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PRODUCT DEVELOPMENT INFORMATION
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FLUOROCARBON RUBBER (FKM RUBBER) – ITS OVERVIEW
oils and solvents and unusually high chemical resistance.
for FFKM.
depends on the choice of the Monomers.
Fluorocarbon Rubbers, designated by FKM (earlier it was designated as FPM), is the SSSSSSspecialised Rubber, which
are very stable, characterised by extreme Heat, Fire Resistance, Resistance to Oxidation, Ozone, swelling to
As per the ASTM D2000/SAE J200 system of classification, FKM & FFKM (PerFlourinated fluorocarbon
rubber) occupies the top performance range, in the rubber category & is designated as HK – for FKM & KK
FKM Rubber is made as Co-polymer, Ter-polymer and SSSSSSSSSSSspecial blends to meet the rigorous end requirements,
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Monomers being used for the manufacturing of FKM rubbers are as follows:
And other monomers like
f Ethylene (E)
f Propylene(E)
are also used for the special type of FKM Rubber
Depends on the combination of the monomers, different sub-type/sub-classification of FKM rubber is being
manufactured world-wide, viz.
f CO-POLYMER
f TER-POLYMER
f TER-POLYMER – PEROXIDE CURABLE
f SPECIAL LOW TEMPERATURE PEROXIDE CURABLE
f BASE RESISTANT
f PERFLUORO ELASTOMER – FFKM
Based on the ASTM D1418, FKM RUBBER is classified as 5 types as follows:
TYPE 1 CO-POLYMER OF Hexafluoropropylene & Vindylidenefluoride 3 HFP+VF2
TYPE 2TER-POLYMER of Tetrafluoroethylene, vinylidenefluoride & hexafluoroprpylene 3 TFE+VF2+HFP
TYPE 3TER-POLYMER of Tetrafluoroethylene, fluorinated vinylether & vinylidenefluoride 3 TFE+PFMVE / PAVE+VF2
TYPE 4TER-POLYMER of Tetrafluoroethylene, propylene & vinylidene fluoride 3TFE+P+VF2
PENTA-POLYMER of Tetrafluoroethylene, hexafluoropropylene,
TFE+HFP+VF2+E+PFMVE/PAVE
f Vinylidene Fluoride (VF2) CH2=CF2
f Hexa FluoroPropylene(HFP) CF2=CF-CF3
f Tetra FluoroEthylene(TFE) CF2=CF2
f PerFluoroMethyl Vinyl Ether(PFMVE)/ CF2=CF-O-CF3
PerfluoroAlkyl VinylEther(PAVE)
f 1-HydroPentaFluoroPropylene(HPFP) CHF=CF-CF3
f TriFluoroChloroEthylene(TFClE) CFCl=CF2
TYPE 5 vinylidenefluoride, ethylene & a fluorinatedalkylvinylether 3
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For FFKM(PERFLUOROELASTOMER) the combination of the monomers are Tetrafluoroethylene,
perfluoromethyl vinyl ether and a special cure-site monomer 3 TFE+PFMVE/PAVE+X
FKM Rubber is cured by Diamines, Bisphenol A/organophosphonium salt, Peroxide(only peroxide curable
grades) and TAIC.
FKM RUBBERS are available COMMERCIALLY as GUM Rubbers (Curatives needs to be added during
compounding), Cure incorporated ones (only acid acceptors, fillers & processing aids need to be added),
The commonly used ingredients are as follows:
FILLER – BLACKMT BLACK, FURNACE BLACK like SRF, FEF, HAF(at limited dosage), AUSTIN BLACK, conductive black, graphite,...
FILLER-WHITEBarium Sulfate, Diatomaceous Silica, Calcium Meta silicate, , Rutile TiO2, calcium carbonate, ppt. Silica, micronized PTFE,....
PROCESSING AIDS
PETS, PE WAX, VEGETABLE WAX, Amine based, Zinc Stearate, Low volatile plasticisers are not used in FKM. Low molecular weight FKM in liquid form can be used.
ACID ACCEPTORS MgO, CaO, ZnO, Pb3O4 & with Ca(OH)2,
CURING SYSTEM used in FKM RUBBER:
Curing Type Characteristics
DIAMINE CURING SYSTEM General purpose cure system
BISPHENOL A / Organophosphonium saltFor Improved compression set resistance and most commonly used system nowadays.
PEROXIDEFor peroxide curing type FKM, good resistance to acid, steam & amine based media.
FOR FFKM
Depends on the curing point, following cure system is being used• For Phenoxy group 3 Bisphenol AF• For Bromine/Iodine 3 TAIC• For CN group 3 Tin based via Triazine
formation.
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POST-CURING OF FKM:
All the grades of FKM needs to be post-cured and for peroxide based grades a post-curing of 4-8 hrs. @
stabilisation of curing. Post-cure increases the heat stability of the rubber because during the post-curing
cycle, heat-stable aromatic cross-links are formed and it will give good compression set resistance.
Generally post curing is done at the temperatures of 205deg.C, 232 deg.C and 250 deg.C&above. It is better to
keep the products in the post curing cycle, by starting the oven temperature either from room temperature
or from around 90 deg.c in a step of 20 – 25 deg.C/hr, till the desired post curing temperature is reached, to
achieve better properties in the FKM products.
Application of FKM:
In the high-temperature resistance and corrosive chemicals and hot-oil resistance requirements, also as a
binder for powdered rocket fuels, insulators in the low-voltage & frequency applications, etc.... in Automotive,
Aerospace, Chemical & Processing, Oil field/Mining, Semicon industries.
230 deg.C is sufficient & for other types of curing a minimum of 15/16 hr. – 24 hr. curing cycle is essential for the
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The Heat resistance of the FKM rubber is about 200 deg.C for continuous service, However, with increasing
temperature the service life gets shortens approximately as follows:
TEMPERATURE SERVICE LIFE
230 oC 3000 hr.
260oC 1000 hr.
290oC 240 hr.
315oC 48 hr.
FKM GRADES OF TECNOFLON are as follows:
Tecnoflon ® Bisphenol Curable
Tecnoflon ® Bisphenol Curable
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TECNOFLON – FKM & FFKM PRODUCT SELECTION GUIDE:
PRODUCT DEVELOPMENT INFORMATION
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Ram Charan Company | Samson Tower, 403, L – Pantheon Road, 6th Floor, Egmore, Chennai 600 008. Tamil Nadu, India.Phone : +91 44 4353 9040 • Fax : +91 44 4330 7050 • Email : [email protected] • Website : www.ramcharan.org
Mumbai | 098212 [email protected] Kolkata Hyderabad Chennai
Hosur Madurai Cochin Bangalore
New Delhi Pune Belgaum Coimbatore
VOLUME 2 • ISSUE 11 • MaRCH 2013
KINDLY NOTE: TECNOFLON IS MANUFACTURED BY M/S. SOLVAY SOLEXIS.