylene terephthalate makes a good gas and fair moisture barrier, as well as a good barrier to alcohol (requires additional "barrier" treatment) and solvents.
Polyethylene terephthalate is strong and impact-resistant.
PET becomes white when exposed to chloroform and also certain other chemicals such as toluene.
About 60% crystallization is the upper limit for commercial products, with the exception of polyester fibers.
Clear products can be produced by rapidly cooling molten polymer below Tg glass transition temperature to form an amorphous solid.
Like glass, amorphous PET forms when its molecules are not given enough time to arrange themselves in an orderly, crystalline fashion as the melt is cooled.
At room temperature the molecules are frozen in place, but, if enough heat energy is put back into them by heating above Tg, they begin to move again, allowing crystals to nucleate and grow.
This procedure is known as solid-state crystallization.
When allowed to cool slowly, the molten polymer forms a more crystalline material.
This material has spherulites containing many small crystallites when crystallized from an amorphous solid, rather than forming one large single crystal.
Light tends to scatter as it crosses the boundaries between crystallites and the amorphous regions between them.
This scattering means that crystalline PET is opaque and white in most cases.
Fiber drawing is among the few industrial processes that produce a nearly single-crystal product.
CHEMICAL PROPERTIES of POLYETHYLENE TEREPHTHALATE:
This plastic is a thermoplastic resin of the polyester family and is commonly used in many different products, including synthetic fibers.
It can exist in both a transparent and a semi-crystalline polymer, depending upon the processing and thermal history. Polyethylene terephthalate is a polymer that is formed by combining two monomers: modified ethylene glycol and purified terephthalic acid.
PET can be modified with additional polymers as well, making it acceptable and usable for other uses.
INTRINSIC VISCOSITY of POLYETHYLENE TEREPHTHALATE:
One of the most important characteristics of PET is referred to as intrinsic viscosity (IV).
The intrinsic viscosity of the material, found by extrapolating to zero concentration of relative viscosity to concentration which is measured in deciliters per gram (dℓ/g).
Intrinsic viscosity is dependent upon the length of its polymer chains but has no units due to being extrapolated to zero concentration.
The longer the polymer chains the more entanglements between chains and therefore the higher the viscosity.
The average chain length of a particular batch of resin can be controlled during polycondensation.
The intrinsic viscosity range of PET:
*Fiber grade:
0.40–0.70, textile
0.72–0.98, technical, tire cord
*Film grade:
0.60–0.70, biaxially oriented PET film
0.70–1.00, sheet grade for thermoforming
*Bottle grade:
0.70–0.78, water bottles (flat)
0.78–0.85, carbonated soft drink grade
*Monofilament, engineering plastic:
1.00–2.00
ADVANTAGES of POLYETHYLENE TEREPHTHALATE:
PET offers several different advantages.
PET can be found in many different forms, from semi-rigid to rigid.
This is largely dependent upon PETs thickness.
Polyethylene terephthalate is a lightweight plastic that can be made into a number of different products.
Polyethylene terephthalate is very strong and has impact-resistant properties as well.
As far as color, Polyethylene terephthalate is largely colorless and transparent, although color can be added, depending upon the product that Polyethylene terephthalate is being used for.
These advantages make PET one of the most common types of plastic that are found today.
*Crystal Clear Appearance:
The appearance of a bottle made from PET is as clear as its glass counterpart.
*Pure:
PET complies with international food contact regulations.
This not only ensures that products are safe, but the products inside PET containers also taste great
*Safe:
Although PET may not look like it, PET bottles are tough and virtually indestructible.
This makes PET products a great choice from production and storage, all the way through transport.
If a PET bottle does break, PET splits instead of shattering, unlike many other bottles.
*Good Barrier:
Many manufacturers prefer to use PET in their products because PET allows for low permeability of oxygen, carbon dioxide, and water.
These characteristics help protect and maintain the integrity of each product, and assists in creating a longer shelf life.
*Lightweight:
MJS Packaging has seen many customers make the switch from glass to plastic in order to reduce weight costs.
This decision can result in a reduction of shipping costs of approximately 30%.
PET bottles that are high strength and low weight can be stacked as high as glass.
*Great Design Flexibility:
PET is suitable for containers of all shapes, sizes, neck finishes, designs and colors.
The possibilities are virtually endless.
*Recyclable:
As noted above, PET is the most widely recycled material across the globe.
Used PET containers can be washed, granulated into flakes, and reshaped as PET bottles.
They can also be used for strapping, carpeting, and fiber filling.
PET contains no toxic substances.
When burned, PET produces carbon dioxide gas and water, leaving no toxic residues.
DRYING of POLYETHYLENE TEREPHTHALATE:
PET is hygroscopic, meaning that it absorbs water from its surroundings.
However, when this "damp" PET is then heated, the water hydrolyzes the PET, decreasing PETs resilience.
Thus, before the resin can be processed in a molding machine, PET must be dried.
Drying is achieved through the use of a desiccant or dryers before the PET is fed into the processing equipment.
Inside the dryer, hot dry air is pumped into the bottom of the hopper containing the resin so that PET flows up through the pellets, removing moisture on its way.
The hot wet air leaves the top of the hopper and is first run through an after-cooler, because it is easier to remove moisture from cold air than hot air.
The resulting cool wet air is then passed through a desiccant bed.
Finally, the cool dry air leaving the desiccant bed is re-heated in a process heater and sent back through the same processes in a closed loop.
Typically, residual moisture levels in the resin must be less than 50 parts per million (parts of water per million parts of resin, by weight) before processing.
Dryer residence time should not be shorter than about four hours.
This is because drying the material in less than 4 hours would require a temperature above 160 °C, at which level hydrolysis would begin inside the pellets before they could be dried out.
PET can also be dried in compressed air resin dryers.
Compressed air dryers do not reuse drying air.
Dry, heated compressed air is circulated through the PET pellets as in the desiccant dryer, then released to the atmosphere.
COPOLYMERS of POLYETHYLENE TEREPHTHALATE:
In addition to pure (homopolymer) PET, PET modified by copolymerization is also available.
In some cases, the modified properties of a copolymer are more desirable for a particular application.
For example, cyclohexanedimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol.
Since this building block is much larger (six additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighboring chains the way an ethylene glycol unit would.
This interferes with crystallization and lowers the polymer's melting temperature.
In general, such PET is known as PETG or PET-G (polyethylene terephthalate glycol-modified).
PETG is a clear amorphous thermoplastic that can be injection-molded, sheet-extruded or extruded as filament for 3D printing. PETG can be colored during processing.
Another common modifier is isophthalic acid, replacing some of the 1,4-(para-) linked terephthalate units.
The 1,2-(ortho-) or 1,3-(meta-) linkage produces an angle in the chain, which also disturbs crystallinity.
Such copolymers are advantageous for certain molding applications, such as thermoforming, which is used for example to make tray or blister packaging from co-PET film, or amorphous PET sheet (A-PET/PETA) or PETG sheet.
On the other hand, crystallization is important in other applications where mechanical and dimensional stability are important, such as seat belts.
For PET bottles, the use of small amounts of isophthalic acid, CHDM, diethylene glycol (DEG) or other comonomers can be useful: if only small amounts of comonomers are used, crystallization is slowed but not prevented entirely.
As a result, bottles are obtainable via stretch blow molding ("SBM"), which are both clear and crystalline enough to be an adequate barrier to aromas and even gases, such as carbon dioxide in carbonated beverages.
PHYSICAL and CHEMICAL PROPERTIES of POLYETHYLENE TEREPHTHALATE:
Appearance Form: solid
Formula Weight: 228.19868
Odour: No data available
Odour Threshold: No data available
pH: No data available
Melting point:250-255 °C
Boiling point:>170 °C(Press: 10 Torr)
Density 1.68 g/mL at 25 °C
Form: pellets
Color: black
Flash point: No data available
Evaporation rate: No data available
Flammability (solid, gas): No data available
Upper/lower flammability or explosive limits: No data available
Vapour pressure: No data available
Vapour density: No data available
Relative density: 1,375 g/cm3
Water solubility: No data available
Partition coefficient: n-octanol/water: No data available
Auto-ignition temperature: No data available
Decomposition temperature: No data available
Viscosity: No data available
Explosive properties: No data available
Oxidizing properties: No data available
Water Absorption: 0.0500 - 0.800 %
Moisture Absorption at Equilibrium: 0.200 - 0.600 %
Water Absorption at Saturation: 0.400 - 0.700 %
Particle Size: 2500 - 3500 µm
Water Vapor Transmission: 0.490 - 6.00 g/m²/day Count:6
Oxygen Transmission: 5.10 - 23.0 cc-mm/m²-24hr-atm
Oxygen Transmission Rate: 2.00 - 20.0 cc/m²/day
Viscosity Test: 62.0 - 86.0 cm³/g
Maximum Moisture Content: 0.350 - 0.400
Thickness: 100 - 1200 microns
Linear Mold Shrinkage: 0.00100 - 0.0200 cm/cm
Linear Mold Shrinkage, Transverse: 0.00100 - 0.0110 cm/cm
Melt Flow: 3.50 - 65.0 g/10 min
Mechanical Properties
Hardness, Rockwell M: 80.0 - 96.0
Hardness, Rockwell R: 105 - 125
Hardness, Shore D: 71.4 - 87.0
Ball Indentation Hardness: 117 - 170 MPa
Tensile Strength, Ultimate: 3.00 - 90.0 MPa
Film Tensile Strength at Yield, MD: 55.0 - 260 MPa
Film Tensile Strength at Yield, TD: 53.0 - 265 MPa
Tensile Strength, Yield: 5.52 - 90.0 MPa
Film Elongation at Break, MD: 40.0 - 600 %
Film Elongation at Break, TD: 30.0 - 600 %
Film Elongation at Yield, MD: 4.00 - 6.00 %
Film Elongation at Yield, TD: 4.00 - 6.00 %
Elongation at Break: 4.00 - 600 %
Elongation at Yield: 3.50 - 8.00 %
Modulus of Elasticity: 0.140 - 5.20 GPa
Flexural Yield Strength: 55.3 - 121 MPa
Flexural Modulus: 0.138 - 3.31 GPa
Compressive Yield Strength: 2.30 - 103 MPa
Compressive Modulus: 0.0900 - 2.80 GPa
Shear Modulus: 0.0350 - 0.0500 GPa
Shear Strength: 1.20 - 58.6 MPa
Secant Modulus: 0.00100 - 2.10 GPa
Izod Impact, Notched: 0.139 - 100 J/cm
FIRST AID MEASURES of POLYETHYLENE TEREPHTHALATE:
-Description of first aid measures:
*If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
*In case of skin contact:
Wash off with soap and plenty of water.
*In case of eye contact:
Flush eyes with water as a precaution.
*If swallowed:
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
ACCIDENTAL RELEASE MEASURES of POLYETHYLENE TEREPHTHALATE:
-Environmental precautions:
No special environmental precautions required.
-Methods and materials for containment and cleaning up:
Sweep up and shovel.
Keep in suitable, closed containers for disposal.
FIREFIGHTING MEASURES of POLYETHYLENE TEREPHTHALATE:
-Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
-Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
-Further information: No data available
EXPOSURE CONTROLS/PERSONAL PROTECTION of POLYETHYLENE TEREPHTHALATE:
-Control parameters:
Components with workplace control parameters:
-Exposure controls:
*Appropriate engineering controls:
General industrial hygiene practice.
Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
*Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
*Respiratory protection:
Respiratory protection is not required.
Where protection from nuisance levels of dusts are desired, use type N95 (US) or type P1 (EN 143) dust masks.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
*Control of environmental exposure:
No special environmental precautions required.
HANDLING and STORAGE of POLYETHYLENE TEREPHTHALATE:
-Precautions for safe handling:
-Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Store in cool place
STABILITY and REACTIVITY of POLYETHYLENE TEREPHTHALATE:
-Reactivity: No data available
-Chemical stability:
Stable under recommended storage conditions.
-Possibility of hazardous reactions: No data available
-Conditions to avoid: No data available
SYNONYMS:
Poly(ethylene terephthalate)
SCHEMBL9918169
DTXSID10872790
2-methoxyethyl 4-acetylbenzoate
Mylar
Terom
Vituf
Estar
klt40
mylara
mylarc
mylart
Terfan
Tergal
