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Viton® made with APA > Technical Info > Technical Papers Technical Papers

Subject and Authors	Where Given	Availability
A New Broadly Fluid Resistant Fluoroelastomer Based on APA Technology, Viton® Extreme™ ETP-S by T. M. Dobel and R. Stevens	ACS Fall Meeting, Cleveland, OH, October 14-17, 2003	Please order directly from ACS.
Viton® Extreme™ ETP fluoroelastomer is a unique, peroxide cured fluoroelastomer that exhibits the broadest fluids resistance of any hydrogen containing fluoroelastomer. This type of Viton® is designed for severe applications that require a combination of fluid resistance not obtainable with normal FKM polymers. ETP can resist both aromatic hydrocarbons and alcohol-like high fluorine FKM, and in addition, can resist polar solvents like methyl ethyl ketone as well as both strong acids and bases. Viton® Extreme™ ETP-600S, developed under the number VTR-8710, has all the chemical resistance normally associated with this type of Viton®. In addition, ETP-600S has much improved processing characteristics such as better mold flow, better mold release, and improved compression set resistance. Viton® Extreme™ ETP-S can be fabricated into seals, gaskets, extruded goods, and sheet stock much like standard fluoroelastomers, and provides a step change improvement in processing compared to current ETP-900 and ETP-500. Processing recommendations will be discussed.
A New, Improved Processing Base-Resistant Fluoroelastomer Based on APA Technology, Viton® Extreme™ TBR-S by J. Bauerle	ACS Fall Meeting, Cleveland, OH, October 14-17, 2003	Please order directly from ACS.
As used in this paper, the term "base resistance" refers to the ability of a vulcanizate, in general, to resist chemical attack by high pH compounds and thus to be able to resist a subsequent loss of, or change in physical properties. A number of fluoroelastomers are presently being promoted as "base-resistant" products, but until the development of the new FEPM-TBR-S, there were only three classes of fluoroelastomer that were inherently resistant to base attack: (1)Perfluoroelastomers (FFKM), (2)Viton® Extreme™ ETP-900, a terpolymer of ethylene, tetrafluoroethylene, and perfluoromethylvinyl ether, and (3)Dipolymers of tetrafluoroethylene and propylene. Compared to these three options, the new base-resistant polymer, FEPM-TBR-S, offers a superior combination of cost, inherent resistance to base attack, excellent mold release, and resistance to hydrocarbon fluids that is closer to that exhibited by conventional VF2/HFP/TFE fluoroelastomers (FKM).
New Peroxide Curable Fluoroelastomer Compositions With Outstanding Properties and Processing Characteristics by Dr. S. Bowers	IRC, July 2003	pdf available
Elastomers are specified in a variety of industrial, automotive and aerospace applications where large volumes of high quality seals, tubes and hose are needed to contain or transport a variety of gases and liquids. In the case of high volume applications like seals for automotive service, the need for efficient part manufacture is imperative to achieve the required balance of part quality and production economy. Ease of processing also impacts part quality since processing difficulties like mold sticking and fouling, or problems with mould filling or extrusion, can result in surface defects in seals and tubes. New fluoroelastomers based on Advanced Polymer Architecture (APA) technology comprise a redesigned main chain molecular structure as well as new chain termination and cure site chemistry. This paper introduces several new low viscosity versions of these peroxide curable fluoroelastomers, designed to deliver easy processing in the most difficult molding processes while retaining excellent properties.
A Review of Recent Progress in the Design and Reactions of Base-Resistant Fluoroelastomers by W. Schmiegel	IRC, July 2003	pdf available
The ease of proton abstraction from carbon-hydrogen compounds that are partially fluorinated is a specific function of structure. Despite their long demonstrated outstanding heat and oil resistance generally, and good acid resistance when crosslinked by peroxides, VF2-based fluoroelastomers are intrinsically highly reactive toward soluble bases. It should not be surprising that elastomers that can be crosslinked in less than one minute at 200C and have a large excess of such Rf - VF2 -Rf curesites due to morphological requirements, are not able to withstand the attack of similarly basic species in service. Instead, the hydrogen content that is required of affordable elastomeric fluoropolymers to exhibit flexibility at service temperatures must be provided by hydrocarbon olefins like E or P. Elastomeric compositions that possess this superior level of base-resistance are TFE/P/curesite monomer and TFE/PMVE/E/curesite monomer.
The Effect of Molecular Weight on Properties of Fluoroelastomers Cured with Bisphenol AF by D. Lyons	ACS Spring Meeting, San Francisco, CA, April 28-30, 2003	pdf available
Three monodisperse vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene terpolymers were prepared by iodine degenerative chain transfer and used to assess the effect of molecular weight on compositions crosslinked with bisphenol AF. MN for the series ranged from 100,000 to 245,000 and polydispersities were ~1.3. Three sets of compounds were prepared from these polymers: unfilled with 3 phr/6 phr Ca(OH)s; filled with 3 phr MgO/6 phr Ca(OH)2; and unfilled with 9 phr MgO as the sole metal oxide. Hardness and tensile properties for the original vulcanizate and after 70 and 336 hours @ 200°C was determined for each compound. This was compared to compression set after similar aging. Compression sets for these compounds were excellent. An analysis of the hardness and compression set data for the unfilled compounds suggests that little if any chain scission is occurring during the first 70 hours of air aging.
New Fluoroelastomer Developments For Aerospace Sealing Applications by E. Thomas	ACS Spring Meeting, San Francisco, CA, April 28 - 30, 2003	pdf available
This paper reviews several new peroxide-curable fluorohydrocarbon elastomers capable of sealing from -45°C to +275°C in air, lubricating oils, and standard reference fluids. Evaluations highlight fluid compatibility and seal force retention in gas turbine engine oils. The new fluoroelastomers utilize Advanced Polymer Architecture designed to provide enhanced end-use properties, as well as significant improvements in processing behavior, which is essential in high quality, high yield fabrication of aerospace sealing devices.
Long-Term Performace of New, Improved Specialty Fluoroelastomers by T. Dobel, J. Bauerle	ACS Fall Meeting, Pittsburgh, PA USA, Oct. 8-12, 2002	pdf available
More aggressive environments in both automotive and industrial applications as well as a drive for longer part life are increasing the demand for specialty fluoroelastomers. Recent advances in the manufacture of fluoroelastomers have led to the development of several new specialty types of fluoroelastomer that provide significantly improved processing performance. This paper presents data on the long-term performance of these new specialty fluoroelastomers in a number of aggressive fluids, both automotive and industrial, to characterize their performance versus one another.
New Peroxide Curable Advanced Polymer Architecture Viton® for Plate Heat Exchange Gaskets (PHEG) Applications by S. Bowers	5th Journee Franco-Allemandes du Caoutchouc, Strasbourg, France, Sept 19-21, 2002	pdf available
There are several problems associated with the use of fluoroelastomers in heat exchangers. One of the most perplexing problems is that of corrosion of the titanium heat exchanger plates which are very expensive to replace. Other difficulties are associated with how to compound the fluoroelastomer to give good long term sealing integrity in the face of hostile service conditions which usually requires the use of lead oxide stabilized formulations. Last but not least are the manufacturing difficulties associated with the fabrication of such large and complex components. This paper describes how new materials of Viton made with Advanced Polymer Architecture offer excellent resistance to the relevant chemical media and can be compounded to give a lower level titanium corrosion without compromising other functional properties.
New Trends in Development of Fluoroelastomers by A. Nagasawa	SAE World Congress & Expo, Detroit MI, USA March 5, 2002	pdf available
(1)New Peroxide Curable Specialty Fluoroelastomers - DuPont Performance Elastomers has developed new polymerization and curing technology which transforms speciality fluoroelastomers by largely eliminating deficiencies in compression set, heat resistance and demolding performance. The author describes the new products, commercially available early in 2002, that provide demolding characteristics approaching standard bisphenol cured materials, fast cure rates, excellent heat resistance and very low compression set.(2) "New Injection Moldable Bisphenol Curable Fluoroelastomer Precompound":-Fluoroelastomers are generally cured using a poly-hydroxy system comprising a cross linker such as bisphenol AF that provides excellent performance and processing characteristics. Injection molding of fluoroelastomers has become popular mainly because of lower production cost, but the compound must have much higher flow, cure and demolding characteristics than for commpression molding. The author discusses DuPont Performance Elastomers' new advanced precompounding technology combined with rheologically improved polymer that offers outstanding flow and demolding characteristics.
New Developments in Base-Resistant Elastomers by J.G. Bauerle	SAE World Congress & Expo, Detroit MI, USA March 5, 2002	Please order directly from SAE (details mentioned above).
One of the most important aspects of "base-resistance" in automotive sealing applications is long-term resistance to amine-based lubricant additives. A disadvantage of currently available elastomers that are actually capable of providing long-term resistance to base attack is the poor resistance to hydrocarbon fluids exhibited by these polymers, relative to conventional FKM. The author presents fluid aging data from tests run on a new base-resistant polymer that demonstrates excellent resistance to lubricant additives, and improved resistance to the hydrocarbon base fluids used in various automotive oils and greases.
A new FKM for Fuel Systems by R. Stevens	SAE World Congress & Expo, Detroit MI, USA March 5, 2002	Please order directly from SAE (details mentioned above).
Fluoroelastomers are premium sealing materials for automotive fuel systems. FKM-GFLT is one of the foremost, showing excellent fuel resistance and good low temperature flexibility and sealing capability. Now a new fluoroelastomer, VTR-88525, has been developed with many of the same attributes, plus -40°C dry static sealing capability, and part serviceability with little or no postcure of the elastomer. The author compares it to the current GFLT and other fuel system sealing materials. Fuel, alcohol, and ether resistance as well as low temperature sealing measurements are reviewed with a specific focus on automotive fuel system end use requirements.

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