Zetpol Technical Manual

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Zetpol Technical Manual

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Table of Contents

Table of Contents ............................................................................................................................ 1

What are Zetpol Polymers? ............................................................................................................. 5

Zetpol Product Selection ............................................................................................................. 6

Standard High-ACN Grades .................................................................................................. 12

Standard Medium-ACN Grades ............................................................................................ 13

Low-Temperature Grades ...................................................................................................... 14

Easy Processing Grades ......................................................................................................... 14

Zeoforte (ZSC) Grades .......................................................................................................... 15

Where Zetpol is used today ........................................................................................................... 18

Automotive ................................................................................................................................ 18

Gaskets and Seals .................................................................................................................. 18

Diaphragms ............................................................................................................................ 20

Belts ....................................................................................................................................... 21

Coolant Applications ............................................................................................................. 23

Oilfield ...................................................................................................................................... 25

Blow Out Preventers (BOP) .................................................................................................. 30

Packers ................................................................................................................................... 31

Stators and pump motors ....................................................................................................... 32

Drill bit seals .......................................................................................................................... 34

Rolls .......................................................................................................................................... 36

Processing Zetpol Compounds ..................................................................................................... 42

Zetpol Compounding................................................................................................................. 43

Polymers ................................................................................................................................ 44

Carbon Black Fillers .............................................................................................................. 44

Non-black Fillers ................................................................................................................... 50

Plasticizers ............................................................................................................................. 55

Metal Oxides.......................................................................................................................... 59

Antioxidants........................................................................................................................... 62

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Process Aids .......................................................................................................................... 67

Co-agent/Accelerators ........................................................................................................... 70

Curatives ................................................................................................................................ 74

Mixing ....................................................................................................................................... 82

Molding Zetpol Compounds ..................................................................................................... 82

Compression/ Transfer Molding ............................................................................................ 83

Extrusion ................................................................................................................................ 84

Injection Molding .................................................................................................................. 84

Contact Information ...................................................................................................................... 87

Figures and Tables ........................................................................................................................ 88

Index ............................................................................................................................................. 90

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Product Selection

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What are Zetpol Polymers?

For many years nitrile polymers performance in both the automotive and energy fields has been

excellent. However, modern applications limit their function due to resistance to heat, ozone,

amines, sour crude, sour gasoline, oxidized oil and oil additives. By saturating the butadiene

portion of the backbone of the nitrile polymer during selective hydrogenation with a new

polymer, hydrogenated nitriles were developed to overcome these deficiencies while maintaining

the basic oil, fuel, solvent resistance (Figure 1). Nippon Zeon Company Ltd. developed and

commercialized Zetpol in 1984, the first hydrogenated nitrile rubber (HNBR) designed

specifically to address the demands of these applications.

Figure 1- Overview of HNBR Process

Zetpol polymers find use in a wide range of applications encompassing the automotive, energy

sector and industrial roll markets. Due to the hydrogenation of the butadiene, Zetpol compounds

offer similar fluid resistance as nitrile compounds but offer improvements in heat and chemical

resistance not permissible in nitrile compounds. Zetpol compounds are serviceable over a wide

range of temperatures from -40C to 150C providing excellent long-term temperature

Packaging

Drying

CoagulationSeparationHydrogenation

Reaction

Hydrogen

Dissolution

NBR

HNBR Production Process

Dissolution

SolventComputer

Control

Center

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resistance. Zetpol elastomers are classified by the ASTM D-2000 or the SAE J-200 as DH and

DK polymers. Zetpol applications often require high tensile and modulus values. Along with

these excellent properties, Zetpol compounds have superb resistance to steam and ultraviolet

radiation.

Zetpol products demonstrate excellent resistance against many modern automotive fluids such

as engine oils, ATF, power steering fluid and coolants, including extended-life coolants,

allowing for unique sealing applications to be overcome. This uniqueness can be extended to

include many fuels used today all over the world including excellent resistance to many modern

fuels such as biodiesel. Zetpol compounds meet the demanding requirements for service in the

energy industry by providing a tough polymer, resistant to the fluids and chemicals found in

todays oil wells. The hydrogenation process improves resistance to hydrogen sulfide and amines

frequently seen in the energy sector. This same process improves the resistance to many acids

and alkalis seen in both the energy and roll applications. While not unique to roll applications,

Zetpol compounds have shown improvements for dynamic applications such as hysteresis and

vibration transmission.

Zetpol Product Selection

Zetpol polymers are high-temperature, chemical and oil resistance elastomers. These polymers

are compounded to meet demanding market needs over a wide operational range for many

applications needing excellent properties. When choosing a Zetpol polymer for a specific

application there are three basic criteria to keep in mind for excellent performance. These criteria

are acrylonitrile content, hydrogenation level and polymer Mooney viscosity. The acrylonitrile

content affects the fluid resistance as well as low-temperature performance. Heat, chemical and

ozone resistance are influence by the ethylene content or level of hydrogenation (Figure 2). Last,

understanding compound processability is an important factor for selecting the proper polymer

viscosity that will affect both flow and final properties.

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Figure 2-General HNBR Polymer Composition

Zetpol is a highly saturated nitrile polymer consisting of acrylonitrile groups, ethylene chains and

butadiene carbon-to-carbon double bonds. This structure after hydrogenation consisting of

acrylonitrile groups provides oil, fuel and solvent resistance plus good abrasion resistance and

high physical properties. The effect of the acrylonitrile on volume swell in standard test fluids

such as IRM 903 can be seen in Figure 3. The saturated ethylene chains provide not only the

rubber elasticity, chemical stability and heat resistance as well as ozone protection. As the

hydrogenation increases with the base nitrile polymer, elongation property changes with

increasing saturation improves in direct relation to the saturation. Figure 4 below illustrates the

saturation level for Zetpol polymers when aged at 168 hours at 150C. The presence of a small

amount of the unsaturated butadiene group, typically between 0.2% and 15%, allows

vulcanization with sulfur or peroxide cure systems.

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Figure 3- Effects of ACN Level on Fluid Resistance

Figure 4- Effects of Saturation Levels on Heat Ageing

The acrylonitrile groups in Zetpol polymers provide resistance for many fluids encountered in

todays applications. Cold-temperature flexibility is important in many applications. The nitrile

group is a semi-crystalline structure with a glass transition above 100C. This transition

temperature will hinder polymer mobility in low-temperature applications. To address many low-

temperature applications Zeon developed Zetpol polymers with excellent low-temperature

properties through novel polymer structures to maintain typical Zetpol properties, while

-10

-5

0

5

10

15

20

25

30

35

15 20 25 30 35 40 45 50

Volu

me

Sw

ell,

%

Polymer ACN Level

IRM 901 IRM 903

-100

-80

-60

-40

-20

0

60 70 80 90 100

Elo

ngat

ion C

han

ge

(%)

Polymer Saturation (%)

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improving low-temperature performance. Evaluation of different acrylonitrile levels in Zetpol

polymers by both low-temperature retraction and Gehman tests illustrate the relationship

between low-temperature performance and acrylonitrile levels (Figure 5).

Figure 5- Low-Temperature Performance by ACN Level for Zetpol Polymers

A similar evaluation studying the relationship between acrylonitrile level and polymer saturation

was completed. In this evaluation the Zetpol polymers used were all 36% ACN but varied by the

degree of hydrogenation of butadiene groups. The degree of saturation remaining in Zetpol

polymers should not influence low-temperature performance as much as the level of acrylonitrile

(Figure 6).

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

17% AN 25% AN 36% AN 44% AN 50% AN Te

mp

era

ture

, C

TR10 T100

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Figure 6- Low-Temperature Performance by Saturation Level for Zetpol Polymers

Producing Zetpol polymers with different Mooney viscosities is not new. Zeon has produced

Zetpol polymers with varied viscosities for many years. Examples would be Zetpol 2010H,

2010, 2010L and 2010EP (Table 1). The Mooney viscosity, ML 1+4 @100C, for Zetpol 2010H

is above 120 while the Zetpol 2010EP is as low as 25. This range of viscosity addresses different

applications and molding conditions customers face daily. These polymers may be blended to

achieve optimal processing while maintaining the desired compound properties typical for

Zetpol.

Zetpol

2010EP

Zetpol

2010L

Zetpol

2010

Zetpol

2010H

Mooney

Viscosity,

100C,

ML 1+4

25 35 50 65 78 92 >120

Table 1- Examples of Mooney Viscosities

-40

-35

-30

-25

-20

-15

-10

-5

0

99% HYD 96% HYD 91% HYD 85% HYD

Tem

pe

ratu

re,

C

TR10 T100

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There are several polymer types based on the different levels of these three criteria in the product

line including a specialty polymer. The Zetpol product line is categorized based on acrylonitrile

level. Within each level the products are furthered classified based on the hydrogenation level

and Mooney viscosity. There is a basic nomenclature for the Zetpol product line illustrated

below:

One product, Zeoforte ZSC has high physical properties coupled with excellent abrasion and

toughness. ZSC polymers have low hysteresis properties making this polymer a fine choice for

applications where heat buildup and abrasion resistance are required. The basic nomenclature

for the Zeoforte ZSC product line is illustrated below:

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Standard High-ACN Grades Applications requiring excellent resistance to fuels should consider

using a Zetpol grade with high acrylonitrile content (Figure 7). These polymers provide the

resistance to both standard and bio fuels serving both current and future engine designs. Besides

resistance to fuels these polymers can also serve well in applications needing excellent

permeation resistance. These polymers can also be compounded to meet the demanding

requirements for many oil field applications such as stators and pump pistons.

Polymer

ML1+4

@

100C

%

ACN

%

HYD Polymer Characteristics

Zetpol 0020 58-72 50 91 Excellent performance in fuels,

flex fuels and MTBE

Zetpol 1000L 58-72 44 98 Low-Mooney polymer for fuel

and oilfield applications

Zetpol 1010 78-92 44 96 For fuel-resistance hoses,

diaphragms, and seals

Zetpol 1020 71-85 44 91 Same as Zetpol 1010 but lower

saturation level for sulfur curing

Zetpol 1020L 47-67 44 91 Lower Mooney version of Zetpol

1020

Figure 7- High-ACN Polymer Grades

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Standard Medium-ACN Grades These medium-ACN grades are the workhorse of the Zetpol

product line (Figure 8). The applications served by these polymers include automotive, oilfield

and rolls. These Zetpol polymers with 36% acrylonitrile offer an excellent balance of properties

and are used in many applications from small seals and O-rings to large blowout preventers and

packers used in oil field service. The service temperature for the medium-ACN grades can be

compounded to meet -25C to 150C. These medium-ACN grades offer a broad range of

hydrogenation levels making them well suited for a number of applications. The range of

hydrogenation levels allows all of them to be peroxide cured and several polymer choices can be

cured with traditional sulfur systems.

Polymer

ML1+4

@

100C

%

ACN

%


Zetpol 2000 78-92 36 >99.5 150C high-temperature service and

excellent oil resistance.

Zetpol 2000L 58-72 36 >99.5 Improved low-temperature and


Zetpol 2010H >120 36 96 Improved low-temperature and


Zetpol 2010 78-92 36 96 150C high-temperature service and


Zetpol 2010L 50-65 36 96 Improved low-temperature and


Zetpol 2011L 53-63 36 94 150C high-temperature service and


Zetpol 2020 71-85 36 91 Improved low-temperature and


Zetpol 2020L 50-65 36 91 150C high-temperature service and


Zetpol 2030H >110 36 85 Improved low-temperature and


Zetpol 2030L 50-65 36 85 Good balance of heat and oil

resistance.

Figure 8- Medium-ACN Polymer Grades

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Low-Temperature Grades The ACN content provides excellent resistance to fluids but affects

low-temperature performance (Figure 9). Performance at low-temperature is critical in many

applications for both automotive and oil field parts. In applications requiring low-temperature

flexibility below -30C these polymers are recommended. These grades can easily perform at

temperatures of -40C while providing physical properties similar to medium-ACN grades.

Polymer

ML1+4

@

100C

%

ACN

%


3310 60 -

100 25 95

Improved low-temperature

performance (TR10 of -33C) with

balanced properties

4300 55 - 95 17 >99.5 Fully saturated version of Zetpol

4310

4310 52 - 72 17 95

Improved low-temperature

performance (TR10 of -36C) with

balanced properties

Figure 9- Low-Temperature Grade Polymers

Easy Processing Grades With increasing emphasis on cost savings in todays global market,

molded goods manufacturers are looking for ways to reduce their overall processing cost. Often

this can be accomplished by using a lower-viscosity polymer. A new generation of Zetpol

polymers is now offered which addresses these issues and overcomes processing and

compounding problems (Figure 10). These new polymers exhibit improved processability while

maintaining high mechanical strength and compression set resistance. They are appropriate for

injection molding, transfer molding, compression molding and extrusion.

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Polymer

ML1+4

@

100C

%

ACN

%


0020EP 33 - 47 50 91 Excellent processing version of Zetpol

0020


1010


1020

2000EP 23 - 37 36 >99.5 Excellent processing version of Zetpol

2000


2010


2020


2030


3310

4300EP 23 - 37 17 >99.5 Excellent processing version of Zetpol

4300


4320

Figure 10- Easy Processing Polymer Grades

Zeoforte (ZSC) Grades Zeoforte ZSC, or ZSC, is based on a modification of standard Zetpol

polymer grades. This provides unique polymer properties which offer improvements in tensile

strength, abrasion resistance and dynamic properties. Ultrahigh-tensile strengths can be achieved

with these polymers providing solutions for demanding applications such as belts and oil field

(Figure 11). The improvements in abrasion resistance coupled with the improvements in

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dynamic performance make these polymers an excellent choice for demanding roll applications.

ZSC polymers can be blended with standard Zetpol polymer grades to provide balanced

compound properties.

ZSC

Polymer

ML1+4

@

100C

%

ACN

%


2295CX 75- 110 36 91

Zetpol 2020 modified with zinc

methacrylate for outstanding tensile, tear,

abrasion and high elongation at high

hardness (Shore A>95)

2295L 72 - 89 36 91 Low-Mooney version of ZSC 2295CX for

improved processing

2395 60 - 80 36 85

Zetpol 2030L modified with zinc

methacrylate for outstanding tensile, tear,

abrasion and high elongation at high

hardness (Shore A>95). Excellent strength

and durability with low hysteresis for roll

covers and other high-load applications

Figure 11- Zeoforte ZSC Grades

The use of an external mold release is vital to successful molding compounds containing

Zeoforte ZSC. Compounds with loading greater than 50 parts of Zeoforte ZSC will require the

use of an external mold release. Without the use of a mold release, Zeoforte ZSC compounds

will adhere to the metal mold causing downtime and possible mold damage. Zeon Chemicals has

tested several external mold releases for use with Zeoforte ZSC compounds. Diamond Kote

W59 from Franklynn Industries provides good release characteristics with minimal degradation

in physical properties of the compound or surface contamination.

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Applications

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Where Zetpol is used today

The key assets for Zetpol polymers are their resistance to a wide range of fluids, the intrinsic

toughness giving Zetpol compounds excellent mechanical properties. It is not surprising that

Zetpol compounds are in many demanding applications around the globe, which require

excellent fluid and heat resistance coupled with the inherent polymer toughness. These

applications span the range in size from the smallest O-ring in automotive markets to large

blowout preventers in drilling operations for the energy sector.

Automotive

Automotive applications use Zetpol compounds in a range of functions, which require the unique

properties of HNBR polymers. With the continued trend to ever-decreasing space in the engine

bay, temperatures continue to rise, placing ever more demands on the components operating in

this environment. One consequence of this is the need for elastomers capable of ever-greater

long-term high temperature resistance. Todays elastomer must withstand harsh environments in

the engine compartment. Higher operating temperatures have resulted in the development of

more aggressive automotive fluids and lubricants, further necessitating the use of specialty

elastomers that have both greater heat and fluid resistance. The automotive industry seeks a

tough elastomer with improved resistance to chemical, fuel and heat. Zetpol polymers offer a

unique combination of resistance to coolants, fuels and oils used in todays vehicles while

providing excellent compression set resistance.

Gaskets and Seals The automotive industry faces many challenges in todays market. Customers

are demanding improvements in reliability, longer warranties and increased performance.

Customers are also seeking more environmentally friendly designs. However, these newer

designs limit the space in the engine compartment resulting in increases in temperatures. To the

gasket and sealing supplier, these design improvements require increases in the performance of

the sealing materials. Zetpol polymers are unique in their performance in the automotive

applications combining both superior heat and oil resistance to meet the challenges by providing

a polymer with outstanding chemical and heat resistance coupled with wear resistance for the

modern automotive application.

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Zetpol 2000L is a fully saturated polymer providing outstanding long-term heat resistance and

excellent compression set properties for gasket and sealing applications. With the high

hydrogenation level in Zetpol 2000L the ethylene gives this polymer outstanding long-term heat

resistance and compression set. The compound demonstrates both excellent compression set

resistance both in air and SF 105G at 150C (Figure 12). The compressive stress relaxation for

Zetpol 2000L compares well with the compression set response. Zetpol 2000L maintains more

than 50% of its original forces in both air and SF 105G after 1008 hours (Figure 13).

Figure 12- Long-Term Compression Set

0

10

20

30

40

50

0 168 336 504 672 840 1008

Co

mp

ress

ion

Se

t, %

Time, hours

Air SF 105G

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Figure 13- Continuous Compressive Stress Relaxation Testing

Diaphragms With the exceptional strength and heat resistance provided by the ethylene content,

Zetpol polymers are an excellent choice for diaphragm applications. With an extensive range of

hydrogenation levels the desired flex characteristics are easily obtained. Zetpol polymers can

also meet the demands for fluid resistance by offering enhanced performance in many fluids that

are encountered in these applications. The acrylonitrile content in Zetpol polymers will meet this

demand.

Permeation resistance is critical for many applications today and Zetpol polymers meet these

demands in many applications. The acrylonitrile provides the permeation resistance needed for

improvements to resist infiltration of fluids and gases. In a study with Zetpols 1020, 2010H and

3310, the permeation resistance improved with increased acrylonitrile content in the polymer.

Zetpol 1020 with its high ACN content provides excellent resistance to refrigerants in many air

conditioning applications (Figure 14).

0

0.25

0.5

0.75

1

0 168 336 504 672 840 1008

Re

tain

ed

Fo

rce

, F/F

o

Time, hours

Air SF 105G

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Figure 14- Refrigerant R-134a, mg*mm/cm^3 per day

Belts The use of elastomers in belts for the automotive industry has accelerated. The increasing

demands placed on belts, along with increased customer expectations, have pushed the materials

industry to develop elastomers that meet these demands by providing higher load-carrying

capacities and longer service lives while performing at service temperatures (150C).

Zetpol polymers established a new benchmark for the performance requirements of synchronous

and serpentine belts opening the door to wide-scale adoption of elastomer belts in both

automobiles and industrial equipment. Zetpol performance has been further extended by the

introduction of Zeoforte ZSC. ZSC is a unique, high-performance HNBR-based elastomer

which has superior abrasion resistance, physical properties, and load-bearing capabilities.

Together, Zetpol and Zeoforte ZSC continue to redefine and revolutionize synchronous and

serpentine belting markets.

Compounding studies show Zetpol 2020 and blends of Zetpol 2020 with Zeoforte ZSC 2295CX

to have excellent performance. The wear resistance for these compounds demonstrates this

performance. The abrasion resistance was measured by the Taber abrader using an H22 wheel

and a one-kilogram weight. The Zetpol 2020 blended with the ZSC 2295CX shows superior

abrasion resistance (Figure 15).

0

20

40

60

80

100

120

140

Z- 1020 Z-2010H Z-3310

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Figure 15- Taber Abrasion Resistance for Belt Compounds

Zetpol polymers have excellent tensile properties providing the needed performance in many

demanding applications such as belts. As illustrated, the tensile properties for the Zetpol 2020

and the blend of Zetpol 2020 and ZSC 2295CX provide the needed strength for the increased

loads in belt applications (Figure 16). The dynamic property measurement illustrates minimal

hysteresis or heat buildup for these compounds based on the low tan value. These dynamic

properties evaluations were conducted in tension at 50Hz at both room temperature and at 135C

(Figure 17).

Figure 16- Tensile Strength for Zetpol Belt Compounds

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Zetpol 2020 Zetpol/ ZSC Blend

We

igh

t lo

ss, g

ram

s

0

5

10

15

20

25

30

35

40


Ten

sile

, Mp

a

23C

135C

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Figure 17- Compound Dynamic Properties

Coolant Applications Due to the chemical and fluid resistance inherent to Zetpol polymers, they

make an excellent choice for sealing coolant applications. The Zetpol compounds used to

determine the effects of an organic acid technology (OAT) coolant after long-term exposure

were Zetpols 2000 and 2010. This evaluation measured the physical property response after

1008, 2016 and 3024 hours at 135C and 150C. There is no clear difference in the retained

properties for Zetpols 2000 and 2010 at 135C (Figures 18). At 150C, the Zetpol 2010

compound retains slightly more tensile after 3024 hours than the Zetpol 2000, while the

remaining physical properties are similar to the Zetpol 2000 compound (Figure 19).

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16


tan

de

lta

23C

135C

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Figure 18- Long-Term Aging in OAT Coolant at 135C

Figure 19- Long-Term Aging in OAT Coolant at 150C

There is one important compounding note for water and coolant applications with Zetpol

polymers. When developing a recipe for direct contact with water know that zinc will increase

the swell in these fluids. Some of the common compound ingredients used will need to be

replaced to ensure long-term stability in these environments.

-15

-10

-5

0

5

10

15

20

1008 2016 3024 1008 2016 3024

Zetpol 2000 Zetpol 2010

Pro

pe

rty

Ch

ange

Hardness Ch. Tensile Ch. Elongation Ch Volume Swell

-25

-20

-15

-10

-5

0

5

10

15

20

1008 2016 3024 1008 2016 3024


Pro

pe

rty

Ch

ange

Hardness Ch. Tensile Ch. Elongation Ch Volume Swell

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Oilfield

Zetpol compounds meet the extreme demands of oilfield applications which require excellent

properties to meet the harsh conditions seen in this industry. While Zetpol polymers can

withstand the harsh abuse encountered in drilling operations, these compounds are also able to

stand up to the high temperatures and pressures encountered in the well upon completion.

Coupled with the excellent resistance to the various fluids such as crude oil, gases, acids and

alkalis, Zetpol compounds can meet the demands required for application in these harsh

environments.

The oil industry is pushing the edge of existing technology, requiring innovative solutions to a

wide range of problems. The diverse combination of conditions present in the down-hole

environment is a constant challenge for materials and to design engineers. With oil wells getting

deeper and the conditions becoming harsher, traditionally used materials can no longer provide

the performance required. In these deeper wells, elastomers encounter chemicals such as amine

corrosion inhibitors, hydrogen sulfide (H2S), and temperatures can reach and exceed 175C.

Zetpol polymers are ideally suited for these aggressive down-hole environments.

Zetpol polymers offer an improved balance of thermal and chemical stability over nitrile

polymers. HNBR polymers formulations offer a balance over a broad temperature range, -40 to

175C. Additionally, Zetpol polymers have excellent resistance to amine corrosion inhibitors,

hydrogen sulfide, steam, and other common oil field materials. It is this balance of properties

which make Zetpol the ideal elastomer for oil field and down-hole applications.

Amine corrosion inhibitors, coupled with the higher temperatures encountered in todays wells,

have created problems for traditional oil-resistant elastomers. Zetpol polymers are minimally

affected by amine corrosion inhibitors and high temperatures. To compare performance in an

amine-rich environment, elastomers were tested at 150C for 168 hours in IRM 902 oil and IRM

902 oil containing 1% NACE Amine B. Each Zetpol polymer had reasonable swell properties

(Figure 20). Comparisons of elongation changes after fluid aging indicate Zetpol 2010 offers

better property retention than Zetpol 1020 (Figure 21).

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Figure 20- Volume Swell Data in IRM 902 & Amine

Figure 21- Volume Swell Data in IRM 902 & Amine

Sour wells, those containing hydrogen sulfide (H2S), create unique challenges for elastomer

manufacturers. Significant degradation will occur in some polymers when exposed to hydrogen

sulfide-rich gas and liquid leading to premature and expensive failure in key down-hole

components. Zetpol polymers performance in these environments offers advantages in both gas

and liquid phase H2S.

0

2

4

6

8

10

12

14


Vo

lum

e S

we

ll, %

IRM 902 Oil 1% NACE Amine B in IRM 902 Oil

0

5

10

15

20

25

30

35


Elo

nga

tio

n P

rop

ert

y C

han

ge, %

IRM 902 Oil 1% NACE Amine B in IRM 902 Oil

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Evaluations of Zetpol 2010 and 1020 in 5% by volume hydrogen sulfide in both gas and liquid

phase studied the influence on physical properties (Figures 22 & 23). It is clear that Zetpol 2010

and Zetpol 1020 show outstanding retention of tensile strength, even after 168 hours exposure.

Zetpol 2010, in particular, shows excellent results as evidenced by an elongation loss of only 9%

and a hardness drop of only 5 points. The trends from the gas phase aging are further amplified

in the liquid phase testing. The drop in tensile strength is 24% for Zetpol 2010 and 30% for

Zetpol 1020 after 168 hours exposure. The elongation change and other properties for the Zetpol

2010 compound are similar to those in the gas phase. Zetpol 2010 performed well in the sour

environments.

Figure 22- H2S Gas Phase Compound Properties

-60

-40

-20

0

20

40

60

24 hrs 72 hrs 168 hrs 24 hrs 72 hrs 168 hrs

Zetpol 2010 Zetpol 1020 Pro

pe

rty

Ch

ange

s

Hardness Ch, pts Tensile Ch, % Elongation Ch, % 50% Mod Ch, %

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Figure 23- H2S Liquid Phase Compound Properties

Elastomeric components are often exposed to steam in down-hole environments during well

work-over and recovery operations. To be effective, an elastomer should not swell or soften

when exposed to steam. Zetpol polymers are not severely degraded when exposed to steam for

168 hours at 150C. A comparison of volume swell shows no significant swell in steam and

there is no hardness drop for the Zetpol 2010 compound. Additionally, Zetpol 2010 tensile and

elongation properties are largely unaffected by exposure to steam (Figure 24). By contrast, the

Zetpol 1020 compound exhibited a significant drop in elongation properties at these

temperatures.

Figure 24- Steam Resistance for Zetpol Compounds

-60

-40

-20

0

20

24 hrs 72 hrs 168 hrs 24 hrs 72 hrs 168 hrs


Pro

per

ty C

han

ges

Hardness Ch, pts Tensile Ch, % Elongation Ch, % 50% Mod Ch, %

-60

-50

-40

-30

-20

-10

0

10


Pro

per

ty C

han

ges

Swell, % Hardness Ch, pts Tensile Ch, % Elongation Ch, %

29 | P a g e

Zetpol polymers offer resistance to acids and alkalis used in oil field fluids. These are present in

most fluids for various operations from well bore drilling to well work-over. The acids and

alkalis are used to treat a specific condition in the well. Elastomers used in these harsh conditions

must have resistance to the additives in drill fluids. Zetpol polymers offer excellent resistance to

many fluids. An evaluation of the chemical resistance for Zetpol 2020 and 1020 demonstrates

excellent resistance to various acids and alkalis used in oil field service (Table 2). The Zetpol

2020 with the higher level of ethylene present in the polymer performs well next to Zetpol 1020.

The volume and hardness change stability for two Zetpol compounds display this performance

(Figures 25 & 26)

Sulfuric Acid H2O4S

Hydrochloric Acid HCl

Acetic Acid C2H4O2

Nitric Acid HNO3

Phosphoric Acid H3PO4

Sodium Hydroxide NaOH

Ammonium

Hydroxide NH4OH

Water

H2O

Table 2- Acids and Alkalis Evaluated

Figure 25- Volume Swell in Various Acids and Alkalis

-20

0

20

40

60

80

100

120

140

H2O4S HCl C2H4O2 HNO3 H3PO4 NaOH NH4OH H2O

Vo

lum

e S

we

ll, %

Z-2020 Z-1020

30 | P a g e

Figure 26- Hardness Change in Various Acids and Alkalis

Blow Out Preventers (BOP) There are two basic designs for blowout preventers--annular and

ram. Both types are used to control the fluids in the well. Blowout preventers are deployed in

stacks with at least one annular and two ram-type preventers. An annular blowout preventer sits

on top of this stack and is used to seal the annulus--the space between the drill pipe and the well

bore. The ram blowout preventers seal the well by activation of semi-circular steel halves. In

both blowout preventers, elastomeric compounds provide the seal to control the flow of the well

fluids. The compounds must provide excellent strength to hold the well pressure as well as

resistance to the various chemicals and fluids in the well.

Zetpol polymers offer an excellent selection for these demanding applications. Where extrusion

resistance is a necessity, Zetpol 2010H provides the required physical properties essential for this

service. Coupled with the excellent fluid resistance and wear properties Zetpol 2010H is an

excellent fit with these demanding applications. As for many down-hole applications compound

properties at evaluated temperatures are critical. The tensile and tear properties for Zetpol 2010H

demonstrate the performance at elevated temperatures (Figures 27 & 28).

-50

-40

-30

-20

-10

0

10

H2O4S HCl C2H4O2 HNO3 H3PO4 NaOH NH4OH H2O

Har

dn

ess

Ch

ange

, pts

.

Z-2020 Z-1020

31 | P a g e

Figure 27- Tensile Strength for Zetpol Compounds at Elevated Temperatures

Figure 28- Tear Strength for Zetpol Compounds at Elevated Temperatures

Packers There are several different packer designs for oil field service. The basic function for a

packer is to separate the annulus from drill stem during drilling and well production operations.

Packers seal against the casing to isolate sections of the well. A typical elastomer in this

application needs excellent strength, fluid resistance as well as abrasion and extrusion resistance.

Zetpol polymers perform well in tough applications offering excellent chemical and fluid

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Z-1020 Z-2010 Z-2010H Z-2020

Ten

sile

Str

en

gth

, Mp

a

23 100 150

0

5

10

15

20

25

Z-1020 Z-2010 Z-2010H Z-2020

Tro

use

r Te

ar S

tre

ngt

h, p

pi

23 100 150

32 | P a g e

resistance. A method to determine the resistance to extrusion in well environments is the API

Extrusion test. The Extrusion resistance for Zetpol compounds is illustrated in Figure 29. With

the drop in acrylonitrile level the extrusion resistance improved.

Figure 29- API Extrusion Resistance at 150C with 69 MPa Pressure

Stators and pump motors These applications are some of the most demanding, requiring

excellent toughness and abrasion as well as resistance to a wide range of fluids and chemicals

used during drilling and completion operations. These applications also require good dynamic

response to resist heat buildup during operations. Zetpol polymers offer a range of properties that

met these demanding requirements.

To demonstrate this ability several Zetpol compounds were evaluated for physical property

response at elevated temperatures. The tensile properties for Zetpol 2010 and 1010 are similar at

room temperature while the tensile strength for Zetpol 3310 is lower (Figure 30). As the

temperature is increased to 150C, all compound tensile strengths drop but the Zetpol 1010

retained a higher strength than the other two compounds (Figure 30). The tear properties for the

three compounds remained similar for all the temperatures (Figure 31).

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Z-1020 Z-2010 Z-2010H Z-2020

Ave

rage

mat

eri

al lo

ss, g

ram

s

33 | P a g e

Figure 30- Tensile Strength for Several Zetpol Compounds by ACN Level

Figure 31- Tear Strength for Several Zetpol Compounds by ACN Level

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Z-2010 Z-1010 Z-3310

Ten

sil

e S

tren

gth

, p

si

Room Temperature 100C 150C

0

50

100

150

200

250

300

350

Z-2010 Z-1010 Z-3310

pp

i

Tear Strength, Die C

Room Temperature 100C 150C

34 | P a g e

The dynamic properties for a compound can be influenced by many factors ranging from

polymer choices to fillers used to reinforce the compound. The other factor is how the tests are

conducted. There are many different methods to evaluate a compound for dynamic properties.

The method used for this evaluation was completed using a cured sample subject to a frequency

sweep at 150C. Hysteresis is the heat buildup and is relative to the compound tan . As the heat

builds up in the compound then the tan will increase. The dynamic properties for these three

Zetpol polymers are dependent on their acrylonitrile level (Figure 32).

Figure 32- Dynamic Response for Several Zetpol Compounds by ACN Level

Drill bit seals On the end of the drill string is the bottom-hole assembly consisting of many

different elements that provide assistance in drilling operations. At the end of this assembly is the

drill bit. Here the environment is the harshest for the well, only the toughest materials can

survive. Besides resistance to harsh chemicals, materials must have excellent abrasion resistance.

As the primary function of the bit is to cut through the rock, the materials must resist volume

swell to the drilling mud, which flushes the rock cutting to the surface.

0.000

0.100

0.200

0.300

0.400

0.500

1 10 100 1000 10000

Ta

n D

elt

a

Log Freq Sweep @ 150C

By ACN Level

Z-2010 Z-1010 Z-3310

35 | P a g e

A balance between tear, volume swell and abrasion resistance is important for drill bit seals. The

acrylonitrile level in the Zetpol polymer will affect the abrasion resistance for the compound.

The higher the acrylonitrile level the less the compound is resistant to abrasion. In order to help

in the selection of the proper polymers, compound properties for several Zetpol polymers show

their resistances to abrasion along with tear properties and resistance to swell in IRM 903. Zetpol

2010 exhibits the lowest abrasion lost as well as similar tear strength as the other Zetpol

compounds (Figures 33 & 34). The swell in IRM 903 oil is the highest with Zetpol 2010 and

2020, while the other three Zetpol compounds present lower swell values (Figure 35).

Figure 33- DIN Abrasion Loss for Zetpol Compounds

0

20

40

60

80

100

120

Z-0020 Z-1010 Z-1020 Z-2010 Z-2020

DIN

, mm

^3 L

oss

36 | P a g e

Figure 34- Tear Strength for Zetpol Compounds

Figure 35- IRM 903 Volume Swell for Zetpol Compounds

Rolls

Elastomer roll covers are used in a variety of functions. One common application is the removal

of liquids from paper pulp. The press roller in paper mills squeezes out excess water from

freshly formed sheets of paper. Likewise, rolls in the textile industry remove excess chemical

solutions and water. In the steel industry, rolls remove acids, bases and other liquids after

0

50

100

150

200

250

300

350

400

Z-0020 Z-1010 Z-1020 Z-2010 Z-2020

Tear

Str

en

gth

, pp

i

0

2

4

6

8

10

12

14

16

Z-0020 Z-1010 Z-1020 Z-2010 Z-2020

Vo

lum

e S

we

ll, %

37 | P a g e

processes such as cooling and etching. With modern paper mills running at production speeds

upwards of 120 km/hr, downtime for roll replacement is an expensive option. Metal rolls require

expensive, time-consuming regrinding to maintain desired roll dimensions, while rubber covered

rolls are more economical but require frequent replacement due to loss of crown and roll

softening due to aggressive solutions used for cleaning and the actual paper making process.

Zetpol polymers are resistant to many chemicals offering excellent heat and steam resistance. In

addition, HNBR compounds have excellent wear resistance and present outstanding dynamic

properties to counter heat buildup. Due to the ethylene content with Zetpol polymers, they are

resistant to many chemicals used in the roll industry offering excellent heat and steam resistance.

These polymer properties can be further enhanced with compounding providing an exceptional

product with longer life for the severe conditions encountered across the industry.

In roll applications requiring hardness greater than Shore A 80 and the highest level of abrasion

resistance, specially modified Zeoforte ZSC elastomers are available. In field use, Zeoforte-

covered rolls have provided improvements in service life in addition to improved physical

properties, resulting in less downtime for production and reducing overall operational costs.

Rolls may also be used to impregnate a web. Examples of this can be found in the size press roll

at paper mills where starch, pigments, and other chemicals are applied to a paper sheet. In textile

and printing operations, rolls apply dyes, inks, and other chemicals.

Dynamic properties are of utmost importance in paper and steel roll applications. It is important

for the roll cover to recover from the deformation in the nip within one rotation. Otherwise,

vibrations and loss of uniform crown may occur, causing paper quality and consistency to be

jeopardized. Heat buildup is also a significant concern. Rolls are usually cooled inside, but heat

generated in a rubber roll cover can only be slowly removed via the surface. Reducing heat

buildup is essential to maintaining the desired gap setting of the nip. Typically, as the roll

temperature increases, the gap setting becomes larger, resulting in varying product quality. This

is illustrated below in Figure 36.

38 | P a g e

Figure 36- Relationship between Roll Temperature and Gap Distance

An effective method for evaluating the hysteresis or heat buildup characteristics in elastomer

compounds is to compare their tan values as the hysteresis is directly related to the compound

tan . The lower the tan value the lesser amount of heat buildup will occur in the compound.

Many factors such as filler type and loading to the cross-link density affect the hysteresis in a

compound. Other factors such as polymer molecular weight, acrylonitrile level and saturation

level will affect the dynamic response. An evaluation of the dynamic response for several Zetpol

polymers demonstrates the relationship acrylonitrile has on the tan . As the acrylonitrile content

decreases, the tan response decreases (Figure 37). Additionally, increases in polymer molecular

weight decrease the tan response (Figure 38).

0

10

20

30

40

50

20 40 60 80

Gap

Dis

tan

ce, m

m

Roll Temperature, C

39 | P a g e

Figure 37- Frequency Sweep for Zetpol Polymers by Acrylonitrile Level

Figure 38- Frequency Sweep for Zetpol Polymers by Mooney Viscosity

0.000

0.100

0.200

0.300

0.400

0.500

1 10 100 1000 10000

Tan

Delt

a


Z-2010 Z-1010 Z-3310

0.000

0.100

0.200

0.300

0.400

0.500

1 10 100 1000 10000

Tan

Delt

a


Z-2010H Z-2010 Z-2010EP

40 | P a g e

An evaluation of a variety of carbon blacks, at the 50 part level, using a Zetpol 2010 compound

studied their impact on a number of properties. Typically, smaller partial size reduces the

abrasion loss but will affect the heat buildup in compounds. The Taber abrader illustrates the

relationship of particle size and material loss (Figure 39). The evaluation used an H22 wheel and

a one-kilogram weight. The samples were measured after 1000 revolutions.

Figure 39- Taber Weight Loss with Various Carbon Blacks

The dynamic response the carbon black has on compounds was measured using a spectrometer

by running a temperature sweep from 25C to 175C. The tan values decreased with increasing

filler size and increasing temperature. Selection of the proper carbon black will increase the

service life of rolls (Figure 40). A dynamic frequency sweep at 150C with Zetpol 2010 further

illustrates the response carbon black has on the compound tan (Figure 40).

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

N110 N231 N326 N330 N550 N660 N762 N774 N990

We

igh

t Lo

ss, g

ram

s

41 | P a g e

Figure 40- Dynamic Response for Zetpol 2010

Figure 41- Frequency Sweep for Zetpol Polymers by Carbon Black Type

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

N110 N231 N326 N330 N550 N660 N762 N774 N990

tan

de

lta

25C

100C

175C

0.000

0.100

0.200

0.300

0.400

0.500

1 10 100 1000 10000

Tan

Delt

a


N550 N990 N326

42 | P a g e


Processing

43 | P a g e

Processing Zetpol Compounds

Zetpol Compounding

A critical step in designing a compound to meet the application requirements is awareness of the

function of the rubber component. Understanding the environment for the application will help

in selection of the proper polymer and compound ingredient choices. Basic matters such as fluid

contact, temperature ranges and the dynamic or static nature of the application will influence

these polymer selections. Zeon offers an extensive range of Zetpol polymers to address the

variety design criteria.

Zetpol polymers are thermo-set elastomers requiring formulation of the polymer with other

ingredients to obtain the required final properties. In the rubber industry, mixing is commonly

called "compounding." A typical recipe is composed of Zetpol polymer, carbon black and/or

mineral filler(s), metal oxides, plasticizer, antioxidants, processing aids, and curatives. Selection

of these ingredients is based on desired compound properties and molding conditions.

Compounds are based on 100 parts of polymer. Below is a generalized formulation for a Zetpol

formulation:

Zetpol polymer(s) 100 phr

Fillers 20 250 phr

Plasticizer 0 30 phr

Metal Oxides 0 - 10 phr

Antioxidants 1 3 phr

Antiozonants 0 3 phr

Process aids 0 - 3 phr

Co-agents & Accelerators 0 40 phr

Curatives 0.5 12 phr

Table 3- Typical Loading for Ingredients in Zetpol Recipes

The following pages will give details for basic compounding of Zetpol polymers. With the wide

assortment of raw materials available today it is impossible to evaluate the performance for all of

44 | P a g e

these materials in Zetpol formulations. However, there are some raw materials which show

excellent performance in common recipes.

Polymers Today, Zetpol polymers can be formulated to meet many of the demanding

applications and temperature ranges. A critical first step is selecting the correct polymer for the

application and process. The ethylene groups in the polymer provide chemical, heat and ozone

resistance as well as the elasticity for the compound. The acrylonitrile groups affect the fuel and

oil resistance, provides high tensile strength and affects low-temperature properties, which must

be considered when selecting the polymer for the application. The butadiene provides a place for

cross-linking to ensure the best possible properties. Last, the Mooney viscosity of the polymer

must be selected to fit the required process.

Carbon Black Fillers The fillers selected should balance the required physical properties,

compound processability and product performance. Both black and non-black filler may be used

with Zetpol polymers. Carbon black fillers are the primary filler of choice for Zetpol compounds

with N774 or SRF types used more than others based on the intrinsic tensile strength of the

Zetpol polymers. Carbon black particle size and structure will influence the compound properties

such as hardness, tensile and elongation values. The size and structure of the carbon black will

also affect compound processability.

In a compound study using Zetpol 2010 with various carbon blacks at different loading levels

general trends on the relationship with compound properties were established. In this study five

different carbon blacks at three different loadings showed the differences on typical compound

properties. The carbon blacks evaluated in this study range from N110 to N990 giving iodine

values between 145 down to 9. The structure for these blacks used in the study span from very

low structure with N990 to a highly structured black such as N550.

Mooney viscosity is a leading indicator for processability with rubber compounds. A typical

viscosity measurement is evaluated at 100C with a one-minute preheat period followed by a

four-minute test. The Mooney viscosity is reported at the conclusion of the test. Typically, lower

viscosity compounds flow better than those with higher viscosities. In this evaluation using

Zetpol 2010 the smaller carbon black particle size and high structure carbon black increased the

viscosity, while the larger and smaller particle carbon black had the lowest viscosity (Figure 42).

45 | P a g e

Figure 42- Mooney Viscosity Relationship to Carbon Black Type and Loading

One typical property for many applications is the Shore A hardness. Generally with increased

carbon black loading the hardness increases in the compound. As the carbon black particle size

increases, the Shore A hardness will decrease (Figure 43). The structure of the carbon black does

not influence hardness. Below are the hardness values for the carbon blacks frequently used in

Zetpol compounds.

Figure 43- Hardness Relationship to Carbon Black Type and Loading

0

20

40

60

80

100

120

140

160

180

N110 N326 N550 N774 N990

Mo

on

ey

Vis

cosi

ty,

ML

1+4

@ 1

00

C

25 phr

50 phr

75 phr

0

10

20

30

40

50

60

70

80

90

100

N110 N326 N550 N774 N990

Har

dn

ess

Sh

ore

A, p

ts

25 phr

50 phr

75 phr

46 | P a g e

Carbon black particle size has the greatest effect on tensile properties in Zetpol compounds,

while the carbon black structure does not appear to impact overall tensile properties (Figure 44).

The smaller particle size of N110 offers the highest tensile values, while N990 offers the lowest.

Still the lowest tensile value is above 15 MPa, testament to the excellent strength properties of

Zetpol polymers. The modulus values on the other hand do show a relationship with the carbon

black structure. The highest structure carbon black used for this study has the highest 100%

modulus values (Figure 45).

Figure 44- Tensile Relationship to Carbon Black Type and Loading

0

5

10

15

20

25

30

35

40

N110 N326 N550 N774 N990

Ten

sile

, Mp

a

25 phr

50 phr

75 phr

47 | P a g e

Figure 45- 100% Modulus Relationship to Carbon Black and Loading

Maintaining compound flexibility in many applications can require meeting particular elongation

requirements. As carbon black is a principal choice for many applications, elongation values can

differ by carbon black loading, filler size and the structure. Larger particle sizes can have higher

elongation values due to lower filler interaction but a smaller particle carbon black can attain

elongation values above 350% (Figure 46).

Figure 46- Elongation Relationship to Carbon Black Type and Loading

0

2

4

6

8

10

12

14

N110 N326 N550 N774 N990

10

0%

Mo

du

lus,

MP

a

25 phr

50 phr

75 phr

0

50

100

150

200

250

300

350

400

450

500

N110 N326 N550 N774 N990

Elo

nga

tio

n, %

25 phr

50 phr

75 phr

48 | P a g e

Toughness is required in many applications such as the demanding oil field markets. Zetpol

compounds provide solutions in these demanding applications daily. As noted with tensile

properties for Zetpol compounds, tear strength is affected by the carbon black loading as well as

particle size and the structure. The higher load of carbon black increased the tear strength for the

compounds. Smaller carbon black particle size or larger structure will provide the best tear

resistance in the most demanding applications (Figure 47).

Figure 47- Tear Resistance Relationship to Carbon Black Type and Loading

Many Zetpol compounds are used to seal aggressive fluids in applications where excellent

compression set resistance is required. For this evaluation the compression set properties for the

Zetpol compounds were evaluated using a standard molded button in a hot air environment for

70 hours. The compounds were compressed 25% and the data reported reflects the amount of set

the compound retained, expressed as a percentage of the original button height. Generally, as the

carbon black particle size increases, the compression set values decrease (Figure 48).

0

50

100

150

200

250

300

N110 N326 N550 N774 N990

Tear

Die

C, p

pi

25 phr

50 phr

75 phr

49 | P a g e

Figure 48- Compression Set Relationship to Carbon Black Type and Loading

The resistance to abrasion can be critical in some applications. It is critical for optimal abrasion

resistance that the correct filler/s be selected for peak performance. In this evaluation of carbon

blacks abrasion performance, the Tabor abrader with a one-kilogram weight and the H22 wheel

were used. After 1000 revolutions the compound weight loss was measured. Generally, the larger

carbon black particles increased the weight loss as did the increased carbon black loading (Figure

49).

Figure 49- Abrasion Resistance Relationship to Carbon Black Type and Loading

0

5

10

15

20

25

30

35

40

45

N110 N326 N550 N774 N990

Co

mp

ress

ion

Se

t, 7

0h

rs/

15

0C

, %

25 phr

50 phr

75 phr

0

0.02

0.04

0.06

0.08

0.1

0.12

N110 N326 N550 N774 N990

Tab

er

Ab

rasi

on

, H2

2, 1

00

0 R

ev,

1 k

g

25 phr

50 phr

75 phr

50 | P a g e

Non-black Fillers Many Zetpol applications require non-black compounds. This is accomplished

by using white filler such as silica. An evaluation of eight different non-black fillers in Zetpol

2010 shows the relationship of compound properties to these filler systems. The compounds are

based on 40 parts of filler using a peroxide cure system. A silane coupling agent was used for

these compounds. The non-black fillers used for this evaluation are listed in the table below.

Chemical

name

Hydrophilic

fumed

silica

Untreated

fumed

silica

PDMS

treated

fumed

silica

Synthetic

amorphous

silicon

Synthetic

amorphous

silicon

Precipitated

silica

Synthetic

sodium

aluminosilicate

Magnesium

silicate

Abbreviation

used HFS UFS PTFS SAS-1 SAS-2 PS SSA MS

Table 4- Non-black Fillers used in Zetpol Compound Evaluation

Like the carbon black compounds noted earlier, processability is essential for an optimized

compound. In this non-black filler evaluation with Zetpol 2010 the Mooney viscosity is generally

higher than a Zetpol compound with a similar carbon black filled compound. The

polydimethylsiloxane treated fume silica has a lower viscosity than the untreated fume silicas

(Figure 48). The synthetic amorphous fillers differ by particle size. The SSA-2 is smaller than

the SSA-1. The Mooney viscosity for the larger particle size shows a grater viscosity (Figure 50).

This evaluation shows that magnesium silicate is the lowest viscosity compound.

Figure 50- Mooney Viscosity Relationship to Non-black Fillers

0

20

40

60

80

100

120

140

160

180

HFS UFS PTFS SAS-1 SAS-2 PS SSA MS

Mo

on

ey

visc

osi

ty,

ML

1+4

@1

00

C

51 | P a g e

The hardness relationship with the non-black fillers is similar to an equally filled carbon black

loaded compound. The untreated fume silica has the highest Shore A hardness, while the

synthetic sodium aluminosilicate is the lowest hardness (Figure 51).

Figure 51- Hardness Relationship to Non-black Fillers

Many Zetpol applications have requirements for excellent tensile strength. Non-black

compounds are no different in their ability to satisfy this requirement. With the evaluations with

Zetpol 2010 the hydrophilic and untreated fume silicas excelled in generating a high strength

compound, while the synthetic sodium aluminosilicate had the lowest tensile value (Figure 52).

Most compounds were above 20 MPa, with five compounds above 25 MPa tensile strength.

However, the 100% modulus was very similar with the exception of the magnesium silicate.

Here the modulus for this compound was almost twice as great as the remaining non-black fillers

(Figure 53).

55

60

65

70

75

80


Sho

re A

har

dn

ess

, pts

.

52 | P a g e

Figure 52- Tensile Relationship to Non-black Fillers

Figure 53- 100% Modulus Relationship to Non-black Fillers

The flexibility of the non-black fillers in Zetpol compounds is similar to carbon black filled

compounds. Mineral filled Zetpol compounds gave elongation values above 300% with several

above 400%. The smaller particle size synthetic amorphous silica had the lowest elongation

values, while the magnesium silicate had the highest elongation value (Figure 54). The

elongation for the compound filled with the precipitated silica was lower than the three

compounds with fumed silica.

0

5

10

15

20

25

30

35

40


Ten

sile

, Mp

a

0

1

2

3

4

5

6


10

0%

Mo

du

lus,

Mp

a

53 | P a g e

Figure 54- Elongation Relationship to Non-black Fillers

The tear strength for the non-black fillers was lower than the similar compounded carbon black

fillers with the exception of the N990 carbon black. With the N990 filled compounds the results

were similar to the non-black filled compounds. Of the non-black fillers, the synthetic sodium

aluminosilicate was the lowest tear strength (Figure 55). All the fumed silicas and the

magnesium silicate were similar in strength.

Figure 55- Tear Strength Relationship to Non-black Fillers

0

100

200

300

400

500

600


Elo

nga

tio

n, %

0

50

100

150

200

250


Tear

Die

C, p

pi

54 | P a g e

As a measure of heat resistance, compression set properties for the non-black fillers closely

follow the pH for the filler used. The hydrophilic fumed silica set is double the compression set

of magnesium silicate (Figure 56). The more basic the filler used in the compound, the better the

heat resistance. This relationship of the pH is seen in extended aging studies with Zetpol 2000

where elongation retention after aging is improved with usage of these types of highly basic

fillers (Figure 57).

Figure 56- Compression Set Relationship to Non-black Fillers

Figure 57- Arrhenius Plot to 50% Elongation Loss with Zetpol Polymers

0

10

20

30

40

50

60

70


Co

mp

ress

ion

Se

t, 7

0 h

rs/

15

0C

, %

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

100 110 120 130 140 150 160 170 180

Log

Tim

e, h

ou

rs

Temperature, C

ZP 2010 / perox / black ZP 2000 / perox / black

ZP 2000 / perox / non-black

55 | P a g e

Plasticizers Plasticizers are commonly used in Zetpol compounds to adjust the hardness, improve

the low-temperature performance or to balance the swell characteristics for the compound. The

processability of a Zetpol compound can be improved with the usage of plasticizers. However,

extreme loading levels will have negative effects on compound performance thus a balance of

compound properties and processability by other methods.

Given the fluid resistance with Zetpol polymers, knowing the saponification value for a given

plasticizer helps in optimization of compound performance. With the varied acrylonitrile level

for Zetpol polymers, knowing the chemical compatibility of the plasticizer is critical. For Zetpol

polymers with a low acrylonitrile level, plasticizers with a lower saponification value work best.

Likewise Zetpol polymers with a higher acrylonitrile level work best with plasticizers with a

higher saponification value. The table below can help in selection of the proper plasticizer with

the corresponding acrylonitrile level.

ACN Level Saponification value Plasticizer Types

44% or greater Greater than 350 Polyglycol Diesters

Polymeric Polyesters

36% 275 to 350 Aromatic Di- and Tri- esters

Polymeric Resins

At or below 25% Less than 275 Aliphatic Diesters

Table 5- General Plasticizer Types for use with Zetpol Polymers

In a study using three different plasticizers at two loading levels, the effects on compound

properties for a Zetpol 2010 were evaluated. The plasticizers used in the Zetpol compound were

a dibutoxyethoxyethoxyethyl glutarate (DEEEG), trioctyl trimellitate (TOTM) and mixed dibasic

polyester (Polymeric Polyester). Each plasticizer was evaluated at 10 and 20 parts.

The plasticizers do have an effect on the compound Shore A hardness. In the Zetpol 2010

compound those loaded with 10 parts of each plasticizer showed a nominal change in hardness

(Figure 58). However, with both the DBEEEG and TOTM plasticizers at the higher plasticizer

loading, these compounds saw a reduction in hardness. The DBEEEG compound hardness was

reduced by 13 points and 8 points for the TOTM compound (Figure 56).

56 | P a g e

Figure 58- Plasticizers Effects on Hardness Values

The tensile properties for these compounds showed the general trend of decreased strength and

increased elongation with increased plasticizer loading. The tensile strength for the DBEEEG

plasticizer was lower than the others at both loadings (Figure 59). The polymeric polyester

shows the least response to increased plasticizer loading on tensile strength (Figure 59). The

100% modulus values were all depressed with each plasticizer at each loading (Figure 60).

Again, the polymeric polyester saw the least response to increased plasticizer loading (Figure

60). The elongation values for the TOTM and polymeric polyester remained reasonably stable at

both loadings while the DBEEEG shows a larger difference with increased plasticizer loading

(Figure 61).

0

10

20

30

40

50

60

70

80

Har

dn

ess

, pts

57 | P a g e

Figure 59- Plasticizers Effects on Tensile Values

Figure 60- Plasticizers Effects on 100% Modulus

0

5

10

15

20

25

30

Ten

sile

, Mp

a

0

1

2

3

4

5

6

7

8

9

10

0%

Mo

du

lus,

Mp

a

58 | P a g e

Figure 61- Plasticizers Effects on Elongation Values

The volatility of these plasticizers was measured by evaluating the compound compression set

for 168 and 504 hours at 150C in hot air. The compression set increased with both the DBEEEG

and polymeric polyester (Figure 62). The TOTM plasticizer remained very stable at both loading

levels for the test period (Figure 62). The extractability for the plasticizers was measured by

aging the compounds in IRM 903 for 168 and 504 hours at 150C. In all cases, the plasticizers

lower the initial swell (Figure 63). As the aging continued for the compounds, the volume swell

increased in each compound (Figure 63).

0 50

100 150 200 250 300 350 400 450 500

Elo

nga

tio

n, %

59 | P a g e

Figure 62- Plasticizers Effects on Compression Set Performance

Figure 63- Plasticizers Effects on IRM 903 Volume Swell

Metal Oxides The usage of certain metal oxides in Zetpol compounds will improve the heat

resistance performance. An evaluation using zinc oxide, magnesium oxide and calcium oxide

with Zetpol 2010 studied their effects on heat resistance as measured by compression set and

elongation retention after aging the compound at 150C. Each metal oxide was evaluated at five

parts in a peroxide compound.

0 10 20 30 40 50 60 70 80

Co

mp

ress

ion

Se

t, %

168/150 504/150

0 2 4 6 8

10 12 14 16

Vo

lum

e S

we

ll, %

168/150 504/150

60 | P a g e

The basic tensile properties demonstrate improvements in compound properties with the addition

of metal oxides. The zinc oxide displayed the greatest increase in 100% modulus (Figure 64).

This trend carried over in the tensile properties for the zinc oxide compound (Figure 65).

However, all three compounds demonstrated increased tensile strengths (Figure 65). The

magnesium and calcium oxides exhibited higher elongation values while the zinc oxide reported

the lowest value (Figure 66).

Figure 64- Effects of Metal Oxides on 100% Modulus

0

1

2

3

4

5

6

None ZnO MgO CaO

10

0%

Mo

du

lus,

Mp

a

61 | P a g e

Figure 65- Effects of Metal Oxides on Tensile Properties

Figure 66- Effects of Metal Oxides on Elongation Properties

The aging performance was greatly improved by using metal oxides in Zetpol compounds. The

zinc and magnesium oxides outperformed the calcium oxide both for compression set resistance

and in elongation retention (Figures 67 & 68). The zinc oxide excels in compression set

resistance even after 504 hours at 150C in hot air environments (Figure 67). The magnesium

oxide retains excellent flexibility after 504 hours in hot air at 150C (Figure 68).

0

5

10

15

20

25

30

None ZnO MgO CaO

Ten

sile

, Mp

a

0

50

100

150

200

250

300

350

400

450

500

None ZnO MgO CaO

Elo

nga

tio

n, %

62 | P a g e

Figure 67- Effects of Metal Oxides on Compression Set Response at 150C

Figure 68- Effects of Metal Oxides on Elongation Changes at 150C

Antioxidants Today, there are many options for antioxidants to use in rubber compounds. These

ingredients are needed to protect the polymer from premature degradation. There are two basic

ways for antioxidants to slow the oxidation. One method is to stop the attacking free radicals

before they confront the hydrogen atoms on the polymer. Amine and phenolic antioxidants work

this way in rubber compounds. Another class of antioxidants attacks the free radical before they

can spread. Phosphite and thioester antioxidants carry out this form of protection.

0

10

20

30

40

50

60

None ZnO MgO CaO

Co

mp

ress

ion

Se

t, %

168 hours 504 hours

-80

-70

-60

-50

-40

-30

-20

-10

0

None ZnO MgO CaO

168 hours 504 hours

63 | P a g e

Many different antioxidants are used in Zetpol compounds. Some perform better than others and

Zeon found that a blend of 4, 4' -Bis (alpha, alpha-dimethylbenzyl) diphenylamine and Zinc 2-

mercaptotoluimidazole offer the best performance in many modern applications. In an evaluation

using eight different antioxidants the performance as a protection system in Zetpol compounds is

shown below in Table 6.

2, 2, 4- Trimethyl- 1,2-dihydroquinoline

4, 4' -Bis (alpha, alpha-dimethylbenzyl) diphenylamine

mixed diaryl p-phenylenediamine

mixed zinc antioxidant & diphenylamine

2-mercaptotoluimidazole

Zinc 2-mercaptotoluimidazole

Styrenated diphenyl amine

Zinc 4- and 5-methylmercaptobenzimidazole

Table 6- Antioxidants Used in Zetpol Compounding

The compounds used in the study are based on Zetpol 2010. The usage of some antioxidants can

affect the cure response in Zetpol compounds. With peroxide cure systems the ODR MH values

can be suppressed by using amine-type antioxidants (Figure 69). This is due to the drop in the

cross-link density and can be adjusted by increasing the peroxide level slightly in the compound.

64 | P a g e

Figure 69- Cure Response in Zetpol 2010 with Various Antioxidants

Many applications require compounds to remain stable after heat aging. This is measured in

many ways including studying the change in compound properties after aging. The typical

properties studied are hardness, tensile and elongation change and compression set

properties. Below in Figure 70, the evaluation of the various anti-oxidants effect on hardness

change after ageing a Zetpol 2010 compound in air at 150C. The blend of the 4, 4' -Bis

(alpha, alpha-dimethylbenzyl) diphenylamine and Zinc 2-mercaptotoluimidazole provide

good hardness stability.

0

20

40

60

80

100

120

140

OD

R M

H @

17

0C

, lb

f-in

65 | P a g e

Figure 70- Hardness Change in Zetpol 2010 with Various Antioxidants

The heat resistance performance for Zetpol compounds is enhanced with the addition of

antioxidants. The protection offered by the various antioxidants greatly depends on the method

of the particular antioxidant for Zetpol compounds. The amine type anti-oxidants and dazoles

provide better tensile retention than the quinoline antioxidant, overall, this trend continuous with

elongation retention (Figures 71 & 72). However, the mixed diphenylamine does show a greater

loss in elongation after 168 hours than the remaining antioxidants evaluated.

Figure 71- Tensile Change in Zetpol 2010 with Various Antioxidants

0

2

4

6

8

10

12

14

Har

dn

ess

ch

ange

, pts

.

70 hrs/ 150C 168 hrs/ 150C

-30

-25

-20

-15

-10

-5

0

Ten

sile

ch

ange

, %

70 hrs/ 150C 168 hrs/ 150C

66 | P a g e

Figure 72- Elongation Change in Zetpol 2010 with Various Antioxidants

The performance of Zetpol compounds in sealing applications requires excellent resistance to

compression set. The antioxidants in this study measured their effectiveness after 70 hours at

150C. Most of the antioxidants reported compression set values below 20%, only the mixed

diphenylamine reported a compression set value above 35% (Figure 73).

Figure 73- Compression Set Response after 70 hours at 150C with Zetpol 2010 with

Various Antioxidants

-70

-60

-50

-40

-30

-20

-10

0

Elo

nga

tio

n c

han

ge, %

70 hrs/ 150C 168 hrs/ 150C

0

5

10

15

20

25

30

35

40

Co

mp

ress

ion

se

t, %

67 | P a g e

Process Aids Zetpol compounds may use process aids to enhance the flow of the compound or to

aid in release during molding operations. There are many different chemicals available for use as

process aids with the predominant type being a fatty acid derivative. Generally, these process

aids will not greatly affect compound properties but some are known to have adverse effects on

heat aging performance. Mold fouling is known to increase with high loadings of process aids,

thus finding an optimal balance between processability and properties is critical with Zetpol

compounds.

Using a peroxide cured Zetpol 2010 compound a selection of process aids was evaluated to

measure their response on flow properties as well as physical and aged properties. The process

aids were missed at two levels, one and three parts. The process aids used for the study are listed

in the table below.

Chemical name Designated

Pentaerythrityltetra stearate PES

Microcrystalline wax Micro wax

Erucamide Erucamide

Fatty acid Fatty acid

Fatty acid esters FA esters

Organosilicone additive Organosil

Table 7- Process Aids

The Mooney viscosity for the Zetpol compounds was reduced with the addition of the process

aids. The pentaerythrityltetra stearate and microcrystalline wax caused the greatest reduction in

viscosity (Figure 74). The same trend with pentaerythrityltetra stearate and microcrystalline wax

was demonstrated by the capillary rheometer with the compounds with three parts loading

(Figure 75). However, all the process aids evaluated caused a reduction in viscosity. The

capillary was run at 105C using a 1 mm die and 2.8 MPa force applied to the compound.

68 | P a g e

Figure 74- Effect of Process Aids on Mooney Viscosity

Figure 75- Effect of Process Aids on Capillary Rheometer

The process aids effect on physical properties was the greatest on elongation. In most cases the

elongation increased with the increased loading for the process aids. Only the organosilicone

additive remained steady (Figure 76). The retention of flexibility after aging the compounds in

an air oven at 150C was best with the microcrystalline wax (Figure 77). In general, the fatty

acid had the poorest retention of elongation properties. However, the trend with the fatty acid

process aid did not carry over in the compression set testing. Here all the process aids were

0.0

20.0

40.0

60.0

80.0

100.0

120.0

Mo

on

ey

Vis

cosi

ty,

ML

1+4

@1

00

C

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Vis

cosi

ty, P

a/se

c, 1

mm

die

69 | P a g e

generally higher than the control (Figure 78). The lower levels trended to perform better than

higher levels.

Figure 76- Process Aid Effect on Elongation Properties

Figure 77- Elongation Change as Affected by Process Aids

0

50

100

150

200

250

300

350

400

Elo

nga

tio

n, %

-70

-60

-50

-40

-30

-20

-10

0

Elo

nga

tio

n C

han

ge, %

168 elong 504 elong

70 | P a g e

Figure 78- Compression Set Reaction to Process Aids

Co-agent/Accelerators Co-agents and accelerators are used in many Zetpol compounds for a

number of reasons. The primary reason may be to change the cure rate in a compound to fit a

process, other reasons such as reduction in cure time and lowering compound viscosity are

additional typical uses for these ingredients. At high loadings, liquid co-agents work well in

reducing the compound viscosity and the scorch protected co-agents can improve the scorch

safety in a Zetpol compound.

In peroxide cure systems, co-agents add to the overall performance of Zetpol compounds by

increasing the number of chemical cross-links in the compound. Enhancements with physical

properties are improved with increases in modulus values. With the large variety of different co-

agents available, those that provide the best performance in Zetpol compounds are the di- and tri-

functional co-agents. Either by themselves on in blends these co-agents offer the best balance

for processability improvement and overall physical properties.

Chemical Name Abbreviation

N,N'-m phenylene dimaleimide PDA

poly-Butadiene PB

gylocldimethacrylate G-diM

trimethacryl

Documents

Zetpol Technical Manual