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Elastomer Availability

Common Elastomer Availability from MEMBRANO_FLEX Ltd. Div of LDI Ltd
for you to choose from:-
 
Information Source - edited from "KEVIN-TECH" aka Kevin Bebb's
Technical Notes - LDI Ltd.  in-house proprietary , since 1963.
The compound ingredient percentages are chosen by LDI Ltd. to cause
similar physical properties, and from advice by the Rubber &
Plastics Research Association (aka RAPRA.) and others. :-
 
In the uncured / un-polymerized state,:
To be easily transfer-injectable over distances greater than 3x the
item diameter, without the use of long oil alkids etc. for
plasticization.
 
In the cross linked / polimerized state, to have
1. Elongation at break in excess of 600%,
2. UTS grater than 2000 psi (140 bar)
3. IRH Shore "A" scale hardness 55-60,
4. Compression set resistance for seal-points. ETC.
 
MATERIAL TO CHOOSE FROM.
Note - "LDI" are not compatibility engineers .
Be sure to check your selection against the "O" rings Seal, gasket,
valve diaphragm, pump packings that have proved satisfactory for
your system.
Errors and Omissions Excepted. "E&OE"
--------------------------------------------------------------------
 
ASTM ELASTOMER DESIGNATIONS WITHIN LDI Ltd (MembranoFlex)
AVAILABILITY :-
"FFKM", "PIB" , "EP" "EPDM" "EPR" , "ECO", "FKM", "CSPE", "NR",
"CR", "NBR", "MQ, VMQ, PVMQ, FVMQ,"  "T Also ST".   Etcetera

Aflas TM Perfluoro-elastomer
tetrafluoro-ethylene-propylene
aka "FFKM"
Temperatures  450 Degrees F
tear resistance POOR
Typical Uses  Sour Service - H2S
Other
More Detail  http://www.darcoid.com/includes/tetrafluoroethylene---
propylene-aflas.html

Butyl Rubber
Poly-Iso-Butylene
aka "PIB" ,  newer Halobutyl
Not easily "bondable".
Temperatures
tear resistance fail
Typical Uses  Automobile inner tubes
Other   Oxygen permeation resistance
More Detail http://en.wikipedia.org/wiki/Butyl_rubber
 
Nordel TM  EPCAR TM , VISTALON TM
Generic - EPT Ethylene Propylene Terpolymer Peroxide Cured
aka EP,"EPDM" (D M Diamine-Monomer not understood - it is no longer
a monomer when polimerized),
aka also "EPR".
Temperatures 300 F
tear resistance  good
Typical Uses water based, wide applications (not OILS, Hydrocarbons)
Other   Good abrasion resistance, low cost
More Detail  http://www3.interscience.wiley.com/journal/104021283/
abstract?CRETRY =1&SRETRY=0
 
Epichlorohydrin
aka "ECO"
Temperatures High and Low
tear resistance fair
Typical Uses resistance to fuel oil,
Other   http://www.hubeichem.com/products-e2.htm
More Detail    http://www.primasil.com/polymers/text.asp?PageId=42

Fluoro Elastomers
aka "FKM"
Trade names Fluorel TM, Viton TM
Common variants "A", "B", "B50","E60C", "GS"
Temperatures HIGH
tear resistance BAD
Typical Uses, result of much hype, Viton TM Thought to be a panacia.
Other  Expensive, elongation / elasticity very poor, & NOT for low
temperature use at all.
More Detail  http://www.knovel.com/web/portal/browse/display?_EXT_
KNOVEL_DISPLAY_ bookid=1323
 
Hypalon TM (Per Dupont is Obselecent)
Chloro-Sulfonated PolyEthylene
aka "CSPE" & synthetic rubber (CSM)
Temperatures :- extremes
tear resistance
Typical Uses  Chemical Resistance
Other
More Detail http://en.wikipedia.org/wiki/Hypalon

Natural Rubber "Indico"
aka "NR"
Temperatures moderate
tear resistance good , ebrasion resistance  good
Typical Uses ambient temperature hose
Other  Highly elastic - diametric opposite to fluoro-elastomers.
More Detail  http://www.rubber-stichting.info/

Neoprene   generic "polychloroprene"
aka "CR"
Temperatures  Good high temp aging resistance
tear resistance  Fair
Typical Uses Automotive parts
Other resists some specialty chemicals
More Detail
http://www.dupontelastomers.com/products/neoprene/neoprene.asp
 
Nitrile rubbers,
Butadiene-Acrylonitrile,
aka "NBR"  (in a low grade aka "Buna N")
Common Variants :
a. Low temp Nitrile - to negative 70  50 F? C?
b. High Temp Nitrile -
c. Hydrogenated ("HNBR") Increase properties , and some CO2
   permiation resistance
d. FDA ingredient versions, White,
Temperatures according to variant
tear resistance,   Fair,  abrasion resistance good
Typical Uses   Hydrocarbon liquids, fluid power hydraulics
Other   Reasonable price
More Detail http://www.ashtabularubber.com/nitrile-page.html
 
Silicone Rubber - wide varieties
aka MQ, VMQ, PVMQ
Fluoro-silicone
aka FVMQ
Temperatures up to 500 F
hot tear resistance  BAD
Typical Uses  external environments UV resistance, and medical
Other   difficult to inflate without tearing for tool release
More Detail http://www.dowcorning.com/content/rubber/silicone-
rubber.aspx
 
Thiocol TM
Generic "PolySulfide"
aka "T" "ST"
Temperatures  Good for ultra low
tear resistance  poor, suffers compression set
Typical Uses   Solvents, rocket fuel seals
Other  Difficulties with mold (mould) release.
More detail
http://www.britannica.com/EBchecked/topic/469125/polysulfide-rubber
 
====================================================================
 
GENERAL COMPARISONS
http://www.ashtabularubber.com/elastomerselection-page.html
GENERAL NOTE - CAVEAT  A typical elastomer compound may have at
least :-
The named Elastomer, an activator, an accelerator, the curing -
cross linking agent ,
a plasticizer (PREFERABLY cross-linking) anti ozonant, fillers
typically chimney /
furnace black, etc . Up to a dozen constituents.
The performance of any one of the above available synthetic
"rubbers" depends on
the experience of the compound formulator and a full disclosure by
the end user of
all the details of the actual application.
 
=================================================================
NON ELASTOMERS - IE "PLASTOMERS".
 
"Flexflon" TM
aka LDI "DW series"
PTFE that has been raised to 730 F gell temperature
converting all PTFE sintered prcipitate particles
into one homogeneous plastic.
Imparts some resilience and enable flexibility when
combined with concentric wave shaped corrugations.
Servicability as PTFE
Availability membranes up to 305mm diameter, 320 in3
5.25 Liter .
 
Virgin PTFE,
aka LDI "DF series"
has bonded high temp EPT backing to provide some resilience -
to impede the "cold flow" of PTFE.  and slow the rate of
permeation experienced with virgin PTFE (aka "Teflon" TM) because
of its sintered particulate nature.
Availability  Membranes up to 454mm diameter, 1000 in3
16.4 liter .
 

Trade names / trade marks,  noted here in "TM"  are the property of
their respective technology owners. Predominantly "Dupont Dow Elastomers"

 

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