Seal Chemical Industries

Ozark Fluorine Specialties Seal Chemical Industries Solvay Group (Belgium)... 

Seal Chemical Industries Sumitomo Chemical (Japan)... 

Parts made from fluoroelastomers ate used ia appHcations that justify their high cost, usually where the maintenance and replacement costs are high enough to offset the initial cost of the part. These include automotive appHcations such as valve stem seals, fuel injector components, radiator, crankcase and transmission seals, and carburetor needle tips. Numerous seals and gaskets in the marine, oilfield, and chemical processing industries employ fluoroelastomers. In addition, many hoses in the automotive and chemical industry are made entirely of fluoroelastomer compounds or have a veneer of the fluoroelastomer as a barrier exposed to the harsh environment. Seals and gaskets in military appHcations and the binder for flares and missile appHcations ate made with fluoroelastomers. 

Optical purity can be quantitatively assayed by HPLC after reducing a sample to the amine with triphenylphosphine. A 50-mg sample was diluted with 10 1 THF water (1 mL in a screw cap vial) and treated with triphenylphosphine (190 mg). Gas evolution begins within 5 min once this subsides the reaction is sealed and placed in an oil bath at 50°C for 30 min. The mixture is diluted with HCIO4 (pH 1.0,1 mL) and washed with dichloromethane (2 x 1 mL). The acidic water phase contains the salt of the amine. A 200-pL sample was diluted to 1 mL and assayed by HPLC using a Crownpak CR(+) column (Diacel Chemical Industries) HPLC conditions aqueous pH 1.0 HCIO4, flow 0.5 mL/min, UV detection at 210 nm. The product had an enantiomeric excess of 96%, major enantiomer, Rt 3.4 min, and minor enantiomer, Rt 5.0 min. 

Valve seats, piston rings for hydraulic installations for the chemical industry, seals and other parts for high-vacuum installations usable up to 300°C without lubrication. .. Cryogenic insulation in PI foams. .. 

The other major springboard for the fluorocarbon chemical industry was the "Manhattan Project to develop the atomic bomb. This required the large-scale production of highly corrosive elemental fluorine and uranium(VI) fluoride for the separation of the radioactive 235U isotope. Oils capable of resisting these materials were needed to lubricate pumps and compressors, and polymers were needed to provide seals. Peril uorinated alkanes and polymers such as PTFE and poly(chlorotrifluoroethylene) (PCTFE) proved to have the appropriate properties so practical processes had to be developed for production in the quantities required. In 1947 much of this work was declassified and was published in an extensive series of papers3 which described the fundamental chemistry on which the commercial development of various fluoro-organic products, especially fine chemicals, was subsequently based. 

One of the most applied high-pressure standards for the piping components is based on the so--called IG-Standard, which was established by an association of the German Chemical Industry beginning with 1930. Similar developments took place in the US and elsewhere. The pipes applied are of seamless design. The joints and seals which have been approved for high-pressure are shown in Fig. 4.2-1. 

Fabrics coated with FEP and PFA can be laminated and heat-sealed into protective garments, canopies, etc. FEP-coated polyimide films are used in electronics and as a wire tape. FEP-based anticorrosion coatings are used in the chemical industry and as chemical barriers.18 A thin coating of FEP or PFA can be used as a hot melt adhesive for a variety of substrates, including PTFE-coated fabrics and laminates. 

A wide variety of excellent pumps is available in the chemical industry. It is sometimes a problem to choose the best from the large number available. This discussion will be limited to centrifugal pumps. Assuming that one has sized the pump, decided on a centrifugal pump, and chosen a suitable list of vendors, the main choices involve (1) metallurgy, (2) seal-less pumps versus conventional centrifugal pumps, and (3) the type of seals for conventional pumps. 

Seal-less pumps are becoming very popular and are widely used in the chemical industry. Mechanical seal problems account for most of the pump repairs in a chemical plant, with bearing failures a distant second. The absence of an external motor and a seal is appealing to those experienced with mechanical seal pumps. However, do not assume that just because there is no seal, seal-less pumps are always safer than pumps with seals, even with the advanced technology now available in seal-less pumps. Use seal-less pumps with considerable caution when handling hazardous or flammable liquids. 

Increasing international competition and poor public perceptions could jeopardise the sustainability of the EU chemical industry. REACH is a once-in-a-lifetime opportunity and the stakes are high. Whether REACH seals or opens the coffin for many EU chemical businesses will depend on the finer details of its implementation, which appears to be in the hands of the EU Member States, the European Commission and the new European Chemicals Agency. 

Large quantities of PTFE are used in the chemical industry in fluid-conveying systems as gaskets, seals, molded packing, bellows, hose, and lined pipe [11] and as lining of large tanks or process vessels. PTFE is also used in laboratory apparatus. Compression-molded parts are made in many sizes and shapes (Figure 4.13). 

Chlorotrifluoroethylene telomer lubricants are used primarily where chemical inertness and nonflammability are required. The chemical industry and the cryogenic gas industry (primarily oxygen) are the major users of these materials. They are used to lubricate all types of process equipment, such as dryers, conveyers, pumps, valves, and compressor seals. Extreme pressure tests using the four-ball method show that they are good lubricants, without any seizure even at an applied load of 800 kg. 

---