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Encyclopedia > Polyethylene terephthalate
PET
Molecular formula C10H8O4
Density 1370 kg/m3
Young's modulus(E) 2800–3100 MPa
Tensile strengtht) 55–75 MPa
Elastic limit 50–150%
notch test 3.6 kJ/m2
Glass temperature 75 °C
melting point 260 °C
Vicat B 170 °C
Thermal conductivity 0.24 W/(m·K)
linear expansion coefficient (α) 7×10−5/K
Specific heat (c) 1.0 kJ/(kg·K)
Water absorption (ASTM) 0.16
Price 0.5–1.25 €/kg
source: A.K. vam der Vegt & L.E. Govaert, Polymeren, van keten tot kunstof, ISBN 90-407-2388-5

Polyethylene terephthalate (aka 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 with glass fiber. It is one of the most important raw materials used in man-made fibers. Look up Peter, peter in Wiktionary, the free dictionary. ... Pete may refer to: In athletics: The Petersen Events Center, an athletics complex and basketball arena on the campus of the University of Pittsburgh Pete Rose, an American former player and manager in Major League Baseball. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... For other uses, see Density (disambiguation). ... Kilogram per cubic metre is the SI measure of density and is represented as kg/m³, where kg stands for kilogram and m³ stands for cubic metre. ... In solid mechanics, Youngs modulus (E) is a measure of the stiffness of a given material. ... For other uses, see Pascal. ... Tensile strength isthe measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. ... A kilojoule (abbreviation: kJ) is a unit of energy equal to 1000 joules. ... This article is about the unit of length. ... The glass transition temperature is the temperature below which the physical properties of amorphous materials vary in a manner similar to those of a solid phase (glassy state), and above which amorphous materials behave like liquids (rubbery state). ... The degree Celsius (symbol: °C) is an SI derived unit of temperature. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... This article needs to be wikified. ... For other uses, see Kelvin (disambiguation). ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the temperature of a unit quantity of a substance by a certain temperature interval. ... Kg redirects here. ... For other uses, see Plastic (disambiguation). ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... SEM picture of a bend in a high surface area polyester fiber with a seven-lobed cross section Polyester (aka Terylene) is a category of polymers which contain the ester functional group in their main chain. ... Synthetic fibres are the result of extensive research by scientists to increase and improve upon the supply of naturally occurring animal and plant fibres that have been used in making cloth and rope. ... Look up container in Wiktionary, the free dictionary. ... This article is about the type of fabric. ...


Depending on its processing and thermal history, it may exist both as an amorphous (transparent) and as a semi-crystalline (opaque and white) material. Its monomer can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct, or the transesterification reaction between ethylene glycol and dimethyl terephthalate with methanol as a byproduct. Polymerization is through a polycondensation reaction of the monomers (done immediately after esterification/transesterification) with ethylene glycol as the byproduct (the ethylene glycol is recycled in production). Wax and paraffin are amorphous. ... For other uses, see Crystal (disambiguation). ... Esterification is the general name for a chemical reaction in which two chemicals (typically an alcohol and an acid) form an ester as the reaction product. ... Terephthalic acid is one isomer of the three phthalic acids. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ... In organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ... Dimethyl terephthalate is an organic chemical used in the production of polyesters, including polyethylene terephthalate. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ...


The majority of the world's PET production is for synthetic fibers (in excess of 60%) with bottle production accounting for around 30% of global demand. In discussing textile applications, PET is generally referred to as simply "polyester" while "PET" is used most often to refer to packaging applications.


It is manufactured under trade names Arnite, Impet and Rynite, Ertalyte, Hostaphan, Melinex and Mylar films, and Dacron, Diolen, Terylene & Trevira fibers. [1] Biaxially-oriented polyethylene terephthalate (boPET) polyester film is used for its high tensile strength, chemical and dimensional stability, transparency, gas and aroma barrier properties and electrical insulation. ...

Chemical structure of polyethylene terephthalate

Contents

Image File history File links Download high resolution version (2244x945, 12 KB) Summary Structure of PET (polyethylene terephthalate). ... Image File history File links Download high resolution version (2244x945, 12 KB) Summary Structure of PET (polyethylene terephthalate). ...

Uses

PET can be semi-rigid to rigid, depending on its thickness, and is very lightweight. It makes a good gas and fair moisture barrier, as well as a good barrier to alcohol (requires additional "Barrier" treatment) and solvents. It is strong and impact-resistant. It is naturally colorless with high transparency. Download high resolution version (202x660, 33 KB) File links The following pages link to this file: Bottle Polyethylene terephthalate Lilt Categories: GFDL images ... Download high resolution version (202x660, 33 KB) File links The following pages link to this file: Bottle Polyethylene terephthalate Lilt Categories: GFDL images ... A soft drink is a drink that contains no alcohol. ... Composite body, painted, and glazed bottle. ... This article does not cite any references or sources. ... For other uses, see Solvent (disambiguation). ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ...


When produced as a thin film (often known by the tradename Mylar), PET is often coated with aluminium to reduce its permeability, and to make it reflective and opaque. PET bottles are excellent barrier materials and are widely used for soft drinks, (see carbonation). PET or Dacron is also used as a thermal insulation layer on the outside of the International Space Station as seen in an episode of Modern Marvels "Sub Zero". For certain specialty bottles, PET sandwiches an additional polyvinyl alcohol to further reduce its oxygen permeability. Mylar is a trade name of DuPont Teijin Films of Hopewell, VA, United States, for biaxially-oriented polyethylene terephthalate (BOPET) polyester film used for its high tensile strength, chemical and dimensional stability, transparency, and electrical insulation. ... Sputtering is a physical vapor deposition, PVD process whereby atoms in a solid target material are ejected into the gas phase due to bombardment of the material by energetic ions. ... Aluminum redirects here. ... // Photo of Personal Care Plastic Bottles from www. ... A soft drink is a drink that contains no alcohol. ... For the chemical reaction forming calcium carbonate, see carbonatation. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... ISS redirects here. ... Bottles is a New Zealand drinking game, commonly practiced by students. ... Chemical structure of polyvinyl alcohol Polyvinyl alcohol (PVOH, PVA, or PVAL) is a water-soluble synthetic polymer. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colourless (gas) colourless (liquid) Standard atomic weight 15. ...


When filled with glass particles or fibers, it becomes significantly stiffer and more durable. This glass-filled plastic, in a semi-crystalline formulation, is sold under the tradename Rynite, Arnite, Hostadur& Crastin. This article is about the material. ... Aggregate is the component of a composite material used to resist compressive stress. ... Fibre reinforced plastic (FRP) is a composite material comprising a polymer matrix reinforced with fibres usually of glass, carbon, or aramid and is commonly used in aerospace, automotive and marine industries. ... In solid mechanics, Youngs modulus (E) is a measure of the stiffness of a given material. ...

Sails are usually made of Dacron, a brand of PET fiber; colorful lightweight spinnakers are usually made of nylon.

While all thermoplastics are technically recyclable, PET bottle recycling is more practical than many other plastic applications. The primary reason is that plastic carbonated soft drink bottles and water bottles are almost exclusively PET which makes them more easily identifiable in a recycle stream. PET has a resin identification code of 1. PET, as with many plastics, is also an excellent candidate for thermal recycling (incineration) as it is composed of carbon, hydrogen and oxygen with only trace amounts of catalyst elements (no sulphur) and has the energy content of soft coal. Image File history File links Resin-identification-code-1-PETE.svg‎ Self made from PNG. File historyClick on a date/time to view the file as it appeared at that time. ... ImageMetadata File history File links Download high resolution version (900x1260, 116 KB) Summary Photo by Paul Nelson Thistle # 3922, Terry Lettenmaier, skipper, sailing downwind at the Thistle Class Association Yale Lake Regatta, July 2004, near Cougar, Washington. ... ImageMetadata File history File links Download high resolution version (900x1260, 116 KB) Summary Photo by Paul Nelson Thistle # 3922, Terry Lettenmaier, skipper, sailing downwind at the Thistle Class Association Yale Lake Regatta, July 2004, near Cougar, Washington. ... A gaff-rigged cutter flying a mainsail, staysail and genoa jib For other uses, see Sail (disambiguation). ... For other uses, see Spinnaker (disambiguation). ... For other uses of this word, see nylon (disambiguation). ... The international recycling symbol. ... A 1. ... Sorted household plastic waiting to be hauled away for reprocessing. ...


One of the uses for a recycled PET bottle is for the manufacture of polar fleece material. Polar fleece, more often called just fleece, is a soft napped insulating synthetic wool fabric made from PET or other synthetic fibers. ...


PET was patented in 1941 by the Calico Printers' Association of Manchester. The PET bottle was patented in 1973. For other uses, see 1941 (disambiguation). ... This article is about the City of Manchester in England. ... For the song by James Blunt, see 1973 (song). ...


Intrinsic viscosity

One of the most important characteristics of PET is referred to as I.V. (intrinsic viscosity). Intrinsic viscosity is a measure of a solutes contribution to the viscosity of a solution. ...


The I.V. of the material, measured in deciliters per gram (dl/g) is dependent upon the length of its polymer chains. The longer the chains, the stiffer the material, and therefore the higher the I.V. The average chain length of a particular batch of resin can be controlled during polymerization. A decilitre (or deciliter), abbreviated dL or dl, is one tenth of a litre, or 1×10−4 m3, or 100 millilitre. ... An example of alkene polymerisation, in which each Styrene monomer units double bond reforms as a single bond with another styrene monomer and forms polystyrene. ...


An I.V. of about:

0.60 dl/g: Would be appropriate for fibre
0.65 dl/g: Film
0.76-0.84 dl/g: Bottles
0.85 dl/g: Tyre cord

For the meaning of fiber in nutrition, see dietary fiber. ... Firestone tire This article is about pneumatic tires. ...

Drying

PET is hygroscopic, meaning that it naturally absorbs water from its surroundings. However, when this 'damp' PET is then heated a chemical reaction known as hydrolysis takes place between the water and the PET which reduces its molecular weight (IV) and its physical properties. This means that before the resin can be processed in a molding machine, as much moisture as possible must be removed from the resin. This is achieved through the use of a desiccant or dryers before the PET is fed into the processing equipment. A hygroscopic substance is a substance that absorbs water readily from its surroundings. ... Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water. ... A dessicant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container. ...


Inside the dryer, hot dry air is pumped into the bottom of the hopper containing the resin so that it 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 40 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. A dessicant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container. ... Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water. ...


Copolymers

In addition to pure (homopolymer) PET, PET modified by copolymerization is also available. A homopolymer is a polymer which is formed from only one type of monomer. ... A heteropolymer, also called a copolymer, is a polymer formed when two different types of monomer are linked in the same polymer chain. ...


In some cases, the modified properties of copolymer are more desirable for a particular application. For example, cyclohexane dimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol. Since this building block is much larger (6 additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighbouring chains the way an ethylene glycol unit would. This interferes with crystallization and lowers the polymer's melting temperature. Such PET is generally known as PETG (EastmanChemical and SKchemicals are the only two manufacturers). Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...

Replacing terephthalic acid (right) with isophthalic acid (center) creates a kink in the PET chain, interfering with crystallization and lowering the polymer's melting point.

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. Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Frost crystallization on a shrub. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... Terephthalic acid is one isomer of the three phthalic acids. ... Look up meta- in Wiktionary, the free dictionary. ...


Such copolymers are advantageous for certain moulding applications, such as thermoforming, which is used for example to make tray or blister packagings from PETG film, 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 CHDM 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. A vacuum/pressure assist thermoforming machine with molds visible in the lower right. ... Arla Plast AB , headquartered in Sweden is one of Europes leading suppliers of solid extruded thermoplastic sheet. ... This article is about the safety device. ... hi meBlow molding or blow moulding (see spelling differences) is a manufacturing process by which hollow plastic parts are formed. ...


Crystals

Crystallization occurs when polymer chains fold up on themselves in a repeating, symmetrical pattern. Long polymer chains tend to become entangled on themselves, which prevents full crystallization in all but the most carefully controlled circumstances. PET is no exception to this rule; 60% crystallization is the upper limit for commercial products, with the exception of polyester fibers. For other uses, see Crystal (disambiguation). ...


PET in its natural state is a crystalline resin. Clear products can be produced by rapidly cooling molten polymer to form an amorphous solid. Like glass, amorphous PET forms when its molecules are not given enough time to arrange themselves in an orderly 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, they begin to move again, allowing crystals to nucleate and grow. This procedure is known as solid-state crystallization. Wax and paraffin are amorphous. ... This article is about the material. ... Bubbles in a soft drink each nucleate independently, responding to a decrease in pressure. ...


Like most materials, PET tends to produce 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 produces a nearly single-crystal product. A crystallite is a domain of solid-state matter that has the same structure as a single crystal. ... Cold drawing is a process, for example used in cable core production. ...


Degradation

PET is subject to various types of degradations during processing. The main degradations that can occur are hydrolytic, thermal and probably most important thermal oxidation. When PET degrades, several things happen: discolouration, chain scissions resulting in reduced molecular weight, formation of acetaldehyde and cross-links ("gel" or "fish-eye" formation). Discolouration is due to the formation of various cromophoric systems following prolonged thermal treatment at elevated temperatures. This becomes a problem when the optical requirements of the polymer are very high like for example in packaging applications. Acetaldehyde is normally a colourless gas with a fruity smell. It forms naturally in fruit, but it can cause an off-taste in bottled water. Acetaldehyde forms in PET through the "abuse" of the material. High temperatures (PET decomposes above 300 °C or 570 °F), high pressures, extruder speeds (excessive shear flow raises temperature) and long barrel residence times all contribute to the production of acetaldehyde. When acetaldehyde is produced, some of it remains dissolved in the walls of a container and then diffuses into the product stored inside, altering the taste and aroma. This is not such a problem for non-consumables such as shampoo, for fruit juices, which already contain acetaldehyde or for strong-tasting drinks, such as soft drinks. For bottled water, low acetaldehyde content is quite important, because if nothing masks the aroma, even extremely low concentrations (10-20 parts per billion parts of resin, by weight) of acetaldehyde can produce an off-taste. The thermal and thermooxidative degradation results in poor processibility characteristics and performance of the material. R-phrases , , S-phrases , , , Flash point −39 °C Autoignition temperature 185 °C RTECS number AB1925000 Supplementary data page Structure and properties n, εr, etc. ... Vulcanization is an example of cross-linking. ... diffusion (disambiguation). ... A soft drink is a drink that contains no alcohol. ...


One way to alleviate this is to use a copolymer. Comonomers such as CHDM or isophthalic acid lower the melting temperature and reduces the degree of crystallinity of PET (especially important when the material is used for bottle manufacturing). Thus the resin can be plastically formed at lower temperatures and/or with lower force. This helps to prevent degradation, reducing the acetaldehyde content of the finished product to an acceptable (that is, unnoticeable) level. See copolymers, above. Other ways to improve the stability of the polymer is by using stabilizers, mainly antioxidants such as phosphites. Recently, molecular level stabilization of the material using nanostructured chemicals has also been considered. A heteropolymer, also called a copolymer, is a polymer formed when two different types of monomer are linked in the same polymer chain. ... Isophthalic acid, or benzene-1,3-dicarboxylic acid, is a dicarboxylic acid, with formula C6H4(COOH)2. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...


Antimony

Antimony trioxide (Sb2O3) is a catalyst that is often used in the production of PET. It remains in the material and can thus in principle migrate out into food and drinks. Although antimony trioxide is of low toxicity, its presence is still of concern. The Swiss Federal Office of Public Health investigated the amount of antimony migration, comparing waters bottled in PET and glass: the antimony concentrations of the water in PET bottles was higher, but still well below the allowed maximal concentrations.[1] (report available in German and French only) The Swiss Federal Office of Public Health concluded that small amounts of antimony migrate from the PET into bottled water, but that the health risk of the resulting low concentrations is negligible (1% of the "tolerable daily intake" determined by the WHO). A later (2006) but more widely publicized study by a group of geochemists at the University of Heidelberg headed by William Shotyk found similar amounts of antimony in water in PET bottles.[2] Antimony trioxide is the most important commercial compound of antimony. ... It has been suggested that this article or section be merged into Catalysis. ... For other uses, see Concentration (disambiguation). ... WHO redirects here. ...


The most recent WHO risk assessment for antimony in drinking water can be found here: [3]


Re-crystallization

PETE has SPI resin ID code 1
Recrystallized PET

PET can be used to explore the crystallization of amorphous solids. The resin identification code can be used to verify the type of plastic it is made of: many plastic beverage bottles have the letters PET or PETE and a code of 1 on the bottom, near the center. When a flame is held several inches below the bottle and slowly brought closer, part of the material will visibly change. This happens because high temperatures melt the PET. This releases the tension that was frozen in during the blow molding process and the polymer chains will shift to a more relaxed and disordered state, which results in shrinkage of the softened area. Because of the decreased order of the polymer chains, there are now fewer crystal nuclei. Consequently, when the crystallites re-form upon cooling they grow larger than the original crystallites in the bottle wall. Because the new crystallites are larger than the wave length of light, they will now cause light to scatter, giving the material an opaque white appearance. Image File history File links Resin-identification-code-1-PETE.svg‎ Self made from PNG. File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Resin-identification-code-1-PETE.svg‎ Self made from PNG. File historyClick on a date/time to view the file as it appeared at that time. ... The Society of the Plastics Industry developed symbols for plastics so that they could be recycled easier. ... Sorted household plastic waiting to be hauled away for reprocessing. ... Image File history File linksMetadata Download high-resolution version (1401x978, 251 KB) PET plastic which has been heated over a candle then cooled, recrystallising in the process. ... Image File history File linksMetadata Download high-resolution version (1401x978, 251 KB) PET plastic which has been heated over a candle then cooled, recrystallising in the process. ... Frost crystallization on a shrub. ... Wax and paraffin are amorphous. ... Sorted household plastic waiting to be hauled away for reprocessing. ... A crystallite is a domain of solid-state matter that has the same structure as a single crystal. ...


Processing equipment

There are two basic molding methods, one-step and two-step. In two-step molding, two separate machines are used. The first machine injection molds the preform. The preform looks like a test tube. The bottle-cap threads are already molded into place, and the body of the tube is significantly thicker, as it will be inflated into its final shape in the second step using stretch-blow molding. Stretch-blow molding is a processing method for the manufacture of biaxially oriented plastic containers. ...


In the second process, the preforms are heated rapidly and then inflated against a two-part mold to form them into the final shape of the bottle. Preforms (uninflated bottles) are now also used as containers for candy.


In one-step machines, the entire process from raw material to finished container is conducted within one machine, making it especially suitable for molding non-standard shapes (custom molding), including jars, flat oval, flask shapes etc. Its greatest merit is the reduction in space, product handling and energy, and far higher visual quality than can be achieved by the two-step system. Jar can mean: Containers: Antique fruit jar Canopic jar, used in ancient Egyptian burial Leyden jar, a simple capacitor Killing jar [municipality in Zaqatalskiy region of Azerbaijan] JAR (file format) is a file format used to package Java programming language applications Jar, Norway, a centre in the municipality of B...


References

  1. ^ http://www.goodfellow.com/csp/active/STATIC/E/Polyethylene_terephthalate.HTML

See also

Recycling of PET Bottles is the activity whereby bottles made out of PET are collected, sorted and processed in order to reuse the material out of which they are made. ... Biaxially-oriented polyethylene terephthalate (boPET) polyester film is used for its high tensile strength, chemical and dimensional stability, transparency, gas and aroma barrier properties and electrical insulation. ... Sorted household plastic waiting to be hauled away for reprocessing. ...

External links

  • American Plastics Council info on plastic bottles, refilling, PET safety
  • Information on PET, detailed information of PET uses in different bottles

  Results from FactBites:
 
Polyethylene terephthalate - Wikipedia, the free encyclopedia (1686 words)
Depending on its processing and thermal history, it may exist both as an amorphous (transparent) and as a semi-crystalline (opaque and white) material.
It can be synthesized by a transesterification reaction between ethylene glycol and dimethyl terephthalate.
Replacing terephthalic acid (right) with isophthalic acid (center) creates a kink in the PET chain, interfering with crystallization and lowering the polymer's melting point.
Process for preparing easily dyeable polyethylene terephthalate fiber - Patent 5108675 (5679 words)
The polyethylene terephthalate usable for the present invention may be prepared by known polymerization processes and may optionally contain a thermal stabilizer, a flatting agent, ar anti-static agent, or the like.
The polyethylene terephthalate fiber according to the present invention should have an initial modulus of from 60 g/d to 130 g/d, preferably from 70 g/d to 120 g/d.
In the process according to the present invention, the polyethylene terephthalate filaments extruded from the spinneret are passed through a heating zone defined over a length of not less than 5 cm from the bottom surface of the spinneret and are maintained at a temperature of from 150.degree.
  More results at FactBites »

 
 

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