Polyethylene terephthalate production

Within the technologies of polyethylene terephthalate production, this chapter focuses on nonpolymer modifications. That means, that speciality products based on bicomponent systems (combinations with different polymers), and polymer additives (for anti-pilling, antistatic, flame-retardant, antibacterial and heat resistance properties) are not specifically described. 

Recycled Polyethylene Terephthalate Products Global Market... 

Those polymers which are the condensation product of two different monomers are named by applying the preceding rules to the repeat unit. For example, the polyester formed by the condensation of ethylene glycol and terephthalic acid is called poly(oxyethylene oxyterphthaloyl) according to the lUPAC system, as well as poly (ethylene terephthalate) or polyethylene terephthalate. 

The primary substrates or support iaclude many types of paper and paperboard, polymer films such as polyethylene terephthalate, metal foils, woven and nonwoven fabrics, fibers, and metal cods. Although the coating process is better suited to continuous webs than to short iadividual sheets, it does work very well for intermittent coating, such as ia the printing process. In general, there is an ideal coater arrangement for any given product. 

Friedrich et al. also used XPS to investigate the mechanisms responsible for adhesion between evaporated metal films and polymer substrates [28]. They suggested that the products formed at the metal/polymer interface were determined by redox reactions occurring between the metal and polymer. In particular, it was shown that carbonyl groups in polymers could react with chromium. Thus, a layer of chromium that was 0.4 nm in thickness decreased the carbonyl content on the surface of polyethylene terephthalate (PET) or polymethylmethacrylate (PMMA) by about 8% but decreased the carbonyl content on the surface of polycarbonate (PC) by 77%. The C(ls) and 0(ls) spectra of PC before and after evaporation of chromium onto the surface are shown in Fig. 22. Before evaporation of chromium, the C(ls) spectra consisted of two components near 284.6 eV that were assigned to carbon atoms in the benzene rings and in the methyl groups. Two additional... 

As mentioned earlier, polyethylene terephthalate is an important thermoplastic. However, most PET is consumed in the production of fibers. 

The most generally useful polyester is that made by reaction between dimethyl terephthalate (dimethyl 1,4-benzenedicarboxylate) and ethylene glycol (1,2-ethanediol). The product is used under the trade name Dacron to make clothing fiber and tire cord and under the name Mylar to make recording tape. The tensile strength of polyethylene terephthalate) film is nearly equal to that of steel. 

Perhaps the most important polyester is polyethylene terephthalate), commonly known as PET (or PETE 1 on plastic beverage bottles). The annual production of PET in the United States is of the order of 108 kg (105 metric tons). Much of this is converted into fabric (trade name, Dacron) or magnetically coated film (Mylar). 

PE. See polyethylene (PE) pendulum test method perfonnance of product design affecting predicting process and penneability of plastic PET. See polyethylene terephthalate (PET)... 

The performance properties of PEN present opportunities for replacement of rayon or polyamide in carcass construction. The use of PEN cord in these applications is currently being evaluated in both Asia and Europe. PEN has demonstrated acceptable flexural fatigue equivalent to polyethylene terephthalate (PET) and rayon. It has equivalent toughness to rayon, which is important for sidewall impact resistance. PEN s superior mechanical properties also afford opportunities to use less fiber in carcass construction enabling production of lighter-weight, more fuel-efficient tires. 

Terephthalic acid (p-TA or TA), a raw material for polyethylene terephthalate (PET) production, is one of the most important chemicals in petrochemical industry. Crude terephthalic acid (CTA), commonly produced by homogeneous liquid phase p-xylene oxidation, contains impurities such as 4-carboxybenzaldehyde (4-CBA, 2000-5000 ppm) and several colored polyaromatics that should be removed to obtain purified terephthalic acid (PTA). PTA is manufactured by hydropurification of CTA over carbon supported palladium catalyst (Pd/C) in current industry [1]. 

When the new product to be manufactured is the same as what it started as, for example a new bottle made from bottle scrap, the recycling is referred to as closed-loop. When the new application is different from the starting one, the process is referred to as open-loop recycling, as is the case when the polyethylene terephthalate bottle is used to produce polyester fiber for carpeting. 

Because polyethylene terephthalate crystallizes slowly, it can readily be produced in its amorphous state. This is especially true when it is used in packaging materials, such as thin films and carbonated drink bottles. The final products exhibit high clarity and directionally balanced properties because they lack crystalline regions. 

Polyesters exhibit excellent high temperature strength and electrical properties making them a good choice for many demanding applications. They also are physiologically inert allowing them to be used in food contact applications. The two common polyesters, polyethylene terephthalate and polybutylene terephthalate, are both used in injection molded products. Polyethylene terephthalate is often used in both extrusion and blow molded processes also. 

The trade name of a polyester fibre used as textile reinforcement for mbber in products such as tyres, belting and hose. It is a truly synthetic fibre made from polyethylene terephthalate, a condensation product of terephthalic acid and ethylene glycol. 

With the exception of ethylene vinyl acetate added in the 1980 s, the list of materials and polymers approved as packaging for food irradiated products has remained static for decades. This article supplies details of the approved list, which includes such polymers as polyethylene terephthalate and polyvinyl chloride. The article provides an update on the latest proactive move to expand the list of packaging materials and polymers approved for the irradiation of foods. The expanded list would include ethylene vinyl alcohol, PVC film, ionomers, nylon 66, 6/12 and copolyesters among others. 

Other textile fibers such as polyethylene terephthalate came into production first in England and then in America. The English discovered the fiber and the Americans discovered the film. When it was drawn bi-axially, polyethylene terephthalate gave a very good film which has had wide use. 

POLYETHYLENE TEREPHTHALATE (PET) has been used for a long time only as raw material for the production of films and fibers. 

Oxidation is the first step for producing molecules with a very wide range of functional groups because oxygenated compounds are precursors to many other products. For example, alcohols may be converted to ethers, esters, alkenes, and, via nucleophilic substitution, to halogenated or amine products. Ketones and aldehydes may be used in condensation reactions to form new C-C double bonds, epoxides may be ring opened to form diols and polymers, and, finally, carboxylic acids are routinely converted to esters, amides, acid chlorides and acid anhydrides. Oxidation reactions are some of the largest scale industrial processes in synthetic chemistry, and the production of alcohols, ketones, aldehydes, epoxides and carboxylic acids is performed on a mammoth scale. For example, world production of ethylene oxide is estimated at 58 million tonnes, 2 million tonnes of adipic acid are made, mainly as a precursor in the synthesis of nylons, and 8 million tonnes of terephthalic acid are produced each year, mainly for the production of polyethylene terephthalate) [1]. 

Hovenkamp, S. G. and Munting, J. P Formation of diethylene glycol as a side reaction during production of polyethylene terephthalate, J. Polym. Sci., Part A-1, 8, 679-682 (1970). 

The workhorse polyester is polyethylene terephthalate) (PET) which is used for packaging, stretch-blown bottles and for the production of fibre for textile products. The mechanism, catalysis and kinetics of PET polymerization are described in Chapter 2. Newer polymerization techniques involving the ring-opening of cyclic polyester oligomers is providing another route to the production of commercial thermoplastic polyesters (see Chapter 3). 

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