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Polyethylene terephthalate is produced largely from purified terephthalic acid (PTA), as well as to a lesser extent from (mono-)ethylene glycol (MEG) and dimethyl terephthalate (DMT). [ 41 ] [ 5 ] As of 2022, ethylene glycol is made from ethene found in natural gas , while terephthalic acid comes from p-xylene made from crude oil .
The solvent also modifies the curing rate and viscosity of the paint in its liquid state. There are two types of paint: solvent-borne and water-borne paints. Solvent-borne paints use organic solvents as the primary vehicle carrying the solid components in a paint formulation, whereas water-borne paints use water as the continuous medium.
Virtually the entire world's supply of terephthalic acid and dimethyl terephthalate are consumed as precursors to polyethylene terephthalate (PET). World production in 1970 was around 1.75 million tonnes. [8] By 2006, global purified terephthalic acid (PTA) demand had exceeded 30 million tonnes.
The most common and highest volume produced polyester is Polyethylene terephthalate (PET), which is an example of a saturated polyester and finds utilization in such applications as fibers for clothing and carpet, food and liquid containers (such as a water/soda bottles), as well as films. [11]
The terephthalate polymer PETE and the phthalate ester plasticizers are chemically different substances. [83] Despite this, however, many studies have found phthalates, such as DEHP in bottled water and soda. [84] One hypothesis is that these may have been introduced during plastic recycling. [84]
With 18% market share of all plastic materials produced, it ranges third after polyethylene (33.5%) and polypropylene (19.5%) and is counted as commodity plastic. There are several reasons for the importance of polyethylene terephthalate:
Most coatings have four basic components. These are the resin, solvent, pigment and additive systems [5] but the resin or binder is the key ingredient. Continuing environmental legislation in many countries along with geopolitics such as oil production are ensuring that chemists are increasingly turning to waterborne technology for paint/coatings and since resins or binders are the most ...
Polyethylene terephthalate can be hydrolyzed to terephthalic acid and ethylene glycol under high temperature (200-300 °C) and pressure. The resultant crude terephthalic acid can be purified by recrystallization to yield material suitable for re-polymerization: