may 13, 2015cancarb 1. may 13, 2015cancarb 2 thermax ® thermal carbon black thermax ® vs. furnace...
TRANSCRIPT
April 18, 2023Cancarb1
April 18, 2023Cancarb2
• Thermax® Thermal Carbon Black
• Thermax® vs. Furnace Black
• The Thermax Advantage• Natural Rubber • Nitrile Rubbers• Hydrogenated Nitrile• Polychloroprene• Fluoroelastomers• NBR/PVC Blends• Ethylene Propylene Rubbers• Chlorosulfonated Polyethylene Rubbers – CSM• Butyl and Halobutyl Rubbers
• Questions & Answers
Overview
April 18, 2023Cancarb3
• Carbon black can be broadly defined as very fine particle aggregates of carbon, possessing an amorphous quasi-graphitic molecular structure
• The most significant areas of distinction between thermal black and furnace black are particle size and structure
• Thermax®, thermal carbon black, due to its higher particle size (280 nm) and lower structure, compared to even the most coarse furnace black, can be translated into excellent rubber compound properties
Thermax®
April 18, 2023Cancarb4
Particle Size Diameter
N110(15nm)
N762(80nm)
N990(280nm)
Thermax® vs. Furnace Black Grades
April 18, 2023Cancarb5
Low Structure Moderate Structure High Structure
N990 N762 N550
Thermax® vs. Furnace Black Grades
April 18, 2023Cancarb6
N762N774
N539
N660
N326
N330
N339
N343 N121
N220 N110
N990
N650 N550
0
20
40
60
80
100
120
140
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
NITROGEN SURFACE AREA (m2/g)
DECREASING PARTICLE SIZE
OA
N (
DB
P)
AB
SO
RP
TIO
N (
ml/
10
0g
)
INC
REA
SIN
G S
TR
UC
TU
RE
The Carbon Black Spectrum
April 18, 2023Cancarb7
Rubber PropertyAs Particle size
IncreasesAs Structure Decreases
Mixing temp.
Dispersion
Viscosity
Green Strength
Extrusion Quality
Scorch Safety
Influence of Carbon Black on Properties
April 18, 2023Cancarb8
Rubber PropertyAs Particle size
IncreasesAs Structure Decreases
Tensile
Elongation
Hardness
Tear resistance
Compression set
Heat build up
Abrasion resistance
Resilience
Influence of Carbon Black on Properties
April 18, 2023Cancarb9
The properties of Thermax® can be translated into rubber compounds with:
• Lower heat build-up, especially during extrusion, which is very important for halogen bearing rubbers and high hardness compounds
• Low hysteresis loss in dynamic applications, for example; automotive engine mounts
• Reduced volume swell in aggressive fluids
• Reduced cost
• Low compound viscosity which is essential for injection molded and sponge compounds
The Thermax® Advantage
April 18, 2023Cancarb10
– CH2 – C = CH – CH2 –
-CH2 CH2-
CH3 H
C=C
Natural Rubber Structure
CH3
• Natural rubber is polyisoprene
• There are four possible isomers of natural rubber
cis–1,4 Isomer
• 1,4 structure means that ‘C’ atoms 1 and 4 are joined in forming the chain
• In the cis-1,4 structure both carbon atoms 1,4 forming the chain are on the same side of the double bond
Natural Rubber (NR)
April 18, 2023Cancarb11
• Natural Rubber has outstanding mechanical properties and fatigue resistance making it a very popular choice in dynamic applications
• Natural rubber consists of polymer chains all having almost 100% perfect cis–1,4 structure. The true chemical name for this polymer is in fact, cis-1,4-polyisoprene
• When the units in a macromolecule all consist of the same molecule, the polymer is said to be stereo regular
Natural Rubber (NR)
April 18, 2023Cancarb12
Natural Rubber:• Crystallizes on stretching, resulting in:
• high gum tensile strength• high tensile strength/elongation @ break• very high tear strength & hot tear resistance• excellent De Mattia cut growth resistance
• Gives a glass transition temp (Tg) of approximately -75°C
• Has high resilience
• Has excellent tack & green strength properties• Imparts low damping (hysteresis) and low heat build-up in
dynamic deformation
• Is unsaturated (double bonds), resulting in poor resistance
to:• Heat aging• Ozone• Oils and hydrocarbons
Properties of Natural Rubber (NR)
April 18, 2023Cancarb13
Common Applications of Natural Rubber are:
• Truck tire tread (Tear, hot tear, low heat build-up)
• Passenger radial (Flexibility, low heat build-up)
• Anti-vibration (Dynamic deformation)
• Conveyor belting (High mechanical properties, tear)
• Adhesive tapes and solutions (Tack)
Applications of Natural Rubber
April 18, 2023Cancarb14
• Thermax® maintains the inherent good dynamic properties of the natural rubber polymer• The best choice for anti-vibration applications
• Thermax® lowers compound hardness while retaining the good tack properties inherent to natural rubber• Excellent for cushion gum compounds
• In wiper blade applications, higher loadings of Thermax® lower the rubber content of the compound which is essential for low noise and a good surface finish.
The Thermax® Advantage in Natural Rubber Compounds
April 18, 2023Cancarb15
SMR 100 100Zinc Oxide 3 3Stearic acid 1 1A.O. TMQ 1.5 1.5N 762 15 15Thermax N990 45 70Aromatic Oil 15 15CBS 3 3TMTD 0.5 0.5Sulfur 0.5 0.5
Cure time @ 160°C 11‘ 11‘Hardness 43 49Tensile strength 206 178Elongation @ Break % 535 480
Dynamic testing at 20 Hz Tan Delta at 25°C 0.084 0.027
Natural Rubber Engine Mount
NR Compound Example Using Thermax®
April 18, 2023Cancarb16
Nitrile Structure
Nitrile Rubber (NBR)
- CH2 - CH = CH - CH2 -
CN
acrylonitrilebutadiene
Polymer Unit
- CH2 - CH -+
( ) - (CH2 - CH = CH - CH2)n -
CN
CH2 - CH
m
-
April 18, 2023Cancarb17
• Nitrile rubbers are high molecular weight copolymers of 1,3-butadiene and acrylonitrile
• The percentage of acrylonitrile content can be varied from 18% to 50%, and will influence the performance characteristics of the polymer
• The great variation in acrylonitrile content possible with nitrile rubber, allows for compounds to be customized to highlight specific required properties
Nitrile Rubber (NBR)
April 18, 2023Cancarb18
Heat – aging resistance
Abrasion resistance
Tensile
Stiffness
Thermoplasticity
Compatibility with polar polymers
Oil/fuel resistance
Cure rate – Sulphur Cure System
Processability
Density
Increases
Air/gas permeability
Low temperature flexibility
Cure rate – peroxide system
Resilience
Decreases
Nitrile Rubber – Effect of Acrylonitrile Content
As ACN Increases
April 18, 2023Cancarb19
Decreases
Compression set
Porosity
Modulus
Green strength
Mill shrinkage
Sheet formation time on mill
Mixing temp
Acceptance of fillers/plasticizers
Incorporation time of fillers
Increases
Nitrile Rubber – Effect of Mooney
As Mooney Increases
April 18, 2023Cancarb20
Nitrile Rubber:
• Has very good oil and fuel resistance
• Can perform over a wide temperature range
• Has inherently good resistance to gas permeation which increases as the level of acrylonitrile increases
• Can be blended, up to 50%, with polyvinyl chloride (PVC) to produce compounds that exhibit good weathering characteristics in addition to good dynamic properties
• Can be co-polymerized with methacrylic or acrylic acid to produce carboxylated nitrile (XNBR), which is noted for its excellent dynamic properties and abrasion resistance
Properties of Nitrile Rubbers
April 18, 2023Cancarb21
Common Applications of Nitrile Rubber are:
• Gaskets and seals – NBR, XNBR (for high hardness)
• Hoses – NBR (mainly in tubes), NBR/PVC (mainly in covers)
• Belting – NBR
• Rollers – NBR, XNBR (for high hardness)
• Cable Jackets – NBR/PVC
• Textile (spinning cots/aprons) – NBR, NBR/PVC, XNBR
• Industrial footwear – NBR, NBR/XNBR blend, NBR/PVC sponge
• Insulation – NBR/PVC sponge
• Molded/extruded components for various industries & automotive
• Fabric proofing – NBR
• Milking inflation - NBR
Applications of Nitrile (NBR)
April 18, 2023Cancarb22
• Higher loadings are achievable with Thermax®, which reduces the rubber content enabling for lower swell in aggressive fluids• Gaskets and seals
• Thermax® promotes good extrusion properties and low heat development, avoiding potential scorch problems. This is critical for high hardness compounds• Hydraulic hose tubing
• Thermax® maintains the desired hardness of a compound while lowering the viscosity for effective blowing• NBR/PVC Sponge Insulation, hoses and soles
The Thermax® Advantage in NBR Compound Applications
April 18, 2023Cancarb23
Nitrile Rubber 100 (33-34% ACN, 75-80 Mooney)ZnO 5St. acid 1Processing Additive 2A.O. Aminox 2 (DPA + Acetone reaction product)A.O. ZMBI 2 (Zn Salt of 2 – Mercaptobenzimidazole)N550 50 Suitable blend for good processing,
N990 50 vulcanizate properties and good heat ageing Paraplex G-25 10 KP 140 10 Sulfasan R 1CBS 3TMTD 3Cure @ 166° 15'SH / TS / EB 70 / 152 / 270Vol. swell % 19 (ASTM Oil 3 / 70h 135°C)
Blending with Thermax N990 helps improve scorch safety during extrusion due to lower heat development. Higher filler loading improves over all extrusion properties and sealing with end couplings
Hydraulic Hose (Broad Temperature Range)
Blend of polyester and phosphate plasticizers for resistance to heat extraction and low temperature cracking
Nitrile Compound Example Using Thermax®
>>
April 18, 2023Cancarb24
HNBR Range
% Hydrogenation % ACN content Mooney (ML 1+4 @ 100°C) ~ 85 to 99+ 17 to 50 50 to 150
Hydrogenated nitrile rubber is based on NBR that has been chemically altered (hydrogenated), resulting in a much lower amount of unsaturation in the polymer backbone. HNBR exhibits significantly improved heat resistance, compared to NBR, while retaining excellent oil and fuel resistance.
Hydrogenated NBR (HNBR)
April 18, 2023Cancarb25
Mooney (ML 1+4 @ 100°C) 43 86
Hardness (Shore A) 68 76
T.S. (M.Pa) 17.5 21.9
EB (%) 390 180
Tear Die C (KN/m) 15 16.7
Comp. Set % (168h/150°C) 18 27
Abrasion (DIN mm3 loss) 145 260
Air Ageing (168h/150°C)
Hardness +8 +17
T.S. (%) Nil Brittle
EB (%) -30 Brittle
The significant improvements in the properties of HNBR over NBR, especially in compression set & heat ageing, bring HNBR very close to specialty rubbers.*ML 1+4@125oC
**ML 1+4@100oC
NBR+ 50 phr FEF 99+ % hydrogenation
38% ACN 55* Mooney
38% ACN50** Mooney
Comparison with NBR for 50 phr FEF compound-Peroxide cured
HNBR+ 50 phr FEF
April 18, 2023Cancarb26
HNBR* ACM FKM VMQ
Tensile 1 3 3 7
Heat Resistance 3 3 1 1
Comp. Set 2 2 1 1
Low Temp 3 5 7 1
Gear Oil 1 1 4 7
ASTM Oil #1 1 3 4 7
Sour Gasoline 2 5 1 7
Rating:1 Best; 7 Worst
*99+ % Hydrogenation
Hydrogenated NBR (HNBR)
April 18, 2023Cancarb27
• Timing belts (automotive) – ozone resistance, flexing • Power steering rotary shaft seals
• ‘O’ rings
• Oil well specialties
• Rollers
• Air conditioning hoses for cars
Applications of HNBR
April 18, 2023Cancarb28
• HNBR rubbers have inherently good mechanical properties and do not require a reinforcing black. Thermax® maintains the good mechanical properties of HNBR while lowering the compound viscosity which is essential for easy processing
• Thermax® does not degrade the excellent compression set of the HNBR polymer
• Higher loadings are possible with Thermax® resulting in lower polymer content which provides lower oil swell and a significant reduction in the overall compound cost
• Thermax® allows for extrusion with lower heat build-up giving better scorch safety and further improved impermeability of HNBR
The Thermax® Advantage in HNBR Compounds Applications
TORNAC A 38.55 (99.5% saturation) 100Thermax® N990 50Plasticizer WB 300* 5ZnO 5Stearic acid 1Trigonox 101-45** 8TAIC 3ML 1+4 @ 100°C 70MS Mooney Scorch at 125°C >25 ‘Cure time at 180°C 9’SH/TS/EB 60/146/235Air aging 150°C / 168H +8/-3/-40%Compression Set 70 h / 150°C 12
Thermax® maintains good low compression viscosity/mold flow, allows for less polymer content, low swell, adequate tensile strength and excellent compression set*Mixture of Aliphatic / Aromatic polyesters
** 2,5 dimethyl – 2,5 bis (tert butyl peroxy) hexane (Akzo).
Low Compression Set HNBR SealHNBR Compound Example Using Thermax®
April 18, 2023Cancarb29
Low Compression Set Seal
NBR/PVC Blends
• Both NBR and PVC are polar which makes them very compatible, typically a 70/30 ratio
• NBR provides resistance to heat and organic fluids but has poor resistance to weathering and ozone due to unsaturation.
• PVC provides resistance to weathering, ozone and aliphatic hydrocarbons oils
• PVC also improves processing, reduced flammability and mechanical properties such as T.S., tears and abrasions
April 18, 2023Cancarb30
Carboxylated NBR (XNBR)
• Carboxylated NBR (XNBR) is a terpolymer NBR with acidic organic monomer (typically 1 & 7%) carboxylic acid as a third monomer
• Reactions of ZnO and Carboxylic Acid result in a matrix with significantly increased mechanical properties, such as higher hardness, abrasion resistance and tear strength
• Although sacrifice in processing (mill and mould sticking) scorch, resilience and low temperature resistance, product retains the basic properties of NBR (oil & fuel resistance)
April 18, 2023Cancarb31
Applications
• Gasket and Seals - mainly NBR, high hardness seals ex/ Mud Pump – XNBR
• Hoses – NBR mainly in tubes, NBR/PVC bend mainly in cover
• Beltings• Rollers – NBR, XNBR for higher hardness rollers• Cable Jackets – NBR/PVC blends• Textile – spinning cots/aprons, NBR, NBR/PVC, XNBR• Industrial Footwear – NBR, NBR/XNBR blend, NBR/PVC
sponge soiling• Insulation – NBR/PVC sponge• Moulded/extruded components for various industries,
automotive• Fabric proofing – protective coatings, NBR• Milking inflation – NBR, resistance to fat
April 18, 2023Cancarb32
NBR/PVC Blend Example Using Thermax®
NBR/PVC Blend70/30 100 100Sulphur 1.5 1.5ZnO 5 5St. acid 1.5 1.5 N550 25 30Thermax® N990 45 60DOP 23 30 A.O. ODPA 1.5 1.5 P. Wax 3 3 TMTM .5 .5ML, 1+4@ 100°C 34 34MS, t5 @125°C 23’ 22’Cure Time @ 160°C 7.5’ 7.5’SH/TS/EB 68/143/450 70/131/415 Comp. set 22 h/70°C 27 27 Ageing in M15 test fuel (FAM 85 – Methanol 15), 48h at 23°CChange -18/-59/-60/+47.8v -19/-27/-51/+39v
High loading of Thermax® lowers the polymer content allowing for low swell in aggressive fuels, low compression set and good extrusion.
Gasohol Resistant Hoses Compound 1 Compound 2
April 18, 2023Cancarb33
April 18, 2023Cancarb34
Polychloroprene Structure
-CH2 H CH2 = C – CH = CH2
C=CCl
Cl CH2-
Chloroprene (liquid)
trans-1,4 polychloroprene (88-92 %) 2-chlorobutadiene
Similar to trans-1,4 isoprene but, the ‘CH3’ group has been replaced by ‘Cl’
Polychloroprene (CR)
April 18, 2023Cancarb35
• Polychloroprene is often called neoprene. Neoprene is, in
fact, the trade name of Dupont Dow Elastomers polychloroprene product line
• Polychloroprene has a structure similar to that of natural rubber except one of the methyl side groups is replaced by a chlorine atom and it is a trans-oriented molecule
• Polychloroprene can be sulfur modified or mercaptan modified to provide specific desired properties
Polychloroprene (CR)
April 18, 2023Cancarb36
Polychloroprene Rubber:
Crystallizes on stretching, allowing for:• High gum tensile strength; similar to Natural Rubber (NR)• Very good fatigue resistance
• When sulfur modified, will provide:• Excellent fatigue resistance• Highly resilient compounds• High tear resistance
• When mercaptan modified, will provide:• Better raw polymer stability• Good resistance to heat• Good resistance to compression set
Properties of Polychloroprene (CR)
April 18, 2023Cancarb37
Common applications of polychloroprene rubber are:
• Adhesives – polarity-bonding
• V-belts – tack and fire resistance
• Timing belts – tack and fire resistance
• Bellows – high flexibility
• Automotive seals
• Bridge bearing pads – good dynamic properties and ozone resistance
• Wire and cable – resistance to abrasion, oil, flame and weathering resistance
• Hose (especially covers) – good weathering resistance
Applications of Polychloroprene
April 18, 2023Cancarb38
• Thermax® will not degrade the inherently good mechanical properties of polychloroprene
• Thermax® lowers the compound viscosity which is essential for lower heat build-up during extrusion and good mold flow
• Thermax® will maintain the good compression set of the polychloroprene rubber
• Higher loading of Thermax® is possible resulting in a lower rubber content which decreases oil swell and reduces the compound cost
The Thermax® Advantage in Polychloroprene Rubber Compounds
Neoprene WRT 60SMR CV 60 40ZnO 5MgO 4Stearic acid 2Thermax® N990 40SRF 20Paraffinic Oil 2-3DPG 0.5TMTD 0.5Sulfur 1.06 PPD 1.5TMQ 1.5MC Wax 2Hardness 60
High loading of Thermax® reduces the polymer content (cost savings) which helps for low noise and gives a “clean” product & surface finish
Wiper Blade Compound
Polychloroprene Compound Example Using Thermax®
April 18, 2023Cancarb39
April 18, 2023Cancarb40
Fluoroelastomer Structure
- (CF2-CH2)X - (CF-CF2)Y - (CF2-CF2)Z
CF3
VF2
VinylidineFluoride
HFPHexafluoropropylene
TFETetrafluoroethylene
Fluoroelastomers (FKM)
April 18, 2023Cancarb41
• Fluorocarbon elastomers are a very popular choice for difficult sealing applications
• Fluoroelastomers are created by substituting fluorine for hydrogen on a carbon-based macromolecule
• Unlike hydrocarbon rubbers, which are non-polar, the presence of fluorine creates polar molecules
• Fluoroelastomers are expensive and difficult to process due to their relatively high molecular weight
Fluoroelastomers - FKM
April 18, 2023Cancarb42
Fluoroelastomers:
• Can be compounded to provide high heat resistance and thermal
stability
• Have excellent oil & gasoline resistance
• Have excellent hydrocarbon-based solvent resistance
• Have very good impermeability
• Are flame resistant
• Are resistant to weathering
• Have excellent compression set resistance
• Are expensive
• Tend to have high Mooney viscosities which accelerate heat build-up when mixing
Properties of Fluoroelastomers
April 18, 2023Cancarb43
Common applications of Fluoroelastomers are:
• Automotive – Valve Stem Seals, Shaft Seals, ‘O’ Rings
• Aerospace – ‘O’ Rings for Hydraulic, Lubricating and Fuel Systems
• Oil Field – Packers & Blow-out Preventers
• Industrial – Expansion Joints in Mines, Gaskets, Valve & Pump Linings
• Hoses – Fuel Lines, Turbo Chargers, Bio-diesel
Applications of Fluoroelastomers
April 18, 2023Cancarb44
• High loadings of Thermax® will not reduce the excellent compression set and low swell inherent to FKM• Excellent for ‘O’ ring and seal applications
• The higher loading ability of Thermax® improves the impermeability of the compound• The best choice for fuel line hose veneer
• The specific gravity of Thermax® is similar to that of FKM, so higher loading of Thermax allows for the same volume of compound to be produced while using less of the expensive FKM elastomer, without sacrificing the desired compound properties.• Overall compound cost reduction
The Thermax® Advantage in FKM Compound Applications
FKM Compound Example Using Thermax®
Dyneon FC 2176 100 100
Maglite D 3 3
Calcium Hydroxide 6 6
SRF 20 -
Thermax® N990 - 30
Press cure 10‘@177°C+Post cure 24hrs@260°C
Tensile Strength (psi) 2120 1970
Elongation at Break (%) 220 290
Shore A Hardness 80 76
Air Ageing 70 hrs/276°C
Tensile Strength (psi) 1695 1405
Elongation at Break (%) 330 295
Shore A Hardness 81 77
Compression set (%) 50 28
- Method B (0.139” O rings) 70 hrs/200°C
FKM O-ring Compound 1 Compound 2
Thermax® enables higher loading while maintaining adequate original mechanical properties with excellent ageing properties, compression set resistance and low swell
April 18, 2023Cancarb45
Ethylene Propylene Diene Rubber (EPDM)
April 18, 2023Cancarb46
Structure
CH3|
Ethylene Propylene
CH2 = CH2 + CH = CH2 + A Diene Monomer
Diene Monomers Used in EPDM
• DCPD - dicyclopentadiene• ENB - ethylidene nobornene• VNB - vinyl norbornene
Typically, ethylene comprises 45% to 80% of the polymer with the diene making up 2.5% to 12%.
Ethylene Propylene Diene Rubber (EPDM)
Increasing the ethylene content in EPDM provides:• Improved cold green strength• Excellent theroplasticity which improves extrusion and mold
flow characteristics• Increased filler and oil loading ability• Higher heat resistance• Good cured tensile strength properties
But:• It is responsible for less building tack• It is more difficult to mix• Mill processing at low temperatures is difficult• Compression set and recovery in cold temperatures is poor• Flex resistance and elastic recovery are reduced
April 18, 2023Cancarb47
EPDM – Molecular Weight Distribution
EPDM Polymer can be produced with a range of Molecular Weight Distribution (MWD).
High molecular weight distribution EPDM provides for:• Excellent hot green strength, important for shaping and
continuous vulcanization• High collapse resistance critical for hollow extruded sections• Less porosity in extrudates• Excellent physical properties• Low compression set• Improved resilience• Facilitates oil and filler extension which improves the
difficult processing characteristics common to high MWD polymers
• Higher loading of filler for lower cost compounds
April 18, 2023Cancarb48
Ethylene Propylene Diene Rubber (EPDM)
Increasing the diene content of the polymer provides:
• Shorter cure times• Higher resilience• Higher modulus• Lower compression set• Cure compatibility with unsaturated rubbers
April 18, 2023Cancarb49
Properties of EPDM
EPDM based rubber offers:• Excellent weather and ozone resistance• Excellent high & low temperature resistance• Excellent water and chemical resistance• Excellent dielectric properties
But,• Poor resistance to oils and hydrocarbon solvents• Poor adhesion
April 18, 2023Cancarb50
Applications of EPDM Rubber
Automotive industry• Extruded Profiles – solid and sponge• Hoses – Radiator and Heater• Seals and grommets
April 18, 2023Cancarb51
Appliance Industry• Washing machine parts – gaskets, elbows and hoses
Construction Industry• Glass profiles• Flooring• Membranes• Roofing
Electrical Industry• Low and Medium voltage cabling – cable jackets
Chemical Industry• Hoses• Seals
EPDM Compound Example Using Thermax®
Keltan 512 100ZnO 5St. Acid 1Benzoic acid 1Thermaxx® N990 100Winnofil S (Coated pptd CaCO3) 35Sunpar 150 60Vaselin 10 Rotor/Roll ReleaseTMTD 2MBTS 2Sulphur 2Benzene Sulphohydrazide 3Benzene 1,3 Disulphohydrazide 3
ML 1+4@100°C 19Cure time 15’@160Specific Gravity 0.52
Higher Loading reduces costs. Low compound Mooney helps efficient blowing, gives uniform cell structure
Automotive Moulded Sponge
April 18, 2023Cancarb52
Metallocene EPDM Technology
• The introduction of EPDM in the world market produced by Metallocene Catalyst Technology has increased the scope for the usage of Thermal Black in these rubbers considerably
• EPDM produced by Metallocene Catalyst Technology has very high molecular weight compared to traditional EPDM Rubbers produced from solution and suspension polymerization technology
• EPMD Rubbers with Metallocene Technology are very difficult to process when compounded with furnace blacks alone. Blending Thermax in blend with the furnace black lowers the compound viscosity allowing for easy processing without a negative affect on mechanical properties
April 18, 2023Cancarb53
April 18, 2023Cancarb54
• High loadings of Thermax® can reduce the compound cost without sacrificing compression set and dynamic properties
• Thermax reduces the compound viscosity which improves processing, blowing and molding properties
• The very low grit level of Thermax maintains excellent surface finish and ensures a uniform cell structure in sponge applications.
• The excellent dispersion of Thermax results in consistent heat transfer throughout the extrusion and uniform cooling
The Thermax® Advantage in EPDM Compound Applications
Chlorosulfonated Polyethylene Rubbers (CSM)
Polyethylene, a low cost plastic, is chemically modified to a cross-linkable rubber, retaining some of the important properties of polyethylene such as chemical resistance and electrical properties
This polymer is almost exclusively produced by DuPont Performance Elastomers under the trade name Hypalon®. On May 7th, 2009, DuPont announced that it will cease production of Hypalon® and completely exit the CSM business
April 18, 2023Cancarb55
Structure
- (CH2-CH2)x – (CH2-CH)y – (CH2-CH)z -|
Cl|
SO2
|Cl
Properties and Grades of CSM
Properties
• Excellent resistance to weather, ozone, sunlight, oxidation, alkalies and acids
• Good resistance to oil and gasoline• Good flame resistance, abrasion resistance• It is close to polychloroprene in most properties but superior
in resistance to acids, alkalies, solvents, Ozone and oxidation with better color stability
Grades
• Depending on the Cl content, range 24% to 43%, ‘S’ content around 1%, varying Mooney
• Increasing Cl content give oil and flame resistance
April 18, 2023Cancarb56
Applications of CSM Rubbers
April 18, 2023Cancarb57
Grade Cl content (%)Mooney Viscosity ML 1=4
@ 100°CHypalon 40/40S 35 56/45
Hoses
W & C
Rolls
Hypalon 45 24 37
W & C
Low Temp. Applications
Hypalon 48/48S 43 78/62
Excellent oil resistance
low permeability to Freon
Air Conditioner Hoses
Butyl Rubber (IIR)
April 18, 2023Cancarb58
CH3
|
|CH3
CH3
|
Isobutylene Isoprene
+
Structure
Butyl Rubber is a copolymer of isobutylene and a small amount ofIsoprene, typically around 2%
Chlorobutyl (CIIR) and bromobutyl (BIIR) rubbers are produced in a similar manner, but with and additional halogenation stage required
Properties of Butyl Rubbers
• Presence of “bulky” isobutylene groups causes slow movement of the polymer chain which gives butyl rubber excellent impermeability to air, oxygen and water
• -CH3 groups along the chains interfere with each other, reduce the speed with which the molecules
• Low unsaturation makes Butyl more resistant to heat ageing and to attacks by acids, alkalis, oxidizing agents, ozone, water and steam, than general purpose polymers such as SBR, BR and NR
• Butyl rubber is very similar in structure to polyisobutylene and has a similar glass transition temperature (Tg) of -70°C
• Butyl has low resilience and very poor resistance to compression set, oil and hydrocarbon based solvents
• Low unsaturation slows the compound cure rate and reduces Butyl’s compatibility with the more unsaturated rubbers such as NR, SBR and BR. Even small amount mixed in with these rubbers gives a disastrous effect on compound properties
April 18, 2023Cancarb59
• Virtually all halogenation takes place at the isoprene portions of the IIR Chains which represent approximately 2.0 mole% of the IIR Co-Polymer
• Commercial chlorobutyls contain 1.1 to 1.3% weight of chlorine and bromobutyls contain 1.9 to 2.1% weight of Bromine
• Stearic hindrance of the double bond favors substitution rather than addition, so most of the unsaturation is retained, although it is now largely isomerised
Halobutyl Rubber
April 18, 2023Cancarb60
-CH2-C=CH-CH2-
CH3
| (-CH2-C-CH-CH2-)
CH3
|
|X
+ (X )-
+ (-CH2-C-CH-CH2-)
CH2
||
|X
+ (HX)X=Cl or Br
Add X2 Minus H+
Isoprene Halobutyl
Butyl versus Halobutyl Rubber
Butyl rubber Chlorobutyl Bromobutyl
Cure reactivity
Compatibility with other unsaturated rubbers
Tack
Cure adhesion with other rubbers
• Increased cure compatibility reduces the need for stringent precautions against contamination with other unsaturated rubbers
• Flexibility and resistance to dry heat are almost identical for both Chloro and Bromobutyl rubber
April 18, 2023Cancarb61
Permeability of Halobutyl
Typical Tire Inner Liner Compound
Permeablility rates at 65°C Air Moisture100% NR 8.3 13.3100% SBR 6.8 11.0HIIR/NR (60:40) 3.1 3.0100% HIIR 1.0 1.0
The excellent permeability of Halobutyl rubber makes it a very popular choice for tire inner liners
April 18, 2023Cancarb62
Applications of Butyl and Halobutyl Rubber
• Inner tubes for tires (IIR, HIIR)
• Heat resistant conveyor belts (HIIR)
• Tire Inner liners (HIIR)
• Tank linings (HIIR)
• Side Walls (HIIR)
• Dampers/bridge bearing pads (IIR/HIIR)
• Tire curing bladders (HIIR)
• Adhesives/sealants (cross-linked IIR, HIIR)
• Steam/Automotive Hoses (HIIR)
• Pharmaceutical closures (HIIR)
April 18, 2023Cancarb63
April 18, 2023Cancarb64
• High loadings of Thermax® can reduce the overall compound cost without a significant loss in compound properties
• The higher loading ability of Thermax® improves the impermeability of the compound by replacing polymer with impermeable filler
• Thermax can raise the viscosity of the compound making it easier and less expensive to process
• Improved adhesion can be achieved with Thermax® which is very important for inner liner and other rubber to rubber bonding applications.
The Thermax® Advantage in IIR & HIIR Compound Applications
April 18, 2023Cancarb65
Questions & Answers