Polybutylene terephthalate processing

Zimmer brochure, PBT- Polybutylene Terephthalate Process, http //www. lurgi.com/website/fileadmin/pdfs/brochures/PBTProcess en.pdf... 

In addition to the desired polymerization reaction, the dialcohol reactants can participate in deleterious side reactions. Ethylene glycol, used in the manufacture of polyethylene terephthalate, can react with itself to form a dialcohol ether and water as shown in Fig. 24.4a). This dialcohol ether can incorporate into the growing polymer chain because it contains terminal alcohol units. Unfortunately, this incorporation lowers the crystallinity of the polyester on cooling which alters the polymer s physical properties. 1,4 butanediol, the dialcohol used to manufacture polybutylene terephthalate, can form tetrahydrofuran and water as shown in Fig. 24.4b). Both the tetrahydrofuran and water can be easily removed from the melt but this reaction reduces the efficiency of the process since reactants are lost. 

Polyethylene terephthalate is most often extruded into films or fibers, or blow molded into bottles. Polybutylene terephthalate is primarily found in injection molded parts. Such parts are highly crystalline, which makes them opaque. Polybutylene terephthalate is often modified with glass fibers or impact modifiers. Table 24.1 contains applications by processing method and resin. 

Table 24.1 Applications of polyethylene terephthalate and polybutylene terephthalate by processing method...

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. 

What properties of polybutylene terephthalate make it amenable to injection molding processing ... 

The most recent entrant-to the. club of commodity chemicals is 1,4-butanediol (BDO), a petrochemical used in some of the more specialized applications such as chemical intermediates for the production of tetrahydro-furane and gama-butyrolactone, polybutylene terephthalate, and the more familiar polyurethanes. Traditionally, the Reppe process was the primary route to BDO, based bn acetylene and formaldehyde feeds. More recently, the share of BDO from butane and propylene oxide based production has grown rapidly. 

The most important commercial blends of BPA-PC are poly(acrylonitrile-butadiene-styrene) (PC/ABS) and polybutylene terephthalate (PC/PBT) or polyethylene terephthalate (PET). Commercial grades of PC/ABS include CYCOLOY (GE), Bayblend (Bayer), and PULSE (Dow). PC/ABS blends exhibit improved flow and processability and enhanced low-temperature impact strength in comparison to PC (Fig. 3). These blends are widely used in applications requiring enhanced impact resistance, such as interior automotive parts and computer and electronics applications such as computer housings and cell phones. Non-halogenated flame-retardant PC/ABS blends are widely available. Poly(acrylic-styrene-acrylonitrile) (PC/ ASA) blends (GELOY , GE Luran , BASF) provide improved weatherability for outdoor applications such as exterior automotive parts, but exhibit reduced impact performance at low temperatures in comparison to PC/ABS. PC/PBT or PET blends (XENOY , GE Makroblend , Bayer) provide enhanced chemical resistance and weatherability for applications such as lawn and garden equipment and automotive bumpers and fasdas. 

The effect of compatibilization of grafted or block copolymers as controllers of interphase interaction has been well known (1,28). Marosi and Bertlan (29), for example, described the compatibUizing effect of polybutylene terephthalate-polytetramethylene oxide block copolymers on PA6/HDPE blends. The addition of a block copolymer prevents separation in the blends during processing and increases the impact strength of the material several times. 

Ford Sierra featured the first all-plastic bumper in Europe, and the Ford Taurus and Sable featured the first of these bumpers in the United States. The bumper is molded from GE s Xenoy polycarbonate (PC)/polybutylene terephthalate (PBT) blend. The high impact strength of PC, combined with the resistance to gasoline and oil and the processing ease of PBT, has boosted the use of PC/PBT blends in car bumpers. Bayer s PC/PBT blends are called Makrolon PR. They are used for several automobile impact-resistant parts. 

Thermoplastic alloy of styrene maleic anhydride copolymer and polybutylene terephthalate. Has improved dimensional stability and tensile strength. Processed by injection molding. Also called SMA PBT Alloy. 

Jie H, Ke H, Wenjie Q, Zibin Z. Process analysis of depolymerisation polybutylene terephthalate in supercritical methanol. Polym Degrad Stab 2006 91 (10) 2527-2531. 

Ultrasonic welding is the most common thermal assembly process used with polybutylene terephthalate parts. However, heated tool welding and other welding methods have provided satisfactory joints when bonding PET and PBT to itself and to dissimileu- materials. 

TPUs and polycarbonate blends and TPU/polycarbonate/ABS blends are used with the addition of the polycarbonate giving higher modulus and solvent stress cracking resistance as well as making processing of the TPU much easier. TPU/polycarbonate/polybutylene terephthalate blends are superior to their ABS analogue for resistance to environmental stresscracking resistance. 

Out-of-autoclave curing process in polymer matrix composites 467 Linear polybutylene terephthalate... 

C. S.Wang, and C. S. Lin, Catalyst composition for production of polybutylene terephthalate via direct esterification process, US Patent 5,900,474,1999. 

The two major TPs are polybutylene terephthalates (PBT) and polyethlene terephthalates (PET). These crystalline, high-molecular-weight polymers h ive an excellent balance of properties and processing characteristics. Unreinforced and glass-fiber-reinforced grades... 

PAA polyaryl amide PAI polyamide-imide PAN polyacrylonitrile PB polybutylene PBA physical blowing agent PBI polybenzimidazole PBNA phenyl- -naphthylamine PBT polybutylene terephthalate PC permeability coefficient PC personal computer PC plastic composite PC plastic compKJunding PC plastic-concrete PC polycarbonate PC printed circuit PC process control PC programmable circuit PC programmable controller PCB polychlorinated biphenyl PCB printed circuit board PCE perchloroethene PCR post-consumer resin pcf pounds per cubic foot... 

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