Tel: +86 20 36013580 +86 20 36013581 +86 20 36013445 Fax: +86 20 36013583 Email: [email protected]O – Rings & Basic Seals O-Ring X-Rings & Square Rings O-Ring Sizing Chart Encapsulated O Ring O-Ring Kits & Cord Hydraulic & Fluid Seals Rotary shaft seals Custom Molded Shapes Custom Rubber Seals Gaskets Bonded Seal Custom Machined Parts PTFE Products PTFE Rotary Shaft Seals Materials The proper material is critical for maximum performance. DKI utilizes a wide range of superior performance materials for every conceivable application. Material class and type details NITRILE HYDROGENATED NITRILE FLUOROCARBON ETHYLENE- PROPYLENE POLYURETHANE SILICONE FLUOROSILICONE NATURAL RUBBER NEOPRENE STYRENE BUTADIENE POLYACRYLATE ETHYLENE ACRYLIC Virgin PTFE PTFE Filled ACETAL NYLON PEEK PSU PPSU PEI PET PVDF E-CTFE PPE PE-UHMW PVC NITRILE Rubber (NBR, Buna-N, Nitrile) Nitrile is the most widely used elastomer in the seal industry. The popularity of nitrile is due to its excellent resistance to petroleum products. It has good physical properties and is superior to most rubbers in regards to compression set, tear and abrasion resistance. It offers high resistance to mineral oil based hydraulic fluids, silicone greases, petroleum-based oils, water and alcohols. The major limiting properties of nitrile are its poor ozone and weather resistance and moderate heat resistance, but in many applications these are not limiting factors. Temperature Range (dry heat) low high -22 °F -30 °C 212 °F 100 °C Application Advantages >excellent compression set >good tear resistance >good abrasion resistance >good petroleum-based oils resistance >good mineral oil based hydraulic fluids resistance >good solvent, water and alcohols resistance Primary Uses Application Disadvantages Pneumatic seals, O-Rings, Oil seal lips, Gaskets, Washer and low pressure hydraulic seals. It can be used with a back-up ring in higher pressure applications. This is the most popular o-ring material and custom molded rubber components for: Oil resistant applications poor weather resistance moderate heat resistance not suited for using in brake fluids Not suited for using in highly polar solvents Materials: Viton, Nitrile, Silicone, Polyurethane, EPDM, Fluorosilico... http://www.dkirubber.com/materials.asp 1 dari 13 25/03/2013 14:43
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Nitrile is the most widely used elastomer in the seal industry.The popularity of nitrile is due to its excellent resistance topetroleum products. It has good physical properties and issuperior to most rubbers in regards to compression set, tearand abrasion resistance. It offers high resistance to mineraloil based hydraulic fluids, silicone greases, petroleum-basedoils, water and alcohols.The major limiting properties of nitrile are its poor ozone andweather resistance and moderate heat resistance, but inmany applications these are not limiting factors.
Temperature Range (dry heat)
low high
-22 °F-30 °C
212 °F100 °C
Application Advantages
>excellent compression set>good tear resistance>good abrasion resistance>good petroleum-based oils resistance>good mineral oil based hydraulic fluidsresistance>good solvent, water and alcohols resistance
Primary Uses Application Disadvantages
Pneumatic seals, O-Rings, Oil seal lips, Gaskets, Washerand low pressure hydraulic seals. It can be used with aback-up ring in higher pressure applications. This is themost popular o-ring material and custom molded rubbercomponents for:Oil resistant applications
poor weather resistancemoderate heat resistancenot suited for using in brake fluidsNot suited for using in highly polar solvents
Low temperature applicationsFuel systems, automotive, marine, and aircraftGeneral Industrial Use
HYDROGENATED NITRILE (HNBR)
HNBR is achieved by hydrogenated NBR. Greatly improvedwear and extrusion resistance over standard NBR. Goodchemical compatibility and it is excellent heat and oilresistant including exposure to such oil additives asdetergents, anti-oxidants and anti-wear agents. It alsoshows a up to five times higher resistance to sour gas andozone resistance. Has an extended high temperature range.
Temperature Range (dry heat)
low high
-22 °F-30 °C
300 °F149 °C
Application Advantages
> excellent heat and oil resistance>improved fuel and ozone resistance(approximately 5X over Nitrile)>excellent abrasion, compression set, tensiles,and tear properties>exhibit better wear resistance than standardnitrile
Primary Uses Application Disadvantages
Seal and gasket application requiring additional resistanceto chemicals and slightly higher temperatures than can behandled with NBR. O-Rings, washers, rod and piston seals,back-up rings, gaskets.
increased cold flow with hydrogenationdecreased elasticity at low temperatures withHydrogenation over standard nitrileNot use for exposure to ketone, esters, aromaticfluids
FLUOROCARBON (FKM,Viton)
An excellent elastomer for use in high temperatureapplications. Also exhibits excellent chemical resistance,commonly referred as VITON or FKM. Fluorocarbon exhibitsresistance to a broader range of chemicals combined withvery good high temperature properties more so than any ofthe other elastomers. It is the closest available approach to auniversal elastomer for sealing in the use of o-rings andother custom seals over other types of elastomers.Fluorocarbons are highly resistant to swelling when exposedto gasoline as well as resistant to degradation due to exposeto UV light and ozone.In addition to standard FKM materials, a number of specialmaterials are available with differing monomer compositionsand fluorine content (65% to 71%) for improved lowtemperature, high temperature, or chemical resistanceperformance.Fluorocarbons exhibit low gas permeability making them wellsuited for hard vacuum service and many formulations areself-extinguishing. FKM materials are not generallyrecommended for exposure to hot water, steam, polarsolvents, low molecular weight esters and ethers, glycol
Temperature Range (dry heat)
low high
-4 °F-20 °C
392 °F200 °C
Application Advantages
>excellent chemical resistance>excellent heat resistance>good mechanical properties>good compression set resistance>Resistance to wide range of oils and solvents;specially all aliphatic, aromatic and halogenatedhydrocarbons, acids, animal and vegetable oils
based brake fluids, or hot hydrofluoric or chlorosulfonicacids.
Primary Uses Application Disadvantages
O-rings, rubber seals and custom molded rubbercomponents for:Automotive fuel handlingAircraft engine sealsHigh temperature applications requiring good compressionset performanceTough sealing applications requiring extreme chemicalresistanceGeneral industrial seals and gaskets
poor low temperature flexibilitypoor resistance to hot water and steamnot recommended for exposure to hot water,steam, polar solvents, low molecular weightesters and ethers, glycol based brake fluids, orhot hydrofluoric or chlorosulfonic acids.
ETHYLENE-PROPYLENE (EPDM)
Ethylene-propylene compounds are used frequently to sealin brake systems, and for sealing hot water and steam. Ethylene propylene compounds have good resistance tomild acids, detergents, alkalis, silicone oils and greases,ketones, and alcohols. They are not recommended forapplications with petroleum oils, mineral oil, di-esterlubricants, or fuel exposure.Ethylene Propylene has gained wide seal industryacceptance for its excellent ozone and chemical resistanceproperties and is compatible with many polar fluids thatadversely affect other elastomers.EPDM compounds are typically developed with a sulfur orperoxide cure system. Peroxide-cured compounds aresuitable for higher temperature exposure and typically haveimproved compression set performance.
Temperature Range (dry heat)
low high
-40 °F-40 °C
302 °F150 °C
Application Advantages
>exceptionally good weather aging and ozone>resistance>excellent water and chemical resistance>excellent resistance to gas permeability and>aging due to exposure to steam>good in ketones and Alcohols>good heat resistance>good low temperature flexibility
Primary Uses Application Disadvantages
standard and special sealing applications as hydraulic orrotary seal, O-rings, flange seals and gasketsWater system seals, faucets, etc.Brake systemsOzone exposure applicationsAutomotive cooling systemsGeneral Industrial Use
poor petroleum oil and solvent resistancenot recommended for food applicationsnot recommended for exposure to aromatichydrocarbons
POLYURETHANE (AU) (EU)
Millable polyurethane exhibits excellent abrasion resistanceand tensile strength as compared to other elastomersproviding superior performance in hydraulic applications
with high pressures, abrasive contamination and shockloads.Its outstanding features are high resistance to abrasion, lowcompression set, high rigidity and high tear strength.Polyurethane is used in industrial hydraulic systems (lipseals, chevron packings, wipers, rod seals, piston seals,O-rings and special seals), where improved performanceand service life is important. It is resistant to petroleum oils,hydrocarbon fuels, ozone and weathering is good.
-22 °F-30 °C
230 °F110 °C
Application Advantages
> excellent abrasion resistance>excellent tensile strength and high rigidity>low compression set>good resistance to petroleum oils andhydrocarbon fuels>good weather and ozone resistance
Primary Uses Application Disadvantages
Static and dynamic seals (standard and special), wiper,O-rings, back-up rings, flange seals, rotary seals:seals for high hydraulic pressurehighly stressed parts subject to wear
poor resistance to waterpoor high temperature capabilities
SILICONE (VMQ)
Silicone is a semi-organic elastomer with outstandingresistance to extremes of temperature with correspondingresistance to compression set and retention of flexibility.Silicone elastomers also have excellent weathering, ozoneand aging properties.Silicone rubbers have poor mechanical properties andabrasion resistance and are therefore mainly used for staticsealing applications and are not recommended for dynamicapplications. Silicones are highly permeable to gases, andare generally not recommended for exposure to ketones,concentrated acids, or steam.
Temperature Range (dry heat)
low high
-78 °F-60 °C
392 °F200 °C
Application Advantages
> excellent extreme temperature properties>excellent compression set resistance and goodresilience>moderate solvent resistance>highly resistance to oxidation and ozone attackvery clean, low odor and taste
Primary Uses Application Disadvantages
O-rings, rubber seals and custom molded rubbercomponents for:seals (static) for extreme temperature applicationsfood applicationsmedical devicesFDA applications
typically not good for dynamic seals due tofriction properties and poor abrasion resistancenot recommended for most concentratedsolvents, oils, concentrated acids and dilutesodium hydroxide
FLUOROSILICONE (FVMQ)
Fluorosilicone rubber which combines the good high and lowTemperature Range (dry heat)
temperature stability of Silicone with the fuel oil and solventresistance of Fluorocarbons. It is most often used inaerospace applications for systems requiring fuel and/ordiester-based lubricant resistance up to a dry heat limit of400° F. Its features good compression set and resilienceproperties. It is suitable for exposure to air, ozone,chlorinated and aromatic hydrocarbons.
Fluorosilicone is designed for static sealing use. Because ofits limited physical strength, poor abrasion resistance andhigh friction characteristics. Fluorosilicone is notrecommended for dynamic sealing applications. It is alsonot recommended for exposure to brake fluides, hydrazine,or ketones
low high
-78 °F-60 °C
347 °F175 °C
Application Advantages
>excellent extreme temperature properties>excellent compression set resistance and good>resilience>good fuel oil resistance>very clean, low odor and taste
Primary Uses Application Disadvantages
O-rings, rubber seals and custom molded rubbercomponents for:seals (static) for extreme temperature applicationsaircraft fuel systems
typically not good for dynamic seals due tofriction properties and poor abrasion resistancenot recommended for exposure to brake fluides,hydrazine, or ketones
NATURAL RUBBER (NR)
Natural rubber is a product coagulated from the latex of therubber tree, hevea brasiliensis. Natural rubber features lowcompression set, high tensile strength, resilience, abrasionand tear resistance, good friction characteristics, excellentbonding capabilities to metal substrate, and good vibrationdampening characteristics
Temperature Range (dry heat)
low high
-60 °F-51 °C
220 °F104 °C
Application Advantages
> excellence compression set>good resilience and abrasion>good surface friction properties>high tear strength>low crack growth>good low temperature properties
Primary Uses Application Disadvantages
O-rings, rubber seals and custom molded rubbercomponents for:rubber to metal bonded vibration isolators and mountsautomotive diaphragmsFDA applications for food and beverage seals
poor resistance to attack by petroleum oilspoor ozone, UV resistance
Neoprene homopolymer of chlorobutadiene and is unusualin that it is moderately resistant to both petroleum oils andweather (ozone, UV, oxygen). This qualifies neopreneuniquely for certain sealing applications where many othermaterials would not be satisfactory. Neoprene is classifiedas a general purpose elastomer which has relatively lowcompression set, good resilience and abrasion, and is flexcracking resistant.Neoprene has excellent adhesion qualities to metals forrubber to metal bonding applications.It is used extensively for sealing refrigeration fluids due to itsexcellence resistance to Freon and ammonia.
Temperature Range (dry heat)
low high
-40 °F-40 °C
250 °F121 °C
Application Advantages
>high resilience with low compression set>moderate resistance to petroleum oils>good resistance to ozone, UV, oxygen>excellence resistance to Freon and ammonia
Primary Uses Application Disadvantages
O-rings, rubber seals and custom molded rubbercomponents for:refrigeration industry applicationsgeneral purpose seals, hose and wire
moderate water resistancenot effective in solvents environments