Oil and gas production handbook An introduction to oil and gas production

Figure 24. Aromatics – xylene and polyester chain, derivatives 
 
One of the forms of xylene, paraxylene, is used to make polyesters which 
have applications in clothing, packaging and plastic bottles.  
 
The most widely-used polyester is polyethylene terephthalate (PET), used in 
lightweight, recyclable soft drink bottles (30% of production), as fibers in 
clothing (60% of production), as a filling for anoraks and duvets, in car tire 
cords and conveyor belts. It can also be made into a film that is used in 
video and audiotapes and X-ray films. Polyester makes up about 18% of 
world polymer production and is the third most-produced polymer; 
polyethylene (PE) and polypropylene (PP) are first and second, respectively. 
 
Metaxylene is an isomer of mixed xylene. It is used as an intermediate in the 
manufacture of polyesters for coatings, inks, reinforced plastics and 
packaging applications. 
 
Unsaturated polyester is used over a broad spread of industries, mainly the 
construction, boat building, automotive and electrical industries. In most 
applications, they are reinforced with small glass fibers. Hence, these 
plastics are commonly referred to as glass reinforced plastics (GRP).  
Initially a liquid, the resin becomes solid by cross-linking chains. A curative 
or hardener creates free radicals at unsaturated bonds, which propagate in a 

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chain reaction to adjacent molecules, linking them in the process. Styrene is 
often used to lower viscosity and evaporates during hardening, where the 
cross linking releases heat. 
 
Orthoxylene is an isomer of mixed xylene. It is primarily used in plasticizers 
(primarily in flexible polyvinyl chloride (PVC) material to make it more 
flexible), medicines and dyes. 
 
Alkyd resins are a group of sticky synthetic resins used in protective coatings 
and paints. 
 
7.1.2 Toluene, benzene, polyurethane and phenolic 
chain