MFA > Materials
Choosing materials is one of the important tasks which require a lot of investigations, experiences and compromises between different desirable properties. At Mohandesi Farapardaz Arvand (Seal Jet Iran) we have great expertise in this area. We are well prepared to help you choosing the right material for your application.
For a given application there may be a number of different materials that are well suited, but our job is to find the best solution for you. This is often a combination between material properties and price. However, looking at the procurement price only is often very misleading, as this does not consider actual life-cycle cost for a given product. Downtime, equipment failure and repair cost due to a faulty seal is many times higher than the cost of the seal, even in cases when some of the more expensive materials are chosen.
Mohandesi Farapardaz Arvand (Seal Jet Iran) is dedicated to find the best overall sealing solutions and materials with special attention to functionality, reliability and low overall life-cycle cost.
Seals are faced with an ever increasing demand for higher pressure, temperature, functionality and longevity. This means that some of the more “traditional” materials no longer are as well suited as they used to be. Advances in material science are resulting in new and improved materials, suited to meet the increased demands.
Classification of sealing materials
In sealing technology, mainly two groups of macromolecular (polymer) substances are used: elastomers and thermoplastics. Macromolecular substances are organic compounds; its molecules consist of several thousands, often even millions of atoms, known as macro, giant, string or chain molecules. They can be created either by modification of highly molecular natural materials (e.g. natural rubber) or by depositing low-molecular elements (so called monomers) through various chemical reactions (synthetic materials, plastics).
Elastomers are materials that can be highly expanded by exerting relatively little power. Because of their structure, elastomers have a high retractibility, which means the compression set is very limited. There are two main groups of elastomers; rubber materials and thermoplastic elastomers. The rubber materials are polymers, which are formed by chemically cross-linked macromolecules with various vulcanization additives. Due to their chemical bonds they do not melt but rather begin to decompose at high temperatures. The cross-links also results in that the rubber materials don’t dissolve or, depending on the medium, swell or shrink.
The Thermoplastic Elastomers demonstrate the characteristic properties of elastomers over a wide temperature range, but with the processing behavior of thermoplastics. They can be melted at high temperature and can be processed with traditional thermoplastic processing techniques. Thermo plastic elastomers are soluble and they generally swell less in comparison to their chemically crosslinked equivalents. Engineering Thermoplastics are e.g. POM, PA, PTFE and Peek.
Thermoplastics can be melted. They are polymer materials, which are essentially harder and rigid at their application temperature compared to elastomers. Depending on the chemical structure, the properties vary from hard, to stiff, to ductile and flexible. Due to the morphological structure, extensive stretching is non-reversible and moulded parts remain in the deformed state. Thermoplastics are therefore called Plastomers. Engineering Thermoplastics are applied in the sealing technology for back-up rings and guide rings, bearing bushes, etc.
Thermoplastic elastomers belong to the elastomer family of materials. The elastomer family consists of materials that can be highly expanded by exerting relatively little power. Because of their structure, elastomers have a high retractability, which means the remaining deformation is very small.
Unlike elastomers (rubber), thermoplastic elastomers are physically but not chemically cross-linked. Therefore they can be melted at higher temperature and can be processed with traditional thermoplastic processing techniques. Thermoplastic elastomers are soluble; generally they swell less in comparison to their chemically cross-linked equivalents.
The thermoplastic elastomers of Mohandesi Farapardaz Arvand (Seal Jet Iran) are various types of polyurethanes from the company SKF (Economos). We are proud to be the only manufacturer of machined seals in Iran by using injection molded semi-finished polyurethane material.
Polyurethanes (TPU: Thermoplastic Polyurethane) have superior mechanical properties compared to elastomers (rubbers) and with the variety of different polyurethanes presented below, polyurethane will be the preferred material for many sealing systems.
H-ECOPUR is a hydrolysis-resistant thermoplastic polyurethane elastomer. It combines the engineering properties of ECOPUR with a high resistance to hydrolysis which is otherwise rarely found in polyurethanes. It is stable in water up to +90°C and has an outstanding stability in mineral oil. Because of its resistance to hydrolysis H-ECOPUR can be used for water hydraulic and for applications in steel plants, mining, tunneling and presses. H-ECOPUR is particularly recommended for the use in pure and seawater, for HFA and HFB fluids and biologically degradable hydraulic fluids (vegetable oils and synthetic esters) and food articles. H-ECOPUR is KTW approved and meets the FDA standards.
Temperature range from -20 ºC to 110 ºC
ECOPUR is a thermoplastic polyurethane elastomer (TPU), which has an unusually high abrasive resistance, low compression set, high physical properties and tear strength. In sealing technology ECOPUR is mostly used for U-cups, lip seals, wipers and packings, but it may also be used for dampers and other machined parts. Products made from this material can be used in mineral oil, in water up to 40°C and in bio-degradable hydraulic oils like vegetable oils and synthetic esters up to 60°C. Depending on the seal design and the housing conditions seals made of ECOPUR can be used up to 400 bar (for high pressure demands, experts from SKF recommend to use anti-extrusion-rings).
Temperature range from -30 ºC to 110 ºC
S-ECOPUR has been optimized with regard to the tribological characteristics friction and wear. This was achieved by the addition of a synergetic combination of solid lubricants. This special material is therefore best suitable for most severe applications in the water hydraulics and oil-free pneumatics.
Chemical properties are similar to H-ECOPUR.
Temperature range from -20 ºC to 110 ºC
T-ECOPUR is modified for low temperature applications. The properties of T-ECOPUR are similar those of ECOPUR, but the minimum service temperature is extended to -50°C. For that reason T-ECOPUR is most suitable for applications in severe climatic conditions and processes for frozen goods. T-ECOPUR has an unusually high abrasive resistance, low compression set, high physical properties and tear strength. Products made from this material can be used in mineral oil and in bio-degradable hydraulic oils like vegetable oils and synthetic esters.
Temperature range from -50 ºC to 110 ºC
G-ECOPUR is a casted hydrolysis-resistant polyurethane with similar properties to H-ECOPUR, especially regarding its chemical stability. G-ECOPUR can be used in the same hydraulic fluids as H-ECOPUR. Generally, G-ECOPUR is used for seals with a diameter from 540 mm up to 4000 mm as one piece and larger using our special welding technique.
Temperature range from -30 ºC to 110 ºC.
The composition of X-ECOPUR provides outstanding friction and wear properties as well as high pressure resistance. Therefore the material is well suited for the use as a composite seal, for wipers working in heavy-duty applications as well as for engineered plastic parts that require high elasticity and superior resilience.
Due to the exceptional extrusion resistance, seals made of this material work at higher pressure level and larger clearance, than those made of standard polyurethanes and PTFE compounds.
Temperature range from -30 ºC to 110 ºC
Compared to the standard grade H-ECOPUR, XH-ECOPUR has a significantly higher hardness. The composition of the material based on special raw materials provides outstanding friction and wear characteristics as well as pressure resistance. This material exhibits an outstanding chemical and hydrolysis resistance for applications in mineral oil, biodegradable hydraulic fluids (HETG and HEES, etc) and water based fluids (HFA and HFB). This material is specially developed to replace PTFE-based materials in sliding seals/composite seals (our profiles K08, S09 and others) in systems with adequate temperature and media (up to 110ºC and media as for H-ECOPUR). Used in composite seals, XH-ECOPUR exhibits greater resistance to extrusion, less leakage, longer life-time and easier installation properties than the traditional PTFE-based seals.
Temperature range from -20 ºC to 110 ºC
Compared to the S-ECOPUR standard material, XS-ECOPUR is harder and therefore further improves sliding properties. XS-ECOPUR has a better extrusion resistance than the standard material and therefore seals made of this material can be used at higher pressure, assuming the same profiles are used. XS-ECOPUR has been optimised in regard of the tribological characteristics (friction and wear), achieved by an addition of a synergetic combination of solid lubricants. The chemical properties are similar to H-ECOPUR. This material replaces PTFE-based materials for the same seals as XS-ECOPUR, but is better suited in systems where low friction is crucial (water hydraulics, badly lubricated etc.). XS-ECOPUR is most suitable for poor lubricated working conditions. The material can also withstand dry-running depending on the overall service conditions.
Temperature range from -20 ºC to 110 ºC
XG-ECOPUR is a casted hard grade hydrolysis resistant polyurethane most suitable for heavy duty large diameter (above 600 mm) applications. It has comparable chemical and mechanical properties to G-ECOPUR but with higher shore hardness and improved friction and wear characteristics.
Temperature range from -20 ºC to 110 ºC
Elastomers (rubbers) are materials that can be highly expanded by exerting relatively little power. Because of their structure, elastomers have a high retractability, which means the remaining deformation is very small. Elastomers, respectively rubber materials are polymers, which are chemically cross-linked by the vulcanization process. Due to their chemical bonds, they do not melt, but rather begin to decompose at high temperatures. In addition the cross-link ensures that rubber materials do not dissolve, and depending on the medium, do suffer more or less intensive swell or shrinkage.
Elastomers have in general inferior mechanical properties compared to polyurethanes. However the different elastomers display other qualities such as chemical and temperature resistance combined with elasticity, and are widely used for different types of seals.
Ecorubber-2 (FPM, FKM) brown
Ecorubber-3 (EPDM) black
Ecorubber-H (HNBR) balck
Ecosil (MVQ) reddish brown
Ecoflas (Aflas, TFE/P) black
Ecorubber-1 is an elastomer based on acrylonitrile-butadiene rubber (NBR), which is used for U-cups, packings, special seals and various components. This material has good resistance to mineral oils, greases and HFA, HFB and HFC pressure fluids. However, the material is not resistant to glycol-based fluids, HFD fluids, aromatic fluids (such as benzene), esters, ketones and amines or concentrated acids and bases. Ecorubber-1 is also available in a low-temperature grade, with a minimum working temperature of – 50ºC.
Temperature range from -30 ºC to 100 ºC
Eccorubber-2 is an elastomer based on fluororubber (FPM, FKM), also known as VITON (registered trade name of Du Pont), which can be used for U-cups, lip seals, packings, wipers and special seals. Its outstanding properties include high resistance to heat, ozone, many chemicals and it is all-weather-proof. Ecorubber-2 is compatible with mineral oils and greases containing sulphur, HFD pressure fluids (nearly all phosphate esters and chlorinated hydrocarbons), crude oil and sour gas. Ecorubber-2 is not resistant to anhydrous ammonia, amines, ketones, esters, hot water and low molecular weight organic acids. Ecorubber-2 is also available in a FDA compliant grade and with different hardness (75º-95º shore A).
Temperature range from -20 ºC to 200 ºC
Ecorubber-3 is an elastomer based on ethylene-propylene-diene rubber (EPDM), which can be used for U-cups, lip seals and packings. SKF Ecorubber-3 has an outstanding resistance to hot water, steam, washing agents and polar organic solvents. SKF Ecorubber-3 is not resistant to mineral oil and other unpolar media. The stability to weathering, ozone and ageing is good. If used in glycol-based brake fluids, national regulations have to be adhered to. RU3 is also available in a FDA compliant grade and a hard grade (93 º shore A).
Temperature range from -50 ºC to 150 ºC
Ecorubber-H is a hydrogenated nitrile butadiene rubbers, often referred to as HNBR, are saturated copolymers of acrylonitrile and butadiene, suitable for applications with aliphatic hydrocarbons, mineral oils and greases (for short times up to 170°C) and also for sulfonated crude oil. The physical and chemical properties vary depending on the polymer's composition.
Furthermore, it can be used in many diluted acids and bases and salt solutions even at elevated temperatures and in glycol-water mixtures. HNBR is not compatible with fuels with a high content of aromatic hydrocarbons (premium blend petrol), gasolines (petrol / alcohol blends) ketones, esters, ethers and chlorinated hydrocarbons like trichloroethylene and tetrachloroethy-lene. HNBR complies with FDA-recommendations. HNBR is also available in hard grade (93ºshore A), ED-grade, low-temperature grade (-40ºC) and ED/low-temperature grade (-30ºC).
Temperature range from -25 ºC to 150 ºC
Ecosil is a silicone rubbers (MVQ or VMQ) characterized by high thermal, weathering and ozone resistance. Owing to the poor mechanical properties, which are noticeably lower in comparison to other rubbers. Silicone rubbers are mostly used for static or quasi-static applications and should not be exposed to dry running. Ecosil is highly resistant against weathering, ozone and ageing, and also has a wide temperature range (-60 to 200 ºC). The compatibility with mineral oils depends on the content of aromatic hydrocarbons in the oil. Ecosil complies with FDA-recommendations.
Temperature range from -60 ºC to 200 ºC
Ecoflas is a unique fluoroelastomer based on an alternating co-polymer of tetrafluoroethylene and propylene (TFE/P). This material is chemically related to fluororubber.
Ecoflas has the following properties:
high resistance to mineral oils
outstanding resistance to hot water and hot stream up to 230°C
excellent resistance to sour gas and amines
excellent resistance to brake fluids (based on glycol, mineral oil or silicon oil) and fire-resistant hydraulic fluids)
good radiation resistance
Compared to fluororubber materials, Ecoflas shows slightly higher tensile strength and a similar heat resistance. Ecoflas is a tetraflourethylene-propylene material, often referred to as Aflas® (registered trade name of Asahi Glass), FEPM or TFE/P. This material is well suited against HFA, HFB, HFC and HFD liquids. In addition this material has excellent resistance against steam and hot water. Good resistance against various chemicals, and good mechanical properties means this material will often improve overall sealing effect in many systems currently using Viton® /FKM-materials or Perfluour/FFKM-materials.
Temperature range from -10 ºC to 200 ºC
Thermoplastics are polymer materials, which are essentially harder and rigid at their application temperature compared to elastomers. Depending on the chemical structure, the properties vary from hard, to stiff, to ductile and flexible. Due to the morphological structure, extensive stretching is non-reversible and moulded parts remain in the deformed state. Thermoplastics are therefore called “plastomers”. Thermoplastics have a wide range of properties, and depending on the material may display excellent chemical and temperature resistance, and good mechanical properties. We make a distinction between PTFE-based thermoplastics and other thermoplastics.
Thermoplastics include standard and special hard grade materials with outstanding wear resistance for mechanical applications and top performance PTFE compounds with highest chemical and temperature resistance, optimized for sealing applications and Advanced Engineered Plastic Parts (AEPP). Most of the materials comply with FDA regulations.
Polytetrafluoroethylene (PTFE) is a group of thermoplastic polymers that are compatible with a wide assortment of lubricants and feature chemical resistance that is far superior to that of any other sealing lip material. PTFE has a smooth, dirt-resistant surface. Seals with PTFE lips can accommodate high surface speeds while offering extended service life. The seals can tolerate dry running and are particularly valuable in highly contaminated applications because of their excellent exclusion ability.
Ecoflon 1 (virgin PTFE)
Ecoflon 2 (PTFE glass)
Ecoflon 3 (PTFE bronze)
Ecoflon 4 (PTFE carbon)
Other PTFE base materials
Ecoflon 1 is a thermoplastic material based on polytetrafluoroethylene (PTFE-virgin), which is used for back-up rings, packings, O-rings, rotary seals and gaskets. Ecoflon 1 has the widest application range of all sealing materials. Ecoflon 1 has an outstanding chemical resistance. When using PTFE for seals, the creeping behaviour of PTFE has to be considered. Ecoflon 1 complies with FDA regulations.
Temperature range from -200 ºC to 260 ºC
PTFE (polytetrafluorethylene) and PTFE-based materials have extremely good resistance to chemicals and will only be attacked by molten alkali metals and elementary fluor at high temperatures. However, for some of the PTFE-based materials the fillers may be attacked and destroyed by certain other chemicals. In addition these materials have a general working area between -200ºC and 260ºC, making them widely used for extreme conditions in respect to chemicals and temperature.
Ecoflon 2 is a polytetrafluoroethylene filled with glass fibres and molybdenum disulphide (PTFE with fillers) and can be used for U-cups, glide rings, back-up rings, packings and guide rings. Ecoflon 2 has good physical properties and significantly better creeping behaviour than virgin PTFE. The chemical resistance is similar to virgin PTFE.
FL2 is PTFE filled with glass fibres and molybdenum disulphide. Because of its special composition, FL2 has good physical properties and distinctly better creep behaviour than PTFE-virgin. Also higher wear resistance than most PTFE with fillers.
SKF Ecoflon 3 (PTFE +40% bronze) exhibits improved compression strength sliding properties as well as an improved thermal conductivity in comparison to virgin PTFE.
FL3 is PTFE filled with bronze. This material has good mechanical properties, and can be used at higher loads compared to FL2 and FL5.
Ecoflon 3F (PTFE +40% bronze) has, compared to SKF Ecoflon 3, improved wear and abrasion resistance and is colored green.
PTFE carbon (PTFE +25% carbon) shows improved mechanical strength, stiffness and hardness as well as improved sliding properties in comparison to virgin PTFE.
Ecoflon 5 (PTFE modified) exhibits improved wear and abrasion resistance in comparison to Ecoflon 1. The material is suitable for food and beverage applications.
FL5 is a modified PTFE. This material has the same chemical properties as PTFE-virgin, and is also defined as a homopolymer according to ISO 12086. FL5 has highly improved mechanical properties in comparison to PTFE-virgin, see also the “Suggested Materials” section.
Seal-Jet Iran considers FL5 to be our standard "PTFE-virgin". FL5 is compliant with FDA-regulations.
FL13 is a modified PTFE filled with carbon. This material is often used for rotating applications (swivel seals) and water hydraulics. FL13 has very low friction due to the integrated carbon. Since this material is based on modified PTFE, the mechanical properties are improved compared to standard PTFE with carbon.
In addition to the PTFE-based materials described above we can manufacture seals, gaskets and other details in a variety of other PTFE materials with fillers specifically suited for a given application. We have either in stock or with short delivery time approximately 20 different PTFE-based materials to offer.
Polyoxymethylene (POM) - also known as polyacetal or polyformaldehyde is a group of engineering thermoplastic materials with high stiffness, low friction and excellent dimensional stability.
POM1 is a semi-crystalline polyacetal-copolymer which is used for anti- extrusion rings, guide ring bushes, scrapers and for precision-machined parts with tight tolerances. POM1 is one of the most important engineering thermoplastics with good physical properties, low water absorption and good chemical resistance. POM1 can be used in mineral oils, in water-based fire-resistant hydraulic fluids (HFA, HFB and HFC fluids). Concentrated acids and bases will attack and destroy it. POM1 (white) may be used in applications for food and drug, and is compliant with BGVV and EC-regulations.
Temperature range from -50 ºC to 100 ºC.
Polyamides consist of a wide range of different types, which can be used for textiles, sportswear and engineered components. The types, used by SKF, are engineering thermoplastics with good sliding properties. Polyamides absorb water, therefore for applications in water or water-based fluids, the swelling of the material must be taken into account.
PA1 is a cast polyamide with good sliding properties and is used for back-up rings, guide rings and bearing components instead of POM1 for a diameters above 260 mm. PA1 can be used in mineral oils and water- based fire-resistant hydraulic fluids. When designing parts with PA1 for an application in water or water-based fluids, the swelling of the material must be taken into account, as PA1 absorbs water up to eight weight percent.
Temperature range from -40 ºC to 100 ºC.
Polyether ether ketones (PEEK) are engineering thermoplastics with high tensile strength, stiffness, high heat distortion temperature and good sliding and friction behaviour.
PEEK1 is a polyetheretherketon with high tensile strength, stiffness, high heat distortion temperature and good sliding and friction behaviour. In addition PEEK1 has good resistance against numerous chemicals, and is therefore often used in demanding applications with regards to pressure, temperature and chemicals, or when there is a combination of these parameters.
PEEK1 is compliant with FDA-regulations.
Temperature range from -60 ºC to 260 ºC.
Ecowear 1000 is a semi crystalline thermoplastic material based on ultrahigh molecular weight polyethylene with the following properties:
• low co-efficient of friction
• excellent wear resistance
• high impact strength (also at low temperature down to -200 °C)
• very high creep resistance
• no swelling
Ecowear 1000 is suitable for applications where outstanding sliding, wear or dry running properties. Ecowear 1000 is extremely resistant to abrasion and is often used for pneumatic systems, or as sealing against abrasive media. This material has excellent chemical resistance, low friction, very low water absorption and good extrusion resistance.
Ecowear 1000 is compliant to FDA-regulations.
Temperature range from -200 ºC to 90 ºC
SKF Ecopps is a partially crystalline material based on poly-phenylene sulfide (PPS) and has an outstanding hardness and modulus, high chemical and thermal resistance. The chemical and ionizing radiation resistance of SKF Ecopps is excellent and the maximum recommended service temperature is about 220°C for long term applications, although it will withstand 260°C for short periods of time.
SKF Ecotex is a compound based on a thermosetting polyester resin and reinforced with fabric inlays. Due to the addition of graphite, the material shows very good characteristics in respect to the tribological requirements of bearing materials in gliding systems. SKF Ecotex shows high compression strength and outstanding friction and wear properties. Therefore, it is very well suited for guide rings and bearing bushes. Due to the very low absorption of moisture, SKF Ecotex is particularly suitable for use in water and water-containing media (swelling in water <0,1 %)
In addition to the materials mentioned above Seal Jet Iran can manufacture seals and other machined details in almost any other thermoplastic, each with unique properties to suit a given application. Most of these materials are also available with different fillers, widening the range of applications even more.
We offer machined seals and details in materials such as: PA, POM, PET, PE, PP, PVC, PMMA, ABS, PC, PSU, PES, PPS, PPSU, PEI, PAI, PBI, and PI.
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No. 8, 6th St., Abidi St., 8th Km, Karaj Special Rd., 13897 Tehran , Iran