Viton Properties

7/28/2019 Viton Properties

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Seals Eastern has been successfully designing and installing mission critical seals

molded of formulated Viton since 1960.

Seals Eastern was one of the earliest companies to develop applications using Viton polymers

by DuPont Dow Elastomers. Seals Eastern precision molds all grades of Viton polymers into o-

rings, gaskets, and other seals. Generally speaking, products molded using Viton elastomersprovide exceptional resistance to heat, oils, and chemicals.

Seals Eastern's formulated Viton elastomers can be applied in many seal designs andapplications.

D1418Class

Duro Compound Description

FKM

Type 1 60 5722A66% Fluorine (F) copolymer. Excellent mechanicalproperties. Good extrusion resistance. Chemical andheat resistant.

75 7040 66% F copolymer. Chemical and heat resistant.

85 7042U66% Fluorine (F) copolymer. Excellent mechanicalproperties. Good extrusion resistance. Chemical andheat resistant.

90 7042 66% F copolymer. Chemical and heat resistant.

Type 2 60 572268% F terpolymer. Maximum retention of elasticproperties. Excellent resistance to fluids and heataging.

70 5787 69% F terpolymer. Exceptional resistance to oils,organic fluids, steam, inorganic acids and otheraqueous media.

75 572368% F terpolymer. Maximum retention of elasticproperties. Excellent resistance to fluids and heataging.

85 572468% F terpolymer. Maximum retention of elasticproperties. Excellent resistance to fluids and heataging.

95 572568% F terpolymer. Maximum retention of elasticproperties. Excellent resistance to fluids and heat

aging.FEPM

85 7265Viton Extreme. PMVE/TFE/E composition. Excellentbase resistance.

Most Viton elastomers are categorized under the ASTM D1418 designation of FKM.

This class of elastomer is further categorized by types.
http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5722Ahttp://www.sealseastern.com/CompoundSpec.asp?cmpnd=7040http://www.sealseastern.com/CompoundSpec.asp?cmpnd=7042Uhttp://www.sealseastern.com/CompoundSpec.asp?cmpnd=7042http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5722http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5787http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5723http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5724http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5725http://www.sealseastern.com/CompoundSpec.asp?cmpnd=7265http://www.sealseastern.com/CompoundSpec.asp?cmpnd=7040http://www.sealseastern.com/CompoundSpec.asp?cmpnd=7042Uhttp://www.sealseastern.com/CompoundSpec.asp?cmpnd=7042http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5722http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5787http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5723http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5724http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5725http://www.sealseastern.com/CompoundSpec.asp?cmpnd=7265http://www.sealseastern.com/CompoundSpec.asp?cmpnd=5722A


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Type-1 FKM: is a copolymer of hexafluoropropylene (HFP) and vinylidene

fluoride (VDF or VF2).

Type-2 FKM: is a terpolymer of tetrafluoroethylene (TFE), vinylidene fluoride

(VDF), and hexafluoropropylene (HFP).

On account of these molecular compositions, Viton based elastomer formulations delivera broad range of chemical resistance, continuous service temperatures of 350F, and low

temperature capabilities down to 10F.

Viton-ETP , also referred to as "Extreme", is an FEPM class material, additionally offers

excellent base resistance since there is no vinylidene fluoride in the composition.

Do not be fooled by cheap Viton o-rings that often contain reground material, cheap

fluorocarbon copolymers and will deliver inferior performance. Seals Eastern guaranteesits Viton formulated seals are made using 100% virgin Viton polymers and are

post-cured in accordance with DuPont Dow recommendation.

To learn more about Viton Viton is a registered trademark of DuPont

Technical InfoVitonconsists of essentially four different "families" of polymers:

VitonFamily

Product Types Principal End Users Polymer CompositionWeight%Fluorine

A A, ALGeneral purpose sealing:

Automotive, Aerospace fuels& lubricants

Dipolymers of VF2/HFP ~67%

B B, BL, GBLChemical Process plant,Power Utility Seals & Gaskets

Terpolymers ofVF2/HFP/TFE

~68%

F F, GFOxygenated Automotive fuels.Concentrated aqueousinorganic acids, water, steam

Terpolymers ofVF2/HFP/TFE

~69%

BR

IBR, TBR, ETP

(New base-resistanttypes are underdevelopment.)

Automotive & Off-Road -High pH lubricants, greases,& Coolants.Oil Exploration/Production -Drilling Muds, Sour Wells.Special sealingrequirements - solvents,coatings, ultra harshenvironments (ETP)

Copolymers of

TFE/Propylene,TFE/Propylene/VF2,Ethylene/TFE/PMVE

~60-65%

The four families differ primarily in the end-use performance of parts made from Viton. Each
http://www.viton.com/Products/Viton/techInfo.asphttp://www.viton.com/Products/Viton/techInfo.asp


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family differs in its ability to: resist permeation and volume increase, resist attack andproperty degradation caused by the chemicals and fluids.

Speciality versions of A,B & F types are available in which HFP is replaced with a specialitymonomer to improve low temperature flexibility. These are called LT types, for example,

GLT, GBLT, and GFLT, and they perform like the A, B, and F families, respectively.

The choice of the most appropriate "family" of Viton to use for any given end-use applicationwill be determined by the end-use service, and in particular, whether the finished part mustprovide:

Resistance to amines or caustics

Resistance to hydrocarbon fluids

Flexibility at low temperature (ability to maintain a seal at low temperature)

The end-use performance capability of the various families of Viton differ primarily in terms ofthese three factors.

End-use service differences between Viton types

Standardand

SpecialityTypes

LowTemp.

FlexibilityTR-10,

C

CompressionSet, O-rings70 h/200C,

%

Fluid Resistance Base Resistance

% Volume Increase after 168 h% loss of elongation at

break

Tolueneat 40C

FuelC/MeOH(85/15)at 23C

Methanolat 23C

ConcentratedH2SO4 at

70C

33%solution of

KOH336h/40C

ASTM Ref.Oil 105

500h/150C

AL -19 20-25 20-25 35-40 85-95 12-15 -50 -80A -17 12-17 20-25 35-40 85-95 10-12 -45 -80

BL, GBL -15 25-40 12-15 20-25 25-35 3-5 -25 -65

B -13 25-30 12-15 18-23 25-35 8-10 -25 -70

ETP -11 45-50 6-8 8-10 1-2 4-6 0 -10

GFLT -24 35-40 8-12 10-15 3-5 3-5 -30 -40

GBLT -26 35-40 12-15 27-32 25-35 3-5 -40 -50

F -8 30-45 8-12 5-10 3-5 7-9 -50 -55

GF -8 30-45 8-12 5-10 3-5 7-9 -45 -50

TBR +3 45-50 60-65 80-90 - 3-5 -10 -20

IBR -6 45-50 50-55 70-80 - 7-9 -25 -40


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PTFESPECIFICATIONS

TechnicalDescription

Discovered in 1938 by Dr. Roy J. Plunkett of the DuPont Company, PTFE is afluorocarbon-based polymer. PolyTetraFluoroEthylene is commonly abbreviated

PTFE, and the PTFE brand of PTFE is manufactured only by DuPont. the fluoroplastic

family offers plastics with high chemical

resistance, low and high temperature

capabiltiy, resistance to weathering, low

friction, electrical and thermal insulation, and

"slipperiness".

General Properties

PTFE mechanical properties are low

compared to other plastics, but its properties

remain at a useful level over a wide

temperature range of -100F to +400F (-73C to 204C). Mechanical properties are

often enhanced by adding fillers (see filled grades below). It has excellent thermal and

electrical insulation properties and a low coefficient of friction. PTFE is very dense and

cannot be melt processed - it must be compressed and sintered to form useful shapes.

Filled Grades

PTFE's mechanical properties can be enhanced by adding fillers such as glass fibers,

carbon, graphite, molybdenum disulphide, and bronze. Generally, filled PTFE's

maintain their excellent chemical and high temperature characteristics, while fillers

improve mechanical strength, stability, and wear resistance. The properties of 25%

glass-filled PTFE grade are shown below. There are literally dozens of different filled

PTFE products and grades - too many to be listed here. Please contact EPM for more

information about other filled PTFE products for your application.

TYPICALPROPERTIESof PTFE

ASTMor UL test PropertyPTFE

(unfilled)

PTFE

(25%glassfilled)

PHYSICAL

D792Density (lb/in?)

(g/cm?)

0.079

2.2

0.081

2.24

D570 Water Absorption, 24 hrs (%) < 0.01 0.02

MECHANICAL


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D638 Tensile Strength (psi) 6,000 2,700

D638 Tensile Modulus (psi) 80,000 -

D638 Tensile Elongation at Break (%) 300 270

D790 Flexural Strength (psi) No break 1,800

D790 Flexural Modulus (psi) 27,000 19,000D695 Compressive Strength (psi) 3,500 1,500

D695 Compressive Modulus (psi) 70,000 110,000

D785 Hardness, Shore D D50-65 D54

D256 IZOD Notched Impact (ft-lb/in) 3.5 2.0

THERMAL

D696Coefficient of Linear Thermal Expansion

(x 10-5 in./in./F)7.5 5.0

D648Heat Deflection Temp (F / C)

at 264 psi 132 / 55 150 / 65

D3418 Melting Temp (F / C) 635 / 335 635 / 335

- Max Operating Temp (F / C) 500 / 260 500 / 260

C177

Thermal Conductivity

(BTU-in/ft?-hr-F)

(x 10-4 cal/cm-sec-C)

1.70

5.86

3.1

10.6

UL94 Flammability Rating V-O V-O

ELECTRICAL

D149Dielectric Strength (V/mil) short time, 1/8"

thick285 -

D150 Dielectric Constant at 1 MHz 2.1 2.4D150 Dissipation Factor at 1 MHz < 0.0002 0.05

D257 Volume Resistivity (ohm-cm)at 50% RH > 1018 > 1015

Note: The information contained herein are typical values intended for reference and

comparison purposes only. They should not be used as basis for design specifications or

quality control. Contact us for manufacturers' complete material property datasheets. All values

at 73F (23C unless otherwise noted.

PTFE is a registered trademark of DuPont


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FrequentlyAskedQuestions

QUESTION 1: Can you give me the general characteristics and properties of commonly used seals

materials ?

QUESTION 2: Pump and Motor Conditions of a Hydraulic CylinderQUESTION 3: Hydraulic Fluid Monitoring Requirements?

QUESTION 4: Why should I use a scraper or wiper ring?

QUESTION 5: Correcting Seal Failures

QUESTION 6: Can you give me some information on the "Basic Theory" of how hydraulics work?

QUESTION 7: How does a "static" seal work?

QUESTION 8: What are some of the challenges of a dynamic seal?

QUESTION 9: Tell me about rotary seals and how they work?

QUESTION 10: On a hydraulic cylinder, what should I look for and what area should I be concerned

about for its proper performance?

QUESTION 11: Can you make and ship seals the same day?QUESTION 12: How do you make seals?

QUESTION 13: How large in diameter can you manufacture?

QUESTION 14: How do I know what delivery services are available for a product?

QUESTION 1: Can you give me the general characteristics and properties of commonly used seals

materials?

ANSWER: ETHYLENE PROPYLENE RUBBER (EPM, EPDM, EPR):

This elastomer is a copolymer of ethylene and propylene and is sometimes compounded with a third

monomer (EPT). Good to excellent compression set resistance is obtained by the addition of peroxidecures during vulcanisation. Ethylene propylene materials have excellent resistance to phosphate esters

such as Skydrol, Fyrquel, Pydraul, water and steam, acids, alkali, salt solutions, ketones, alcohol's,

glycol's, and silicone oils and greases. EPR has very poor resistance to petroleum oils and diester-base

lubricants. Ethylene propylene is a close contender to Buna-N and butyl in the important sealing

properties, except that it does not have the petroleum oil and fuel resistance of Buna-N, nor the low-gas-

permeability quality of butyl.

NITRILE OR BUNA-N RUBBER: More nitrile seals are used than all the other elastomers combined,

since nitrile is the most versatile material. Nitriles are a copolymer of acrylonitrile and butadiene. As the

acrylonitrile content of nitriles increases, the oil and fuel resistance increases while the low-temperature

flexibility decreases. Nitrile-based elastomers are usually specified by military MS and AN O-rings when

used in oil and fuel applications, but because nitrile compounds vary widely within such a large overalltemperature range, particular attention should be paid to specifying physical properties. Materials can be

formulated to perform satisfactorily over the temperature range 65 to +300 degrees F, so it is necessary

to make sure that the particular nitrile chosen meets the temperature requirements of the application.

The nitrile materials are recommended for general-purpose sealing of alkaline and salt solutions,

petroleum oils and fluids, vegetable and diester oils, silicone greases and oils, ethylene glycol-base

fluids, alcohol's, gasoline's and water. They are not suited for use with strong oxidising agents;

chlorinated solvents such as carbon tetrachloride or trichlorethylene, nitrated hydro-carbons such as

nitrobenzene or aniline; ketones such as methyl ethyl ketone (MEK) and acetone; and aromatic

hydrocarbons. Ozone will usually attack nitrile materials, but resistance can be greatly improved by the
http://www.epm.com/faq.html#QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?%23QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?http://www.epm.com/faq.html#QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?%23QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?http://www.epm.com/faq.html#QUESTION%202:%20Pump%20and%20Motor%20Conditions%20of%20a%20Hydraulic%20Cylinder%23QUESTION%202:%20Pump%20and%20Motor%20Conditions%20of%20a%20Hydraulic%20Cylinderhttp://www.epm.com/faq.html#QUESTION%203:%20Hydraulic%20Fluid%20Monitoring%20Requirements?%23QUESTION%203:%20Hydraulic%20Fluid%20Monitoring%20Requirements?http://www.epm.com/faq.html#QUESTION%204:%20Why%20should%20I%20use%20a%20scraper%20or%20wiper%20ring?%23QUESTION%204:%20Why%20should%20I%20use%20a%20scraper%20or%20wiper%20ring?http://www.epm.com/faq.html#QUESTION%205:%20Correcting%20Seal%20Failures%23QUESTION%205:%20Correcting%20Seal%20Failureshttp://www.epm.com/faq.html#QUESTION%206:%20Can%20you%20give%20me%20some%20information%20on%20the%20http://www.epm.com/faq.html#QUESTION%207:%20How%20does%20a%20http://www.epm.com/faq.html#QUESTION%208:%20What%20are%20some%20of%20the%20challenges%20of%20a%20dynamic%20seal?%23QUESTION%208:%20What%20are%20some%20of%20the%20challenges%20of%20a%20dynamic%20seal?http://www.epm.com/faq.html#QUESTION%209:%20Tell%20me%20about%20rotary%20seals%20and%20how%20they%20work?%23QUESTION%209:%20Tell%20me%20about%20rotary%20seals%20and%20how%20they%20work?http://www.epm.com/faq.html#Question%2010:%20On%20a%20hydraulic%20cylinder,%20what%20should%20I%20look%20for%20and%20what%20area%20should%20I%20be%20concerned%20about%20for%20its%20proper%20performance?%23Question%2010:%20On%20a%20hydraulic%20cylinder,%20what%20should%20I%20look%20for%20and%20what%20area%20should%20I%20be%20concernedhttp://www.epm.com/faq.html#Question%2010:%20On%20a%20hydraulic%20cylinder,%20what%20should%20I%20look%20for%20and%20what%20area%20should%20I%20be%20concerned%20about%20for%20its%20proper%20performance?%23Question%2010:%20On%20a%20hydraulic%20cylinder,%20what%20should%20I%20look%20for%20and%20what%20area%20should%20I%20be%20concernedhttp://www.epm.com/faq.html#QUESTION%2011:%20Can%20you%20make%20and%20ship%20seals%20the%20same%20day?%23QUESTION%2011:%20Can%20you%20make%20and%20ship%20seals%20the%20same%20day?http://www.epm.com/faq.html#QUESTION%2012:%20How%20do%20you%20make%20seals?%23QUESTION%2012:%20How%20do%20you%20make%20seals?http://www.epm.com/faq.html#QUESTION%2013:%20How%20large%20in%20diameter%20can%20you%20manufacture?%23QUESTION%2013:%20How%20large%20in%20diameter%20can%20you%20manufacture?http://www.epm.com/faq.html#Anchor-QUESTION-49575%23Anchor-QUESTION-49575http://www.epm.com/faq.html#QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?%23QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?http://www.epm.com/faq.html#QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?%23QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?http://www.epm.com/faq.html#QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?%23QUESTION%201:%20Can%20you%20give%20me%20the%20general%20characteristics%20and%20properties%20of%20commonly%20used%20seals%20materials?http://www.epm.com/faq.html#QUESTION%202:%20Pump%20and%20Motor%20Conditions%20of%20a%20Hydraulic%20Cylinder%23QUESTION%202:%20Pump%20and%20Motor%20Conditions%20of%20a%20Hydraulic%20Cylinderhttp://www.epm.com/faq.html#QUESTION%203:%20Hydraulic%20Fluid%20Monitoring%20Requirements?%23QUESTION%203:%20Hydraulic%20Fluid%20Monitoring%20Requirements?http://www.epm.com/faq.html#QUESTION%204:%20Why%20should%20I%20use%20a%20scraper%20or%20wiper%20ring?%23QUESTION%204:%20Why%20should%20I%20use%20a%20scraper%20or%20wiper%20ring?http://www.epm.com/faq.html#QUESTION%205:%20Correcting%20Seal%20Failures%23QUESTION%205:%20Correcting%20Seal%20Failureshttp://www.epm.com/faq.html#QUESTION%206:%20Can%20you%20give%20me%20some%20information%20on%20the%20http://www.epm.com/faq.html#QUESTION%207:%20How%20does%20a%20http://www.epm.com/faq.html#QUESTION%208:%20What%20are%20some%20of%20the%20challenges%20of%20a%20dynamic%20seal?%23QUESTION%208:%20What%20are%20some%20of%20the%20challenges%20of%20a%20dynamic%20seal?http://www.epm.com/faq.html#QUESTION%209:%20Tell%20me%20about%20rotary%20seals%20and%20how%20they%20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addition of antioxidant compounds.

FLUOROCARBON RUBBER (FKM): Fluorocarbon elastomers have been compounded to meet a wide

range of chemical and physical requirements. Under the trade name Viton, Fluorel, and Kel-F and

fluorocarbons seals have been employed where other materials cannot survive severe chemical

conditions. The working temperature range of FKM is between -20 and +400 degrees F (-29 and +204

degrees C) and limited temperature spikes of 600 degrees F have been incurred. New compounds havegreatly improved the compression set of fluorocarbon O-ring seals.

SILICONE RUBBER (Si): Silicone elastomers are compounded from dimethyl silicone polymers, and

thus will deteriorate if used with silicone oils and greases. Various additives have extended the functional

temperature range of silicone rubber beyond any other elastomer. Flexibility below -175 degrees F (-114

degrees C) and service above 700 degrees F (371 degrees C) for short periods of time have been

demonstrated. High production cost have normally limited the use of silicone seals to applications

requiring extreme temperature resistance. Production molding of silicone seals involves high-

temperature secondary cure which results in greater than normal shrinkage. The finished O-ring seal is

usually undersized when produced in standard moulds. The designer should be aware of this size

difference when designing glands for silicone O-rings. Silicone elastomer have poor resistance to ketone

solvents such as MEK and acetone, and poor resistance to most petroleum fluids. They have very poorphysical properties that make them unattractive for dynamic applications. Silicone seals are

recommended for extreme temperature use with ozone, oxygen, high-aniline point oils, and chlorinated

diphenyls.

POLYURETHANE (AU, EU): Polyurethane elastomers are compounds of polyethers and diisocryanates.

These materials have excellent physical properties of abrasion resistance and tensile strength, which

make them outstanding for dynamic applications. They have excellent resistance to weather, ozone, and

oxygen, good resistance to hydrocarbon fuels, petroleum oils, and aliphatic solvents and fair resistance

to aromatic hydrocarbons. Acids, ketones, and chlorinated hydrocarbons attack and deteriorate

polyurethane. Because polyurethane is available in castable liquids, injection-mouldable pellets and

millable gums, it is a very useful material for specialised sealing problems.

QUESTION 2: Pump and Motor Conditions of a Hydraulic Cylinder

In any high pressure seal, the tendency for the fluid pressure to extrude the seal into the clearance gap

is a major cause of failure. In seals for reciprocating applications, friction between the seal and the wall

against which it moves may either augment this effect or oppose it. These circumstances are usually

called pump condition and motor condition respectively, since they are found in piston seals on these

machines.

Seal performance is likely to be better in motor condition. Often, it is possible at the design stage to

arrange for seals to be working in this condition. If so, this should certainly be done, but remember that if

it results in the seal having to operate within a bore, this cannot usually be given such a high finish, or be

made to such close tolerance, as an external surface.

The condition of lubrication between the seal and the surface against which it slides vary from boundary

to thick film lubrication, depending on the viscosity of the fluid, sliding speed and the pressure. With film

lubrication normally arising from a combination of viscous fluid, high speed and, perhaps also, low

pressure, the amount of fluid left behind a seal as it moves may be considerable. In the pump condition

this may be termed leakage, but on the motoring stroke a similar effect may occur if the shaft remains

wetted by the fluid, in spite of the fact that this then means that fluid is being moved from a low to a high

pressure, that is, negative leakage. It should be noted that negative leakage may result in air ingress,


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and thus attempts to obtain zero leakage may result in aeration of the fluid to be sealed.

QUESTION 3: Hydraulic Fluid Monitoring Requirements?

Antiwear Water Phosphate Oil/Synthetic Water-in-oil Oil & Water Petroleum glycol ester Blend Emulsion Emulsion

Oil (Invert) (soluble oil)

Viscosity pH, emulsion

Neutralisation Water Stability

number content Oil

Moisture pH Emulsion

Specific Stability

Gravity

Fungi

HYDRAULIC FLUID MAINTENANCE

Fluid and equipment should be maintained properly even before the installation of the fluids. All fluids

should be stored inside sealed containers, or under a roof and on their sides to minimise entry of water

and dirt. Caps and drums tops should be cleaned thoroughly before opening. Only clean hoses and

containers should be utilised to transfer fluids from cans, drums or bulk storage areas to hydraulic

reservoirs. These hoses should be equipped with proper filtration devices. The reservoir to which the

fluid is to be placed should also contain a mesh screen on its filler pipe.

The installation of the fluid itself should be done properly and correctly and to clean equipment. Use only

the type and grade hydraulic fluid recommended by the hydraulic equipment manufacturer or by the fluid

supplier. Different types of hydraulic fluids should not be mixed. Before installing the hydraulic fluid, the

system should be flushed and cleaned exactly as recommended by the manufacturer. All hydraulic filtersand air breathers should be checked before fill ing. The hydraulic system itself should be thoroughly

checked to eliminate leaks or entry points for contaminants. The equipment should them be filled to the

proper level. Once the system is filled proper maintenance and monitoring should be carried out

throughout the life of both the fluid and equipment in question.

The fluid should be replaced at recommended drain intervals and the system should be drained when it

is warm and has just been circulated so that the maximum amount of contaminant is removed Proper

maintenance of the hydraulic system includes replacing filters and air breathers at recommended

intervals and training operators to service the equipment.

Whether replacing hydraulic system components or in the course of general maintenance, cleanliness

should be maintained at all times. The use of quick-disconnect fittings is useful in eliminating

contaminate entry. Fittings should be wiped clean before use and should be covered when not in use.

Proper fluid filtration should be provided to keep contamination levels down. Selection of appropriate

filters and their strategic placement in proper parts of the system is vital in a well maintained system.

Filter size should be checked with manufacturer before installation. Some filters employed today are so

effective there is a chance they will filter out certain additives if proper selection is not maintained.

Filtration and contamination are important aspects of maintenance and are well-documented.

The quality of the fluid in the reservoir and the system is also critical. Insufficient fluid can limit complete

immersion of some components and can allow the air to be drawn into the system. Drawing air into the


10/23

system creates "spongy" cylinder action and can set up pump cavitation conditions which result in high

or catastrophic wear. Therefore, it is important to prevent fluid leakage and to make sure the fluid level is

always full.

The hydraulic fluid itself should be monitored on a periodic basis. Table 1 gives some basic monitoring

requirements for the basis types of hydraulic fluids discussed. Manufacturers recommendations should

be thoroughly followed and a program should be developed to adhere to these recommendations. Fluidshould be drained and replaced as required. Continued use of a fluid that has outlasted its life in the long

run causes costly down time due to equipment outages.

Since hydraulic fluids are increasing in cost, and reclamation procedures have improved greatly, more

and more hydraulic oil users are reclaiming their own hydraulic fluids. If reclaimed fluid is to be utilised,

care must be taken that the fluid has been reclaimed properly and its quality has been put back to its

original state.

QUESTION 4: Why should I use a scraper or wiper ring?

The function of a scraper ring is to prevent dirt particles from entering the components in a hydraulic orpneumatic circuit; cylinders or valves. This helps prevent contamination of the media which will damage

the seal, the surface of the housing and the guide bush.

Bellows provide a complete protection for reciprocating shafts, but they are complicated to produce and

can be easily damaged so their use is restricted to special applications. In most cases a scraper ring

having one-lip made of wear resistant elastomer, is sufficient.It is important to protect the scraping edge

from damage and to have adequate contact with the groove and piston rod diameter.

The lip of the scraper ring is designed to have a pre-load with the piston rod, and this has an influence

on the break-out friction. Together the pre-load and the sharp scraper edge wipes off the oil film passing

the seal.

Scraper rings are made from elastomeric or thermoplastic materials and some have metal case forstiffness. Special designs are available for applications where, compensation for large radial movements

or a stiffer inner lip is required.It is recommended to use scraper rings which are designed to be a tight fit

in the housing.

QUESTION 5: Correcting Seal Failures

When in trouble there is a simple process to follow in correcting any type of seal failure.

A. Re-examine your seal selection process.

B. Examine complete system.

C. Carefully examine failed seal for evidence of:1. Softening or hardening of seal material

2. Dimensional changes in seal

3. Surface tears, scratches, extrusion or other physical damage

4. Obtain sample of system hydraulic fluid.

D. Contact Economos UK Limited. to assist in analysis of failure and recommended solution.

SYSTEM CONTAMINATION is usually caused by external elements such as dirt, grit, mud, dust even

ice and internal contamination from circulating metal chips, break-down products of fluid, hoses or other


11/23

degradable system components. As most external contamination enters the system during rod

retraction, the proper installation of a rod wiper/scraper is the best solution. Internal contamination is

best prevented by a proper filtering of system fluid. Contamination is indicated by scored rod and

cylinder bore surfaces, excessive seal wear and leakage.

SPIRAL FAILURE is often the result of a combination of factors such as basic seal geometry, long stroke

and/or too soft an elastomer. The classic spiral failure usually is found in a simple O-ring type seal butwill sometimes be evident in unsupported lip type seal as well. The use of T-Seals, harder durometer

materials, and seals with rectangular cross-sections will usually solve this problem.

CHEMICAL BREAKDOWN of the seal material is most often the result of incorrect material selection in

the first place, or subsequent change of system fluid. Misapplication or use of non compatible materials

can lead to chemical attack on seal by fluid additives, hydrolysis and oxidation reduction of seal

elements. Chemical breakdown can result in loss of seal lip interface, softening of seal durometer,

excessive swelling or shrinkage.

IMPROPER INSTALLATION is a major cause of seal failure. The three broad areas to be watched

during seal installation are; cleanliness, protecting the seal from nicks and cuts and proper lubrication.

Other problem areas are over tightening of the seal gland where there is an adjustable gland follower or

folding over a seal lip during installation. The solution to these problems is common sense and taking

reasonable care during assembly.

EXTRUSION of the seal element is usually caused by excessive clearances in metal components, high

axial loading, high pressure and use of too low a durometer seal material. Extrusion causes a loss in

seal volume and stability. The prevention of extrusion usually requires a type of seal with built-in anti-

extrusion rings.

HEAT DEGRADATION is to be suspected when the failed seal exhibits a hard, brittle appearance and/or

shows a breaking away of parts of the seal lip or body. Heat degradation results in loss of sealing lip

effectiveness through excessive compression set and/or loss of seal material. Causes of this condition

may be use of incorrect seal material, high dynamic friction, excessive lip loading, no heel clearance and

proximity to outside heat source. Correction of heat degradation problems may involve reducing seal lipinterference, increasing lubrication, change of seal material. In borderline situations consider all upper

temperature limits to be increased by 50 degrees F in dynamic reciprocating seals at the seal interface

due to running friction.

SLIP-STICK is an expression of the differential between the static and dynamic coefficient of friction as it

relates to start-up of a sliding mechanism. Slip-stick occurs when the seal "hangs-up" in the transition

period between static and dynamic modes or there is a variation in the system fluid pressure, or shock

loads cause the piston to jump back to the static mode. The most noticeable result of Slip-Stick is erratic

or jerky movement of the outer rod. Slip-Stick often creates an audible noise and excessive heat and

seal wear can occur.

QUESTION 6: Can you give me some information on the "Basic Theory" of how hydraulics work?

The basis for all hydraulic systems is expressed by Pascals law which states that the pressure exerted

anywhere upon an enclosed liquid is transmitted undiminished, in all directions, to the interior of the

container. This principle allows large forces to be generated with relatively little effort. As il lustrated, a 5

pound force exerted against a 1 inch square area creates an internal pressure of 5 psi. This pressure,

acting against the 10 square inch area develops 50 pounds of force.

In a basic hydraulic circuit, the force is exerted by a cylinder bore size and the pump pressure. (There is


12/23

no force generated unless there is resistance to the movement of the piston). With 1000 psi pump

pressure exerted against a 12 square inch piston area (approximately 4" dia.), a force of 12,000 pounds

is developed by the cylinder. The speed at which the piston will move is dependent upon the flow rate

(gpm) from the pump and the cylinder area. Hence, if pump delivery is 1 gallon per minute (231

cu.in./min.).

The simplest hydraulic circuit consists of a reservoir, pump, relief valve, 3-way directional control valve,single acting cylinder, connectors and lines. This system is used where the cylinder piston is returned by

mechanical force. With the control valve in neutral, pump flow passes through the valve and back to the

reservoir. With the valve shifted, oil is directed to the piston side of the cylinder, causing the piston to

move, extending the rod. If the valve is returned to neutral, the oil is trapped in the cylinder, holding it in

a fixed position, while pump flow is returned to the reservoir. Shifting the valve in the opposite direction

permits the oil to pass through the valve back to the reservoir. The relief valve limits the system pressure

to a pre-set amount. Relief valves are commonly incorporated into the directional valve.

QUESTION 7: How does a "static" seal work?

A static seal is one used in an application that has no movement between mating surfaces, discountingsuch infinitesimal motion as may be caused by pressure and temperature variations, expansion and

contraction, normal wear, and shock and vibration. Examples include seals for flanges, plugs, and

tubing.

If the static seal is an installation activated seal, the seal and its mating parts must be in contact at a

pressure level greater that the pressure of the fluid to be sealed. This pressure level often is obtained

mechanically.

Other static seal installations are termed pressure-activated. Here the initial sealing pressure is quite low

and is caused by the connecting squeeze of the joint. If that were the only pressure available, the seal

would leak quickly.

However, as system pressure increases, it deforms and reshapes the seal so that sealing pressureincreases to withstand the greater containment requirements. O-rings, V-rings, and other shapes are

typical examples.

QUESTION 8: What are some of the challenges of a dynamic seal?

Reciprocating motion between two members adds a major dimension to the sealing problem. Friction,

and its accompanying wear, joins the list of factors which the design engineer must contend with;

temperature, fluid compatibility, pressure.

The seal used for sealing a reciprocating member must meet static sealing requirements at its contact

area with the stationary member, and also seal effectively at its contact area on the reciprocating

member.

The ideal seal should:

prevent leakage over the pressure ranges encountered

have long life with minimum maintenance

be compatible with fluids at operating temperatures and pressures

have sufficient integrity to avoid fluid contamination


13/23

be easy to install, remove and replace

exclude foreign material

be inexpensive

Curiously, the first two properties are at odds with each other in a dynamic sealing situation. A good

compression forces holding the seal against a reciprocating member accelerate seal wear and shortenservice life. Therefore, every dynamic seal design is a compromise to produce an acceptable balance

between these two desirable properties. The great variety of seal shapes and materials allows the

designer to select the degree of compromise for a particular application while, at the same time,

satisfying the other requirements on the list.

QUESTION 9: Tell me about rotary seals and how they work?

ANSWER: The first rotary shaft seal units were made from leather - the hat shaped until being clamped

between metal pressings to form the outer casing.

Not only were those heavy and expensive to make, but they were true brute force seals relying on

heavy, wide contact between lip and shaft backed up by a powerful coiled garter spring to prevent oilleakage. If it was not for the fact that leather allowed a certain amount of lubricant to find its way to the

interface, the lips would have burned up at much lower speeds than they did. Even so, the peripheral

speeds which could be handled were relatively low and heavy loading resulted in high shaft wear.

The introduction of synthetic rubber in 1938 did not improve matters much since the seal design followed

the principles of leather.

Seal manufacturers began to research the function of oil seals and it was shown that a seal acted like a

bearing - an oil film being generated between lip and shaft. It was demonstrated that so long as a certain

oil film thickness was not exceeded the meniscus which formed at the air side of the interface would not

break and leakage was avoided. Relatively light loads were required to achieve this situation and so

friction was greatly reduced with lower running temperatures and much longer seal life.

For the first time, seals could be designed which would work successfully without trial and error. The

heavy metal cased construction has long since been replaced by a bonded seal using a single metal

pressing with an outer layer of rubber to give a better fluid-tight joint with the machine housing.

It will be appreciated that any damage to the shaft where the seal runs will cause leakage because the

optimum oil film thickness will be exceeded locally. Even a slight scratch can cause leakage so it is of

the utmost importance to provide the right finish on the shaft. To maintain the oil film thickness within its

required limits means that the seal lip must follow any shaft movement. This becomes difficult when the

shaft is subject to eccentric running or vibration at high speeds. An application where such conditions

exist is the rear end of an automotive crankshaft.

Some years ago, fluid seal manufacturers developed what was termed hydrodynamic or positive action

features to help the seal cope with such conditions. These features consisted of raised ribs on the airside of the sealing lip which bedded-in to form tiny projections to catch any oil leaking from the seal and

return it to the oil film under the lip. Such features introduced great reliability to rotary shaft seals for

difficult automotive applications hitherto impossible to achieve.

Although initially the positive action features were unidirectional a fact not of any consequence in many

applications, duo-positive features soon became available making it possible to offer a standard range of

seals of this type, which could be offered for any application without knowledge of the direction of shaft

rotation.


14/23

Question 10: On a hydraulic cylinder, what should I look for and what area should I be concerned about

for its proper performance?

Answer: Good Question. You should pay attention to the following:

EXCESSIVE CLEARANCES - When excess gland clearance exists, either on the inside or outsidediameter of the gland lip or between the piston and cylinder wall, the seal will be subjected to

deformation by extrusion.

Hydraulic pressure will cause the seal to extrude through the excess clearances. Constant pressure

fluctuations will result in loss of sealing material through the clearance causing eventual seal failure.

Prevent this problem by adhering to recommended clearances. NOTE: Care should be taken to properly

centre or align assemblies so that clearance is equal all around.

SCORED RODS, STUFFING BORES OR CYLINDER WALLS - Severe scoring can prevent sealing lips

from conforming to the entire surface to be sealed, resulting in leakage. Rings may never offer a positive

seal if scores are excessively deep, but even if some service is obtained, optimum seal life cannot be

attained. The solution is to refinish the scored rod, stuffing box bore or cylinder wall.

FOREIGN MATERIAL IN HYDRAULIC SYSTEM - Foreign matter in the hydraulic system (dirt, metal

shavings, etc.) can cause many problems with seals, resulting in weepage and premature failure along

with associated equipment damage. Proper filtration and preventative system maintenance solves this

condition.

FAILURE TO MAKE INITIAL SEAL - This is caused by damage to sealing lips during installation. Care

should be taken during insertion, and the use of sharp tools should he avoided. To facilitate installation,

seals may be lubricated with a compatible medium.

EXCESSIVE FLUID TEMPERATURE - Built in interference and/or pressure on the packing is needed to

maintain a positive seal throughout the pressure range. Excessive fluid temperature can cause seal to

lose memory, resulting in fluid leakage, proper seal compound selection and maintenance of nominal

fluid temperature will prevent seal failure.

CHEMICAL ATTACK OF SEAL - Chemical attack to seal is sometimes experienced when using exotic

fluids as hydraulic mediums. Proper compound selection will prevent seal failure.

EXCESSIVE WEARING OF RINGS IN V-PACKING - Premature or excessive wear, particularly on the

dynamic side of V-packing usually indicates that the seal has not been properly seated in the stuffing

box or the piston. This results in the seal set rolling in the box short service life. Proper seating and/or

adjustment will prevent this condition.

WEAR ON ONE SIDE OF SEAL - Conditions exist due to worn bearings or wear rings or rods that cause

misalignment or improper guidance, resulting in excessive wear on one side of the seal. Correction is

attained by rebushing the assembly for proper guidance.

QUESTION 11: Can you make and ship seals the same day?

ANSWER: Yes, using our TURBO SEAL Instant Seal Manufacturing Machine, we can ship seals in a

hurry! An expediting fee is required for same day shipments. For further information on our rapid seal

production clickhere.
http://www.epm.com/sealsfast.htmhttp://www.epm.com/sealsfast.htmhttp://www.epm.com/sealsfast.htm


15/23

QUESTION 12: How do you make seals?

ANSWER: To see how we make seals in our facility in Atlanta, Georgia click here.

QUESTION 13: How large in diameter can you manufacture?

ANSWER: With our MEGA TRUBO SEALS MACHINE we can make inch sizes from 1/64" to 60" and

metrics from 1MM to 1500MM. To see our new MEGA TURBO SEALS MACHINE and for more

information about our large diameter seals click here.

QUESTION 14: How do you I know what delivery services are available for a product?

ANSWER: Look for these color coded images below throughout EPM's site. These will indicate the

service(s) that are available for that particular seal or gasket product.
http://www.epm.com/seal_making.htmhttp://www.epm.com/megaseals.htmhttp://www.epm.com/megaseals.htmhttp://www.epm.com/seal_making.htmhttp://www.epm.com/megaseals.htm


16/23

ABS Acrylonitrile-Butadiene-Styrene (Cycolac )

CHARACTERISTICS: Excellent impact resistance & electrical properties, creep &

moisture resistant.

APPLICATIONS: Electronic housings and panels, decorative coverings.

ACETAL ( Delrin, Celcon, Ensital )

To replace metal in mechanical and structural applications.

CHARACTERISTICS: Excellent machinability, abrasion resistance, low creepage.

Stiffness & tensile strength good under wide range of temperature and humidityconditions.

APPLICATIONS: Mechanical & structural applications, gears, chains, wheels, cams.

DELRIN AF (Acetal Fluorocarbon) Teflon filled delrin adds lubricity.

ENSITAL Static dissipating Acetal.

Delrin CL (Chemically Lubricated) & Glass Reinforced.

ACRYLIC (Acrylite, Plexiglas, Lucite, Staticon,)

For decorative shelving, displays, signage, lighting.

CHARACTERISTICS: Good optical qualities, weather resistant,lightweight.

APPLICATIONS: Decorative shelving & display cases, machine guards, signs.

ACRYLIC MS-2, IIUVA Pre-shrunk, more exacting standards of optical and surface quality.

STATICON Static dissipative acrylic.

KYDEX (Acrylic-PVC Alloy ) High impact, abrasion resistant, & thermoformable.

ALSO AVAILABLE: Abrasion Resistant Cast Acrylic.

FLUOROPLASTICS-Teflon (Teflon, Kel-F, Kynar, Rulon, Tefzel )

Heat, moisture & wear resistant for valve components, gaskets, bearings, washers, electronic

equipment, rings, etc. Good dielectric strength and electrical properties. Low out-gassing undervacuum.

CHARACTERISTICS: High temperature thermoplastic materials, flexible, excellent

dielectric properties.

APPLICATIONS: Valve components, gaskets, bearings, washers, electronic equipment,

rings.


17/23

Film, Tape, Spaghetti Tube, Molded Tube, Shrink Tube & Heat Shrink Rollcovers available.

KEL-F Wide temperature range, excellent chemical & electrical resistance.

KYNAR (PVF2) Outstanding chemical inertness, high dielectric strength, self-extinguishing.

RULON Specially compounded forms of TFE fluorocarbons & other inert ingredients.

NOMEX

Heat resistant nylon paper for insulation, heat formed parts.

CHARACTERISTICS: High temperature nylon paper. Offers electrical, thermal, &

mechanical properties unique to a flame resistant insulation material.

APPLICATIONS: Insulation, heat formed parts, cable wrap, printed circuit backing.

Sheet available.

NORYL (Modified Polyphenylene Oxide)

For electrical & electronic equipment, door panels, etc.

CHARACTERISTICS: Self extinguishing, high impact resistance, lightweight.

APPLICATIONS: Electrical and electronic equipment, door panels.

NYLON (Nyoil, Vekton, Nycast, Ensilon, Hydlar) CHARACTERISTICS: Nylon 6 & Nylon 6/6 have higher tensile & compressive

strengths but lower percent elongation. Nylon 6/12 is often used in electrical applications

due to low water absorption. Superior impact resistance, good chemical and abrasionresistance.

APPLICATIONS: Gears, wear strips, rollers, pulleys, thrust washers, valves, bushings.

GLASS-FILLED Glass strands improve nylons tensile & compressive strength & stiffness.

HYDLAR Nylon reinforced with Kevlar , good wear resistance, high impact strength.

NYOIL Internally lubricated cast nylon, long wearing, self-lubricating with low friction.

NYCAST (Nylon MD) Molybdenum disulfide lowers the coefficient of friction of nylon.

PHENOLIC LAMINATES (Micarta, Bakelite )

For insulating washers, bushings, spacers, terminal boards, bearings, sockets.

CHARACTERISTICS: Thermosetting resin & reinforcing matrix. Resins available are

phenolic, epoxy, melamines, silicone, polyester, & teflon. Reinforcing materials are glass,


18/23

cotton, & paper. These reinforcing materials provide omni-directional strength. Good

dielectric strength, dimensional stability, machinability, & chemical resistance.

APPLICATIONS: Insulating washers, bushings, spacers, terminal boards, bearings,

sockets.

GLASS BASED: FR-4 Glass Epoxy. G-11, G-5, G-9 Melamine, G-7 Silicone.COTTON BASED: LE Linen Phenolic. / CE Canvas Phenolic.

PAPER BASED: Paper Phenolic. Grades- XXXPC, XPC.

POLYCARBONATE (Lexan, Hyzod, Cyrolon, Staticon)

Highest impact rating of all transparent thermoplastics for burglar-resistant glazing, impact

shields, electronic housings, machine guards. High dielectric strength, is 94V0 in 1/8" thickness.

CHARACTERISTICS: High impact thermoplastic, machinable, thermoformable, good

light transmission and dimensional stability.

APPLICATIONS: Burglar resistant glazing, impact shields, electronic housings, aircraft

panels, machine guards.

ALSO AVAILABLE: Glass-Filled, Mar Resistant, Flame Retardant, Static Dissapative.

POLYESTER (Mylar, Valox, PBT, Hydex 4101)

For gears, microfilm, graphic arts, decorative laminations, electrical insulators.

CHARACTERISTICS: Outstanding thermal resistance, good lubricity & smoothness.

APPLICATIONS: Gears, graphic arts, decorative laminations, electrical insulators.

Sheet, Rod & Film available.

ALSO AVAILABLE: GPO-1, 2, & 3, PET, Fiberglass, Mylar (Type A, S & D), Valox

POLYETHERETHERKETONE PEEK (VicTrex)

CHARACTERISTICS: Very high continuous use temperature, chemical resistance, wear

resistance, excellent mechanical properties.

APPLICATIONS: Electronics, aerospace, medical and analytical equipment.

Sheet, rod and custom molded shapes.

ALSO AVAILABLE ON QUOTATION: Glass fiber, graphite, carbon-fibre and PTFE Filled.


19/23

POLYETHERIMIDE (Ultem)

CHARACTERISTICS: High mechanical strength and rigidity, high continuous use

temperature, good chemical resistance.

APPLICATIONS: Electronics, aerospace, medical and analytical equipment.

Sheet, rod and custom extrusions.

ALSO AVAILABLE ON QUOTATION: Glass reinforced, carbon fiber and PTFE Filled.

POLYIMIDE (Kapton, Vespel )

Kapton- For insulation tape, flexible printed circuit base and flat cable.

Vespel- For retention of physical properties over a wide temperature range.

CHARACTERISTICS: Strong, high resistant, excellent mechanical & electricalproperties.

APPLICATIONS: Insulation tape, base for flexible printed circuits & flat cable.

FILM AVAILABLE: (Kapton Type H, V,and F).

SHEET: up to 2" Thick

ROD: up to 3" Diameter

POLYOLEFINS Polyethylenes & Polypropylene (UHMW ) & Polyslick 502

For machine wear strips, chutes, conveyors.

POLYETHYLENE: UHMW (Ultra High Molecular Weight), Low & High Density

Polyethylene.

CHARACTERISTICS: Outstanding Dielectric Properties, excellent chemical resistance.

APPLICATIONS: Machine Wear strips, chutes, conveyors, insulators.

CONDUCTIVE UHMW:

CHARACTERISTICS: Conducts Electricity

APPLICATIONS: Electronic Conveyor Wear Strips

POLYPROPYLENE:


20/23

CHARACTERISTICS: Good Balance of properties, excellent electrical properties.

APPLICATIONS: Chemical tanks, orthopedic applications.

POLYSTYRENE

For packaging, radio & TV cabinets, lighting, and automotive.

CHARACTERISTICS: Outstanding electrical properties, excellent machinability and

dimensional stability, rigid & lightweight.

APPLICATIONS: Packaging, lighting, automotive.

Sheet, Rod, and Tube available.

HI-IMPACT POLYSTYRENE A co-polymer of styrene and unsaturated rubbers such aspolybutadiene.

ALSO AVAILABLE: Rexolite (Cross Linked Polystyrene).

POLYURETHANE (Versathane, Isoplast)

For strippers, gaskets, seals, bumpers, gears, rings, roll covers.

CHARACTERISTICS: Tough and durable, broad hardness range, remarkable abrasion

resistance, high flex-life, cut resistant, load-bearing capacity, & outstanding resistance to

weather.

APPLICATIONS: Strippers, gaskets, seals, bumpers, gears, rings, roll covers.

VERSATHANE & URETHANE FABRICATED PARTS. Tough, economical, lightweightmaterial. Used as metal casting replacements, corrosion resistant parts, large industrial parts,

insulators, handles, clamps & machine stock. Cast to your specifications.

POLYVINYL CHLORIDE (PVC)

For tanks, valves, hoods, electrical tape, industrial pipe, insulation sleeving.

CHARACTERISTICS: Excellent chemical resistance, good machining properties, self

extinguishing, solvent cementable, & Thermoformable.

APPLICATIONS: Tanks, valves, hoods, electrical tape, industrial pipe, insulation

sleeving.


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LAMINATESNorplex laminates below are just a selected sample, click on the link for full data sheets and other types.

Industrial Laminates/Norplex - Glass and Carbon Fiber

Fabric Base LaminatesWith the exception of carbon fiber, woven glass fabrics provide the strongest laminates that theindustry produces. The glass fabric is made from "E" glass, which is a special composition using a

borosilicate glass designed for the laminating industry. The glass fabric product with the largest

usage is NEMA FR-4. FR-4 typically uses an epoxy resin system with a brominated epoxy resinbackbone. Epoxy glass laminates, especially FR-4, offer the best combination of properties at the

most reasonable cost. There are several other types of epoxy glass laminates available, which

tailor the requirements to the application.

Melamine resin and glass fabric composite is probably the second most popular product. The

melamine resin system imparts flame and arc resistance to the final product. Phenolic resins arealso used, to provide heat resistance. The final resin system used on glass fabric are the

polyimides. Polyimide resin systems impart superior properties to a composite, combining the

temperature resistance of phenolics and the electrical properties of epoxies. They maintain their

physical and electrical properties at temperatures over 500F.

Carbon fiber fabric is combined with high temperature epoxies and phenolic resin systems to

product composites which have the highest flexural strength and modulus and tensile strength ofany composite. They are also very light weight, having a specific gravity of approximately 1.45

versus 1.90 for high strength epoxy glass laminates. However, carbon fiber fabric laminates cannot

be used in electrical applications because of the conductivity of the carbon fiber filaments.

Grade: G-10

NEMA Grade G-10

U.L. Listed: Y

Description:

Glass fabric with epoxy resin system. Combines excellent electrical characteristics with superior

physical properties. Electrical properties maintained in high humidity conditions. Not flame

resistant. Material meets NEMA G-10 and can be produced to the NIST G10CR processspecification for materials used in cryogenic applications.

Grade: ED130

NEMA Grade: FR-4U.L. Listed: Y

Description:

Woven glass fabric with a brominated epoxy resin system. Used primarily in the printed circuit

board industry. Flame retardant, meets U.L. flammability classification 94V-0.

Thickness Tested: 0.0620", 0.1250" and 0.500"

Grade: NP510HF
http://www.norplex.com/tier3pgs/glaframes/glaframe.htmhttp://www.norplex.com/tier3pgs/glaframes/glaframe.htm


22/23

NEMA Grade: FR-4

U.L. Listed: Pending

Description:

High flexural, impact and tensile strength glass fabric epoxy laminate, especially in the machine

direction. Engineered to provide better physical properties, flexural, compressive, and impact

strength, than NEMA FR-4. More dimensionally stable than standard NP510A. Application is for"bed-of-nails" equipment for printed circuit board testing. MIL-I-24768/27, type GEE-F.

Thickness Tested: 0.062", 0.125" and 0.500"

Grade: NP841

NEMA Grade:

U.L. Listed: NDescription:

Woven glass fabric with phenolic resin. Contains Kocite for controlled conductivity. Acts as static

electricity drain to protect electrical and electronic equipment. Thickness Tested: 0.062", 0.125"

and 0.500"

Grade: NP509FW

NEMA Grade: G-9

U.L. Listed: YDescription:

Fine weave glass fabric with melamine resin binder. Very hard, flame resistant, machining grade

with excellent electrical properties in high humidity conditions. Fine weave fabric allows betterpunching with finer edges. High physical strength. and excellent arc resistance. Meets U.L.

flammability classification 94V-0. Thickness Tested: 0.062", 0.125" and 0.500"

Polyguide LaminatesPolyguide clad laminates and dielectrics are precision fabricated from the highest quality, highdensity polyolefin available. Irradiation cross-linking of the polyolefin permanently imparts

improved electrical homogeneity and mechanical toughness, while significanlty enhancing the

temperature and chemical resistance of the material. These laminates are impervious to solventsand solutions used in microwave circuit processing and fabrication.

The superior electrical properties of Polyguide remain constant throughout a broad range ofoperating condidtions and frequencies, up to and beyond 18GHz.

No adhesives or intermediates are used in the lamination of Polyguide

NorCLAD Laminates

Polyflon's NorCLAD laminates, made from the thermoplastic PPO (Polyphenylene Oxide), havean ideal dielectric constant of 2.55, very uniform and reproducible electrical properties, and are

stable over temperature.

When first introduced in the 60's, PPO was touted as the ultimate dielectric for RF/Microwavelaminates. However, as a circuit board material, its usage was restricted by the solvent based
http://www.polyflon.com/polyguid.htmlhttp://www.polyflon.com/norclad.htmlhttp://www.polyflon.com/polyguid.htmlhttp://www.polyflon.com/norclad.html


23/23

processing chemicals popular at that time. Polyflon's NorCLAD laminates, being impervious to

today's aqueous processing methods, is ideal for RF and microwave applications

No adhesives or intermediates are used in the lamination of NorCLAD

Documents

Viton Properties