Parker O-ring Division The High Performance Leader.

Parker O-ring Division

Parker O-ring Division

The High Performance

Leader

Material Technolog

y

Material Technolog

y

The Chemistry of Elastomers

Rubber TechnologyRubber Technology

“Rubber” compounds are resilient (elastic) materials made from one or more cross-linked base polymers, reinforcing agents, processing aids, and performance-enhancing additives. Compounds are tweaked for performance variations by adding other ingredients to the base polymer.

Polymers – Basic InformationPolymers – Basic Information

Base polymer determines chemical resistance, rough temperature limits, and rebound resilience. Also provides “baseline” for abrasion resistance, compression set resistance, permeability.

Polymer chains must be “glued” together (cross-linked) to achieve resilience and elasticity. Typical curing systems are Sulfur, Organic Peroxides, and Bisphenol.

Compounding - FillersCompounding - Fillers

Fillers are reinforcing agents that add mechanical strength and resistance to abrasion, permeation, and compression set Carbon black: standard for black

compounds Silica: standard for non-black compounds

Pasticizers are oils and/or polymers used to lower the low temp limit of Nitrile and make the material flow better

O-ring materials used at Kimray

O-ring materials used at Kimray

Nitrile (NBR) BunaHydrogenated

Nitrile (HNBR) HSNEthylene-Propylene

(EPR, EP, EPDM)Polyurethane (AU,

EU)

Fluorocarbon (FKM) Viton®

Tetrafluoroethylene-Propylene (TFE/P) Aflas®

Perfluoroelastomer (FFKM) Kalrez®, Chemraz®, Parofluor®

Standard MaterialsStandard Materials

Fluorocarbon (FKM) VITON®

-15° F to + 400° F V1164-75Fluorocarbon (FKM) VITON®

-15° F to + 400° F V1164-75

Recommended For Petroleum oils Silicone fluids Acids (Black ONLY) Aromatic solvents Halogenated

hydrocarbons Air

Not Recommended For Ketones Steam and hot water Amines Low temperature Automotive brake

fluid Aircraft brake fluid

Nitrile (NBR) Buna -40° F to 250° F N0674-70

Nitrile (NBR) Buna -40° F to 250° F N0674-70 Recommended for:

Aliphatic hydrocarbons (propane, butane, petroleum oil, mineral oil and grease, diesel fuel, fuel oils) vegetable and mineral oils and greases.

Dilute acids, alkali and salt solutions at low temperatures.

Water (special compounds up to 100°C) (212°F).

Not recommended for: Fuels of high aromatic

content (for flex fuels a special compound must be used).

Aromatic hydrocarbons (benzene).

Chlorinated hydrocarbons (trichlorethylene).

Polar solvents (ketone, acetone, acetic acid, ethyleneester).

Strong acids. Brake fluid with glycol

base. Ozone, weather and

atmospheric aging.

Hydrogenated Nitriles (HSN, HNBR) -25° F to 300/325° F

Hydrogenated Nitriles (HSN, HNBR) -25° F to 300/325° F Recommended for:

Well service Improved methanol

and sour gas resistance over nitrile

High temperature resistance relative to Nitrile

Petroleum oils Water/Steam Dilute acids and bases Aliphatic hydrocarbons Ozone

Not recommended for: Polar solvents

(methanol and ketones)

Strong acids Fuels Chlorinated

hydrocarbons Acetone Aldehydes

N4007-95, KB163-90, N1231-80, N1173-70

SpecialMaterialsSpecial

Materials

Ethylene Propylene

(EPDM, EP, EPR)

Ethylene Propylene

(EPDM, EP, EPR)

Ethylene –Propylene (EPDM, EPR) -60° F to + 250° E0962-90

Ethylene –Propylene (EPDM, EPR) -60° F to + 250° E0962-90Recommended for

Geothermal Steam service

(500°F) Explosive

decompression Steam/oil mixtures

of less than 10% petroleum fluid

Not Recommended for Mineral oil

productsE0962-90 is unique in that is can withstand continous steam applications at 500°F

Highly Saturated

Nitrile (HSN, HNBR)

Highly Saturated

Nitrile (HSN, HNBR)

Low Temperature HNBR -58° F to + 300° F KA183-85

Low Temperature HNBR -58° F to + 300° F KA183-85

Wide temperature range: Excellent abrasion resistance Excellent wear resistance Good extrusion resistance

Extensive testing profile for EOG-specific requirements which include testing in: Methanol Oil Marston Bentley’s oceanic fluids Kerosene Baroid’s Petrofree drilling fluid

Fluorocarbon (FKM)

Fluorocarbon (FKM)

Low Temp Fluorocarbon(FKM)-55° F to + 400° F V1289-75

Low Temp Fluorocarbon(FKM)-55° F to + 400° F V1289-75

Compared to GLT FKM: Better low temperature

rating than GLT FKM Lower volume swell than

than GLT FKM Compared to GFLT FKM:

Better low temperature rating than GFLT FKM

Better compression set than GFLT FKM

Compared to standard FKM Better low temperature

rating than standard FKM Lower volume swell than

standard FKM Compared to low

temperature Nitrile Better compression set

than Nitrile Lower swell than Nitrile No dry-out shrinkage Better high temperature

rating than Nitrile

V1289-75 has significant advantages compared

with other elastomeric seal materials:

Sour Gas Service FKM+10° F to + 400° F VP104-85

Sour Gas Service FKM+10° F to + 400° F VP104-85VP104-85 has significant advantages for the Energy, Oil and Gas industry compared

with other elastomeric seal

materials Compared to standard A-

type FKM Better explosive decompression

resistance in sour gas Better amine resistance Better base resistance Better methanol resistance Better steam / hot water

resistance Compared to FFKM

Better explosive decompression resistance in sour gas

Lower cost

Compared to HNBR Better ED resistance Better steam/hot water

resistance Better acid/base

resistance Better high temperature

performance Compared to high-

temperature HNBR Better explosive

decompression resistance in sour gas

Better steam/hot water resistance

Better acid/base resistance

Better high temperature performance

ETP Fluorocarbon (FKM)-15° F to + 400° F V1260-75

ETP Fluorocarbon (FKM)-15° F to + 400° F V1260-75

Increased Chemical Compatibility Practically everything Polar and Aromatic

solvents

Not Recommended For Refrigerant gases Low cost

applications Low temperatures

Polymer trade name is Viton® Extreme – similar performance to Hifluor®, but usually a lot less expensive.

Explossive Decompression Resistant 15°F to +400°FFKM V1238-95

Explossive Decompression Resistant 15°F to +400°FFKM V1238-95

95 Shore A Durometer Fluorocarbon. Developed for maximum extrusion

resistance, good compression set resistance.

ED ResistantApplications: High temperature, high-

pressure H2S.

FFKM HIFLUOR ®

TFE/P

FFKM HIFLUOR ®

TFE/P

Specialty Compounds

Parofluor ULTRA(FFKM) +5° F to + 600° F

Parofluor ULTRA(FFKM) +5° F to + 600° F

Recommended For Down hole (sour gas) Drilling mud Amine-based fluids Steam and other

aggressive fluids High temperature

applications

Not Recommended For Refrigerant gases Low cost

applications Low temperatures

FF200-75 FF500-75 FF202-90

Competes directly with Kalrez ® and Chemraz. ® The best of the best.

Chemical Family FF500-75 FF200-75 Kalrez® 4079

Organic Acids 1 1 1

Inorganic Acids 1 1 1

Bases 1 2 3

Amines 1 3 4

Steam/ Hot Water 1 2 3

Ketones 1 1 1

Aldehydes 1 2 4

FFKMChemical Resistance Properties

FFKMChemical Resistance Properties

Hifluor ® (FKM) -15° F to + 400° F

Hifluor ® (FKM) -15° F to + 400° F

Recommended For Down hole (sour gas) Drilling mud Amine-based fluids Steam and other

aggressive fluids

Not Recommended For Refrigerant gases Low cost applications Low temperatures

V3819-75 V8534-90

Similar chemical properties as Parofluor but about 20% less expensive.

Aflas® (TFE/P) +15° F to + 450° F

Aflas® (TFE/P) +15° F to + 450° F

Recommended For Petroleum oils Alcohols Silicone fluids Sour gas Amines Air Steam / hot water

Not Recommended For Low temperature Gasoline

V1041-80 VP101-80 VP103-90

Poor compression set – primarily used in chemical plants.

ExplosiveDecompressi

onMaterials

ExplosiveDecompressi

onMaterials

Explosive Decompression Resistant CompoundsExplosive Decompression Resistant Compounds

N1231-80 (HNBR)E0962-90 (EPDM)- VP103-90 (Aflas®)-V1238-95 (FKM, Viton®)-V8534-90 (HiFluor®)-V8588-90 (Parofluor®, FFKM, Kalrez®)-FF202-90 (Parofluor Ultra®, FFKM,

Kalrez®)-

Failure ModesFailure Modes

Maximizing life through failure

diagnosis

Common reasons for O-Ring failure(Often an O-Ring fails from a combination of problems)

Common reasons for O-Ring failure(Often an O-Ring fails from a combination of problems)

Abrasion Chemical attack Compression set Cracks in Nitrile rubber Exceeding material temperature

limits Explosive Decompression Extrusion and/or nibbling Installation Damage Overfill Spiral failure

AbrasionAbrasion

Looks like the seal is sanded off or flattened on one side of the o-ring.

Causes: Poor surface finish O-Ring passes over ports Use of non abrasion resistant material Excessive swell and softening No lubrication

AbrasionAbrasion

Solutions: Check finish and smooth if necessary Use a lubricant or internally lubricated

material Use a material that resists wear Use a lower swell material

Chemical AttackChemical Attack

The seal swells a lot, shrinks, loses physical properties. Excessive swell, brittleness, and

dramatic loss in physical properties. Find a compatible base polymer.

Shrinkage: the fluid is probably extracting something from the rubber.



Solutions: Use material compatible with all

fluids. Determine percentage of all fluids in the stream.

Find a compatible base polymer. Determine compound by chemical analysis and reviewing MSDS.

Change compounds (changing the base polymer isn’t always required.)

Compression SetCompression Set

O-Ring Conforms to shape of groove

Looks like the seal has been flattened or deformed.

Causes: Happens whenever rubber is

compressed -- is accelerated by:o excessive or insufficient

squeezeo high temperatureso Chemical attack due to

incompatible fluids.

Compression Set = amount of loss / initial deformation

Compression Set = (HI – HR)/ (HI – HC)

Compression Set = (.100 - .090) / (.100 - .075)Compression Set = (.010) / (.025 ) = .40Compression Set = 40%

HIHC HR




Solutions: Evaluate gland dimensions

ocheck for proper squeezeoconsider tolerancesoconsider ID stretch and cross section reduction

Evaluate materialocheck for compatibility with fluids and

temperatureouse set resistant compound

Evenly spaced radial cracking around the circumference of the O-Ring (typically Nitrile) -- especially where it’s stretched.

Causes: Ozone, UV light, Fluorescent light,

Electric motors. There is ozone in the air around us, and this can be enough to destroy an O-Ring.

Cracks in Nitrile RubberCracks in Nitrile Rubber



Solutions: Coat o-rings with a silicone or

petroleum lubricant Choose a base polymer that is

naturally resistant to ozone


Low Temperature FailureLow Temperature Failure

Seal leaks at low temperatures only. As seal materials cool to within 15oF of their

minimum operating temperature, they lose resilience. Any movement may allow leakage of low viscosity liquids and gases. Low temperature changes are not permanent and do not damage the seal.

Use a seal material with improved low temperature performance.

High Temperature FailureHigh Temperature Failure

Rubber “melts” or becomes brittle. Every rubber polymer has a temperature

above which it begins to break down. Thermal degradation is permanent and irreversible.

Use a seal material with improved high temperature performance or cool the seal gland area.

Explosive DecompressionExplosive Decompression

Internal or external cracks, ruptures, blisters.

Causes Gasses permeate material and

when system is rapidly decompressed, gas quickly escapes leaving ruptures



Solutions: Slice cross section at blister or rupture

and look for internal fissure to verify explosive decompression is cause

Determine application pressure and decompression rate

Slow decompression rate Use explosive decompression resistant

material Use a more explosive decompression

resistant material such as V1238-95.

Extrusion and NibblingExtrusion and Nibbling

Looks like one side of the seal is chewed off.

Is caused by high pressure “pushing” the O-Ring into a gap between the metal surfaces.

Causes. High pressure Excessive clearance Excessive swelling and softening






Solutions Evaluate gland design

oUse InPHorm or extrusion chart to determine pressure rating

o If gland can be widened, use backup ring

Evaluate materialoUse higher pressure materialoUse material compatible with the

environmentoUse extrusion resistant compound

if necessary

Installation DamageInstallation Damage

Sheared, torn, nicked cut appearance

Causes: sliding over threads insufficient chamfer improper size no lubrication



Solutions: cover threads during installation use lubrication chamfer and smooth edges use correct size

OverfillOverfill

Appears similar to extrusion, but nibbling is on both sides, or O-Ring takes set with visible ridge over groove edge.

Causes Insufficient void space in groove Excessive swell in system fluids Improper size O-Ring

OverfillOverfill

Solutions: Use proper groove width Use lower swell material Use smaller cross section if squeeze

is not reduced below recommended minimum

Spiral FailureSpiral Failure

Looks like a split wrapping around the ring.

Causes: Happens when the seal on a piston or

rod “grips” instead of slides in one spot (common with long, slow strokes).

Can happen on static seals with pressure cycling.

ID to CS aspect ratio, reciprocating Installation damage Soft material No lubrication

Spiral FailureSpiral Failure

Spiral FailureSpiral Failure Solutions:

Can be prevented by using a smoother surface, lubricating uniformly, using a stiffer rubber compound, or using an engineered seal.

Use proper cross section for inside diameter to provide stability in groove for reciprocating seal

Use a lubricant or internally lubricated material

evaluate surface finish, chamfer, sharp edges

Use different cross section shape to provide stability in groove

QuestionsQuestions

Parker O-ring Division The High Performance Leader.

Documents

f v1164

f n0674

v aromatic solvents

v carbon black

ketones v steam

petroleum fluid f

f polymer chains

black compounds v silica