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Speciality Rubbers for ORing Seals. An R.A.E. Investigation

Speciality Rubbers for ORing Seals. An R.A.E. Investigation filler was a fine fumed silica, and the curative was 2, 5 dimethyl-2, 5 ditertiary butyl peroxy hexane sup­ Speciality Rubbers for ported in finely divided calcium carbonate. Compounding was car­ ried out on a 150 x 50 mm (6 x 2") O-Ring Seals. two-rol l rubber mill. Some of the best results are show n in the table. An R.A.E. Investigation Interestin g unconventional material s ONE of the main connections that One grade cannot meet all Althoug h no attempt was made to rubber has with the subject of industrial requirements optimize formulations with regard tribology is for O-ring seals, and in Although there are at least 15 to filler loading and concentration vie w of the saying that "efficient different types of specialty rubber of curative, some interesting mate­ lubrication is impossible without available, applications still arise in rials emerged from the range of efficient sealing," O-rings are just whic h no single grade can meet the compositions covered. For example, as important as any other oil seal. requirements, eg, nitrile rubbers of the addition of 20 parts by weight of the butadiene-acrylonitrile co­ polymer to methyl silicone resulted in a composite network having a TEST RESULTS DURING AN INVESTIGATION BY THE RAE ON THE substantially higher modulus and CO-VULCANIZATION OF TWO SPECIALTY RUBBERS TO PRODUCE COMPOSITE tear strength than methyl silicone RUBBER NETWORKS WITH PROPERTIES TAILORED TO SPECIFIC NEEDS alone, but with a virtually identical performance at low temperatures. Tensil e Elongatio n 100 % Clash-Berg * It is also seen that the low- Compositio n strengt h modulu s a t break temperatur e temperature flexibility of the nitrile MN/m 2 MN/m 2 % °C rubber can be improved consider­ methyl-viny l silicone 5-2 1·3 36 8 -7 3 ably, without loss of modulus or methyl-viny l silicone/ 80/2 0 6·1 19 3 -6 9 extensibility, by addition of small 3-7 butadiene-acrylonitnle copolymer ■ 50/50 7· 5 20 0 4·9 7 -4 0 amounts of methyl silicone. 40/6 0 8 8 25 0 5 0 -3 0 butadiene-acrylonitnl e copolymer 11· 8 3 5 26 5 -1 8 butadiene-acrylonitnle copolymer/ 80/2 0 14 0 3 9 29 5 -1 8 Increasing tensile strength viny l fluorosilicone gumstock 50/5 0 9· 3 4· 6 22 0 -2 4 20/8 0 6·1 10 7 5·4 -5 9 and elongation The addition of 20 parts by weight viny l fluorosilicone gumstock 6-6 3· 3 17 2 -6 7 of nitrile rubber to the fluorosilicone produced a vulcanizate wit h a much *Temperature at which the torsional stiffness of the rubber reaches a value of 70 Mn/m2. higher modulus and hardness, while retaining excellent low temperature properties. On the other hand, the W e are therefore interested in an medium acrylonitrile content have a addition of 20 parts of fluorosilicone investigation by the Royal Aircraft combination of mechanical proper­ to nitrile rubber resulted in a signi­ Establishment at Farnborough which ties an d fuel and oil resistance which ficant increase in tensile strength, has show n that the co-vulcanization makes them attractive for aircraft modulus and breaking elongation. of two specialty rubbers can pro­ applications, but their lack of Tests on composites made from duce composite rubber networks elasticity and resilience at sub-zero butadiene-acrylonitrile copolymer wit h properties tailored for specific temperatures limits their usefulness. (whic h has an excellent resistance applications. Using conventional Silicone rubbers have outstanding to kerosene) and methyl silicone rubber-working equipment and wit h resistance to high and low tem­ (whic h swells when in contact with nitrile and silicone rubbers as peratures, but their applications are kerosene) indicated that the uptake starting materials, composite net­ limited because of low mechanical of kerosene varied linearly with the works were produced with greater strength, particularly tear strength. composition ratio of the network. low-temperature flexibility than nit­ rile rubbers but having similar Elastomers are commercially mechanical strength. Similarly, com ­ available posites were fabricated which had Elastomers used in these in­ Composit e network s successful higher strength than methyl silicone vestigations by the RAE were a Thus composite networks offer and fluorosilicone rubbers, but with commercially available butadiene- the prospect of formulating vul- comparable low-temperature flexi­ acrylonitnle copolymer of medium canizates with a closely-controlled bility. Limited additions of fluoro­ acrylonitrile content, a methyl-vinyl degree of swell, an important silicone to nitrile rubbers resulted in silicone, a vinyl-fluorosilicone gun- property in the development of networks with good compression- stock, and a filled but uncatalyzed O-ring seal design—and indeed in set resistance up to 160°C in air. vinyl fluorosilicone. The reinforcing any rubber sealing mechanism. INDUSTRIAL LUBRICATION AH D TRIBOLOGY, july/August. 1974 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Industrial Lubrication and Tribology Emerald Publishing

Speciality Rubbers for ORing Seals. An R.A.E. Investigation

Industrial Lubrication and Tribology , Volume 26 (4): 1 – Apr 1, 1974

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0036-8792
DOI
10.1108/eb053067
Publisher site
See Article on Publisher Site

Abstract

filler was a fine fumed silica, and the curative was 2, 5 dimethyl-2, 5 ditertiary butyl peroxy hexane sup­ Speciality Rubbers for ported in finely divided calcium carbonate. Compounding was car­ ried out on a 150 x 50 mm (6 x 2") O-Ring Seals. two-rol l rubber mill. Some of the best results are show n in the table. An R.A.E. Investigation Interestin g unconventional material s ONE of the main connections that One grade cannot meet all Althoug h no attempt was made to rubber has with the subject of industrial requirements optimize formulations with regard tribology is for O-ring seals, and in Although there are at least 15 to filler loading and concentration vie w of the saying that "efficient different types of specialty rubber of curative, some interesting mate­ lubrication is impossible without available, applications still arise in rials emerged from the range of efficient sealing," O-rings are just whic h no single grade can meet the compositions covered. For example, as important as any other oil seal. requirements, eg, nitrile rubbers of the addition of 20 parts by weight of the butadiene-acrylonitrile co­ polymer to methyl silicone resulted in a composite network having a TEST RESULTS DURING AN INVESTIGATION BY THE RAE ON THE substantially higher modulus and CO-VULCANIZATION OF TWO SPECIALTY RUBBERS TO PRODUCE COMPOSITE tear strength than methyl silicone RUBBER NETWORKS WITH PROPERTIES TAILORED TO SPECIFIC NEEDS alone, but with a virtually identical performance at low temperatures. Tensil e Elongatio n 100 % Clash-Berg * It is also seen that the low- Compositio n strengt h modulu s a t break temperatur e temperature flexibility of the nitrile MN/m 2 MN/m 2 % °C rubber can be improved consider­ methyl-viny l silicone 5-2 1·3 36 8 -7 3 ably, without loss of modulus or methyl-viny l silicone/ 80/2 0 6·1 19 3 -6 9 extensibility, by addition of small 3-7 butadiene-acrylonitnle copolymer ■ 50/50 7· 5 20 0 4·9 7 -4 0 amounts of methyl silicone. 40/6 0 8 8 25 0 5 0 -3 0 butadiene-acrylonitnl e copolymer 11· 8 3 5 26 5 -1 8 butadiene-acrylonitnle copolymer/ 80/2 0 14 0 3 9 29 5 -1 8 Increasing tensile strength viny l fluorosilicone gumstock 50/5 0 9· 3 4· 6 22 0 -2 4 20/8 0 6·1 10 7 5·4 -5 9 and elongation The addition of 20 parts by weight viny l fluorosilicone gumstock 6-6 3· 3 17 2 -6 7 of nitrile rubber to the fluorosilicone produced a vulcanizate wit h a much *Temperature at which the torsional stiffness of the rubber reaches a value of 70 Mn/m2. higher modulus and hardness, while retaining excellent low temperature properties. On the other hand, the W e are therefore interested in an medium acrylonitrile content have a addition of 20 parts of fluorosilicone investigation by the Royal Aircraft combination of mechanical proper­ to nitrile rubber resulted in a signi­ Establishment at Farnborough which ties an d fuel and oil resistance which ficant increase in tensile strength, has show n that the co-vulcanization makes them attractive for aircraft modulus and breaking elongation. of two specialty rubbers can pro­ applications, but their lack of Tests on composites made from duce composite rubber networks elasticity and resilience at sub-zero butadiene-acrylonitrile copolymer wit h properties tailored for specific temperatures limits their usefulness. (whic h has an excellent resistance applications. Using conventional Silicone rubbers have outstanding to kerosene) and methyl silicone rubber-working equipment and wit h resistance to high and low tem­ (whic h swells when in contact with nitrile and silicone rubbers as peratures, but their applications are kerosene) indicated that the uptake starting materials, composite net­ limited because of low mechanical of kerosene varied linearly with the works were produced with greater strength, particularly tear strength. composition ratio of the network. low-temperature flexibility than nit­ rile rubbers but having similar Elastomers are commercially mechanical strength. Similarly, com ­ available posites were fabricated which had Elastomers used in these in­ Composit e network s successful higher strength than methyl silicone vestigations by the RAE were a Thus composite networks offer and fluorosilicone rubbers, but with commercially available butadiene- the prospect of formulating vul- comparable low-temperature flexi­ acrylonitnle copolymer of medium canizates with a closely-controlled bility. Limited additions of fluoro­ acrylonitrile content, a methyl-vinyl degree of swell, an important silicone to nitrile rubbers resulted in silicone, a vinyl-fluorosilicone gun- property in the development of networks with good compression- stock, and a filled but uncatalyzed O-ring seal design—and indeed in set resistance up to 160°C in air. vinyl fluorosilicone. The reinforcing any rubber sealing mechanism. INDUSTRIAL LUBRICATION AH D TRIBOLOGY, july/August. 1974

Journal

Industrial Lubrication and TribologyEmerald Publishing

Published: Apr 1, 1974

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