6.rubber compounding technology-final.ppt
TRANSCRIPT
RUBBER COMPOUNDING RUBBER COMPOUNDING TECHNOLOGYTECHNOLOGY
SUDHA.PSUDHA.P DEPUTY DIRECTOR(RIDT) DEPUTY DIRECTOR(RIDT)
RUBBER TRAINING INSTITUTERUBBER TRAINING INSTITUTE DEPARTMENT OF TRAININGDEPARTMENT OF TRAINING
RUBBER BOARDRUBBER BOARDKOTTAYAM-686 009KOTTAYAM-686 009
[email protected]@rubberboard.org.inMob: 94964 13731Mob: 94964 13731
RUBBER RUBBER COMPOUNDINGCOMPOUNDING
COMPOUNDCOMPOUNDIt is a homogenous mixture of ingredients used in a It is a homogenous mixture of ingredients used in a particular product manufacture such that the properties particular product manufacture such that the properties of most of the ingredients are unchanged in the final of most of the ingredients are unchanged in the final product whereby providing a defined set of product whereby providing a defined set of mechanical properties.mechanical properties.
COMPOUNDINGCOMPOUNDINGIt is the science of selecting and combining elastomers It is the science of selecting and combining elastomers and additives to obtain physical and chemical and additives to obtain physical and chemical properties for a finished product.properties for a finished product.
RUBBER COMPOUNDINGRUBBER COMPOUNDING
OBJECTIVEOBJECTIVE
1.1. To secure To secure certain properties in the finished product to certain properties in the finished product to satisfy the service requirements.satisfy the service requirements.
2.2. To attain processing characteristics necessary for efficient To attain processing characteristics necessary for efficient utilization of available equipment.utilization of available equipment.
3.3. To achieve desirable properties and processability at the To achieve desirable properties and processability at the lowest cost.lowest cost.
The most important factor in compounding is to secure an The most important factor in compounding is to secure an acceptable balance among demands arising from the above acceptable balance among demands arising from the above three criteria.three criteria.
MAJOR OBJECTIVES OF COMPOUND MAJOR OBJECTIVES OF COMPOUND DEVELOPMENTDEVELOPMENT
PROCESS REQUIREMENTPROCESS REQUIREMENT Proper mixing (Incorporation, dispersion, distribution and Proper mixing (Incorporation, dispersion, distribution and
plasticization)plasticization) Viscosity/process safety (ML1+4, MS)Viscosity/process safety (ML1+4, MS) Stickiness and tackinessStickiness and tackiness Shaping (Calendering, Extrusion, Assembling and Moulding)Shaping (Calendering, Extrusion, Assembling and Moulding)
COMPOUND PROPERTY REQUIREMENTCOMPOUND PROPERTY REQUIREMENT Hardness Hardness Stress-Strain properties (TS, EB, M-100, M-300, tear)Stress-Strain properties (TS, EB, M-100, M-300, tear) Abrasion resistanceAbrasion resistance Hysteresis & set propertiesHysteresis & set properties Resistance to cut growth, fatigue, flex crackingResistance to cut growth, fatigue, flex cracking
MAJOR OBJECTIVES OF COMPOUND MAJOR OBJECTIVES OF COMPOUND DEVELOPMENTDEVELOPMENT
RESISTANCE TO DEGRADATIONRESISTANCE TO DEGRADATION
Heat, Oxygen, OzoneHeat, Oxygen, Ozone FlameFlame LiquidsLiquids LightLight
MISCELLANEOUS PROPERTY REQUIREMENTSMISCELLANEOUS PROPERTY REQUIREMENTS Low temperature flexibilityLow temperature flexibility Electrical propertiesElectrical properties PermeabilityPermeability Contact with food stuff and drugsContact with food stuff and drugs Bonding to metal & textilesBonding to metal & textiles SwellingSwelling Other specific requirementsOther specific requirements
CLASSIFICATION OF COMPOUNDING CLASSIFICATION OF COMPOUNDING INGREDIENTSINGREDIENTS
1.1. ElastomersElastomers2.2. Vulcanizing Agents (curatives)Vulcanizing Agents (curatives)3.3. AcceleratorsAccelerators4.4. Activators and RetardersActivators and Retarders5.5. Antidegradants (Anti-oxidants, Antiozonants, Protective Antidegradants (Anti-oxidants, Antiozonants, Protective
waxes )waxes )6.6. Processing aids (Peptisers, Lubricants, Release Agents)Processing aids (Peptisers, Lubricants, Release Agents)7.7. Fillers (carbon black, non-black materials)Fillers (carbon black, non-black materials)8.8. Plasticizers, Softeners and TackifiersPlasticizers, Softeners and Tackifiers9.9. Colour pigmentsColour pigments10.10. Special Purpose Materials (Blowing Agents, Deodorants, Special Purpose Materials (Blowing Agents, Deodorants,
etc.)etc.)
COMPOUND DESIGNCOMPOUND DESIGN
DESIGN REQUIREMENTSDESIGN REQUIREMENTS SERVICE REQUIREMENTS/VULCANISATE PROPERTIESSERVICE REQUIREMENTS/VULCANISATE PROPERTIES PROCESSABILITYPROCESSABILITY ECONOMICSECONOMICS
DESIGN BASED ON DESIGN BASED ON CUSTOMER SPECIFICATION/REQUIREMENTSCUSTOMER SPECIFICATION/REQUIREMENTS COMPETITOR'S SAMPLECOMPETITOR'S SAMPLE DEVELOP A NEW PRODUCT DEVELOP A NEW PRODUCT
POLYMER SELECTION POLYMER SELECTION CRITERIACRITERIA CostCost Ease of mixingEase of mixing Strength requirementsStrength requirements Modulus or stiffness requirementModulus or stiffness requirement Abrasion resistance requirementAbrasion resistance requirement Elongation requirementElongation requirement Oil resistance requirementOil resistance requirement Low temperature requirementLow temperature requirement Fatigue requirementFatigue requirement TackTack Set of stress relaxationSet of stress relaxation Service temperatureService temperature Dynamic properties (hysteresis, damping resistance)Dynamic properties (hysteresis, damping resistance) FlammabilityFlammability Chemical resistanceChemical resistance
POLYMER SELECTION POLYMER SELECTION
SHOULD HAVE THOROUGH KNOWLEDGE ABOUT POLYMER SHOULD HAVE THOROUGH KNOWLEDGE ABOUT POLYMER PROPERTIESPROPERTIES
REFER STANDARD SELECTION CHARTS/COMPARATIVE REFER STANDARD SELECTION CHARTS/COMPARATIVE CHARTSCHARTS
BLENDS OF POLYMERSBLENDS OF POLYMERS PROCESSABILITY FACTOR-suitability for the processes and methods PROCESSABILITY FACTOR-suitability for the processes and methods
adoptedadopted COST FACTORCOST FACTOR AVAILABILITY OF DATA ON POLYMER GRADES, PROPERTIES, AVAILABILITY OF DATA ON POLYMER GRADES, PROPERTIES,
START UP FORMULATIONS ETC.START UP FORMULATIONS ETC.
VULCANIZING AGENTSVULCANIZING AGENTS
TYPETYPE COMMON USECOMMON USE
Sulphur or Sulphur bearing Sulphur or Sulphur bearing materialsmaterials
Natural Rubber, Isoprene, SBR, Natural Rubber, Isoprene, SBR, Butyl, Poly Butadiene, EPDM, Butyl, Poly Butadiene, EPDM, NitrileNitrile
Organic PeroxidesOrganic Peroxides Urethane, Silicone, Chlorinated Urethane, Silicone, Chlorinated Polyethylene, PVC/NitrilePolyethylene, PVC/Nitrile
Metallic OxideMetallic Oxide Polychloroprene, Chlorosulphonated Polychloroprene, Chlorosulphonated Polyethylene, PolysulphidePolyethylene, Polysulphide
Organic AminesOrganic Amines Acrylic, Fluorocarbon, Acrylic, Fluorocarbon, EpichlorohydrinEpichlorohydrin
Phenolic ResinsPhenolic Resins ButylButyl
CURING SYSTEMCURING SYSTEM
Selection of curing system is based on:Selection of curing system is based on: Base polymerBase polymer Processing conditionsProcessing conditions Curing conditionsCuring conditions Service requirementService requirement
Base polymerBase polymer Saturated rubber – peroxide e.g. EPR with DCPSaturated rubber – peroxide e.g. EPR with DCP Unsaturated rubber-peroxide, sulphur/accelerator & resins, e.g. EPDM Unsaturated rubber-peroxide, sulphur/accelerator & resins, e.g. EPDM
with DCP, NR with sulphur accelerator, IIR with Resinwith DCP, NR with sulphur accelerator, IIR with Resin Special Polymers – Metal oxide, Dioxime, Resin e.g. CR with ZnO/MgOSpecial Polymers – Metal oxide, Dioxime, Resin e.g. CR with ZnO/MgO
ACCELERATORSACCELERATORS
An accelerator is usually a complex organic chemical which takes part in the An accelerator is usually a complex organic chemical which takes part in the vulcanization, thereby reducing the vulcanization time considerably- Organic vulcanization, thereby reducing the vulcanization time considerably- Organic amines & its derivatives . It also improves the properties. Its action may be:amines & its derivatives . It also improves the properties. Its action may be:
slow- eg. Guanidinesslow- eg. Guanidines, , Diphenyl guanidine (DPG)Diphenyl guanidine (DPG) Di ortho tolyl guanidine(DOTGDi ortho tolyl guanidine(DOTG) )
mediummedium- eg. Thiazoles, - eg. Thiazoles, Mercapto benzo thiazole (MBT)Mercapto benzo thiazole (MBT) Di benzthiazyl di sulphide) (MBTS) Di benzthiazyl di sulphide) (MBTS)
fast ( ultra)-fast ( ultra)- eg. Thiurams, eg. Thiurams, Tetramethyl thiuram monosulphide (TMTM)Tetramethyl thiuram monosulphide (TMTM) Tetramethyl thiuram di sulphide (TMT)Tetramethyl thiuram di sulphide (TMT)
Dithiocarbamates, Dithiocarbamates, Zinc diethyl dithiocarbamate (ZDC)Zinc diethyl dithiocarbamate (ZDC) Zinc dibutyl dithiocarbomate(ZDBC)Zinc dibutyl dithiocarbomate(ZDBC)
Delayed-action fast- eg. SulfenamidesDelayed-action fast- eg. SulfenamidesCyclohexyl benzthiazyl sulfenamide (CBS)Cyclohexyl benzthiazyl sulfenamide (CBS)Dicyclohexyl benzthiazyl sulfenamide (DCBS)Dicyclohexyl benzthiazyl sulfenamide (DCBS)Morpholino thio benzthiazylsulfenamide (MOR)Morpholino thio benzthiazylsulfenamide (MOR)Tertiary butyl benzthiazyl sulfenamide (TBBS)Tertiary butyl benzthiazyl sulfenamide (TBBS)
CURING SYSTEM (Contd..)CURING SYSTEM (Contd..)
Accelerator ActivatorAccelerator Activator ZnO and Stearic acid for sulphur cure systemZnO and Stearic acid for sulphur cure system TAC for peroxide cure systemTAC for peroxide cure system
Processing conditionProcessing condition Type of processing equipment usedType of processing equipment used Temperature build up during processingTemperature build up during processing Extent of rework usageExtent of rework usage Rheological property requirementRheological property requirement
Curing conditionsCuring conditions Type of the productType of the product Method of curing employedMethod of curing employed Temperature of curingTemperature of curing Flow requirement during curingFlow requirement during curing
CURING SYSTEM (Contd..)CURING SYSTEM (Contd..)
Service RequirementsService Requirements Service temperatureService temperature Duration of exposure Duration of exposure Mechanical property requirement.Mechanical property requirement. Dynamic property requirementDynamic property requirement Ageing behaviour and permanent set requirements.Ageing behaviour and permanent set requirements. Special property requirement.Special property requirement.
FILLERSFILLERS
• Fillers are materials used to extent the range of Fillers are materials used to extent the range of physical properties, to reduce compound cost, modify physical properties, to reduce compound cost, modify the processing properties and to influence the the processing properties and to influence the chemical resistance of the compound.chemical resistance of the compound.
The effect of a filler on rubber depends on-The effect of a filler on rubber depends on-• structurestructure• particle sizeparticle size• surface areasurface area• geometrical characteristicsgeometrical characteristics
FILLERSFILLERS
Reinforcing TypeReinforcing Type Carbon Black (listed in Carbon Black (listed in order of increasing order of increasing particle size)particle size)
N220 (ISAF)N220 (ISAF)
N330(HAF)N330(HAF)
N550 (FEF)N550 (FEF)
N762 (SRF-LM)N762 (SRF-LM)
N990 (MT)N990 (MT)
Non-blackNon-black SilicaSilica
Zinc OxideZinc Oxide
Magnesium CarbonateMagnesium Carbonate
Aluminium SilicateAluminium Silicate
Sodium AluminosilicateSodium Aluminosilicate
Magnesium SilicateMagnesium Silicate
Extending TypeExtending Type Calcium CarbonateCalcium Carbonate
Barium SulfateBarium Sulfate
Aluminium TrihydrateAluminium Trihydrate
Talc and SoapstoneTalc and Soapstone
• reinforcing carbon blacks reinforcing carbon blacks • non- reinforcing carbon blacksnon- reinforcing carbon blacks• reinforcing non- blackreinforcing non- black• semi reinforcing non- blacksemi reinforcing non- black• non- reinforcing non- blacknon- reinforcing non- black
• Reinforcing carbon blacksReinforcing carbon blacks Furnace black Furnace black SAF – Super Abrasion FurnaceSAF – Super Abrasion Furnace ISAF – Intermediate Super Abrasion FurnaceISAF – Intermediate Super Abrasion Furnace CFCF - Conductive Furnace- Conductive Furnace SCFSCF - Super Conductive Furnace- Super Conductive Furnace
HAFHAF - - High Abrasion Furnace (Low High Abrasion Furnace (Low structure and high structure) structure and high structure)
FFFF -- Fine FurnaceFine Furnace
FEFFEF -- Fine Extrusion FurnaceFine Extrusion Furnace
GPFGPF -- General Purpose FurnaceGeneral Purpose Furnace
SRFSRF -- Semi Reinforcing FurnaceSemi Reinforcing Furnace
Thermal BlackThermal Black
MT - Medium ThermalMT - Medium Thermal• Channel black Channel black • EPCEPC Easy Processing ChannelEasy Processing Channel• Reinforcing Non- blackReinforcing Non- black
Precipitated silica and fumed silicaPrecipitated silica and fumed silica• Semi Reinforcing Non-blackSemi Reinforcing Non-black
aluminium and calcium silicatesaluminium and calcium silicates
high styrene resins high styrene resins
phenolic resinsphenolic resins
FillersFillers
Selection is based on Selection is based on • ReinforcementReinforcement• CostCost• Processing requirementProcessing requirement• Colour requirementColour requirement• Service requirementService requirement• Any other special requirementAny other special requirement
Compound Designing – Hardness
Polymer HardnessPolymer Hardnessphr required phr required for 1 unit for 1 unit increase in increase in HardnessHardness
NRNR SBRSBR CRCR NBRNBR
37-4037-40 39-4139-41 41-4341-43 42-4442-44
22 1.61.6 1.51.5 Ppt. SilicaPpt. Silica
33 3.33.3 2.22.2 Calcium silicateCalcium silicate
55 4.14.1 4.54.5 Hard clayHard clay
7.97.9 5.65.6 5.05.0 Soft claySoft clay
6.66.6 8.48.4 5.05.0 WhitingWhiting
Compound Designing – HardnessCompound Designing – Hardness
Contd.Contd.
NRNR SBRSBR IIRIIR CRCR PBR PBR NBRNBR EPDMEPDM BlackBlack ASTM ASTM DsgnDsgn
DBPDBP
1.51.5 1.81.8 1.31.3 1.21.2 2.22.2 1.71.7 2.42.4 SAFSAF N110N110 113113
1.71.7 2.02.0 1.51.5 1.31.3 2.52.5 1.91.9 2.72.7 ISAFISAF N220N220 114114
1.91.9 2.32.3 1.71.7 1.51.5 2.82.8 2.12.1 3.03.0 HAFHAF N330N330 102102
2.32.3 2.82.8 2.12.1 1.81.8 3.43.4 2.62.6 3.73.7 FEFFEF N550N550 119119
2.52.5 3.13.1 2.32.3 2.02.0 3.83.8 2.92.9 4.14.1 GPFGPF N660N660 9090
2.82.8 3.43.4 2.52.5 2.22.2 4.24.2 3.23.2 4.54.5 SRFSRF N774N774 7070
2.12.1 2.62.6 1.91.9 1.71.7 3.23.2 2.42.4 3.43.4 HAF-HAF-LSLS
N326N326 7272
SOFTENERSSOFTENERS
Processing aidsProcessing aidsA softener is an ingredient that :A softener is an ingredient that :
1.1. speeds up the rate of polymer breakdown speeds up the rate of polymer breakdown 2.2. helps to disperse the other compounding helps to disperse the other compounding ingredientsingredients3.3. helps to reduce nerve within the compoundhelps to reduce nerve within the compound44 can impart building tackcan impart building tack5.5. improves the processing properties and improves the processing properties and modify the final modify the final compound propertiescompound properties6.6. adjusts the compound cost and reduce power adjusts the compound cost and reduce power
consumption during processing consumption during processing
Mineral petroleum oilsMineral petroleum oils They are available from petroleum industry.They are available from petroleum industry.
paraffinicparaffinicnaphthenicnaphthenicaromaticaromatic
Plasticizers Plasticizers They are of the synthetic type , used where mineral They are of the synthetic type , used where mineral
oils are not compatible with the rubberoils are not compatible with the rubberdibutyl phthalate -DBP dibutyl phthalate -DBP di isobutyl phthalate-DIBdi isobutyl phthalate-DIBdi octyl phthalate - DOPdi octyl phthalate - DOP
**FacticesFactices They are vulcanized vegetable oils used as plasticizers to get They are vulcanized vegetable oils used as plasticizers to get smooth compound in extrusion (brown) & to reduce abrasion smooth compound in extrusion (brown) & to reduce abrasion resistance in products like erasers (white) resistance in products like erasers (white)
PROCESSING AIDSPROCESSING AIDS
COMPOSITIONCOMPOSITION EXAMPLEEXAMPLE FUNCTIONFUNCTIONActivated Dithio-Activated Dithio-bisbenzaldihidebisbenzaldihide
Pepton 44Pepton 44 Peptizer for NRPeptizer for NR
Xylyl MercaptansXylyl Mercaptans RPA-3RPA-3 Peptizer for NR,IR,SBR and Peptizer for NR,IR,SBR and NBR. NBR.
Low-molecular-weight Low-molecular-weight polyethylenepolyethylene
A-C Polyethylene A-C Polyethylene 617A617A
Release agent, LubricantRelease agent, Lubricant
Calcium OxideCalcium Oxide Desical PDesical P DesiccantDesiccant
Aliphatic-naphthenic-Aliphatic-naphthenic-aromatic resinsaromatic resins
Strucktol 60NSStrucktol 60NS Homogenizing agent for all Homogenizing agent for all elastomers.elastomers.
Paraffin waxParaffin wax Release agent, lubricantRelease agent, lubricant
Polyethylene glycolPolyethylene glycol Carbowax Carbowax PEG3350PEG3350
Activator for silica, lubricantActivator for silica, lubricant
Petroleum hydrocarbonPetroleum hydrocarbon PetrolatumPetrolatum Release agent, lubricantRelease agent, lubricant
PROCESSING AIDSPROCESSING AIDS
Selection is based onSelection is based on
Nature of polymerNature of polymer Solubility parameterSolubility parameter Viscosity requirementViscosity requirement Filler dispersionFiller dispersion Processing requirementProcessing requirement Any other special requirementAny other special requirement
ANTI-DEGRADANTSANTI-DEGRADANTS- - They are agents added to rubber to improve They are agents added to rubber to improve ageing properties, resistance to oxygen, ozone, alkali, acid, chemicals etcageing properties, resistance to oxygen, ozone, alkali, acid, chemicals etc
TYPETYPE EXAMPLEEXAMPLE STAININGSTAINING
Hindered PhenolHindered Phenol 2,6 Di-t butyl p-cresol2,6 Di-t butyl p-cresol None to slightNone to slight
Hindered Bis-phenolsHindered Bis-phenols Anti-oxidant 2246Anti-oxidant 2246 None to slightNone to slight
Hindered ThiobisphenolsHindered Thiobisphenols Santowhite CrystalsSantowhite Crystals SlightSlight
HydroquinonesHydroquinones 2,5 di(tert-amyl) hydroquinone2,5 di(tert-amyl) hydroquinone None to slightNone to slight
PhosphitesPhosphites Tri(mixed mono and di-nonyl-Tri(mixed mono and di-nonyl-phenyl) phosphitephenyl) phosphite
None to slightNone to slight
DiphenylaminesDiphenylamines Octylated diphenylamineOctylated diphenylamine Slight to moderateSlight to moderate
NaphthylaminesNaphthylamines Phenyl-alpha-naphthylaminePhenyl-alpha-naphthylamine ModerateModerate
QuinolinesQuinolines Polymerized 2,2,4, tri-methyl Polymerized 2,2,4, tri-methyl 1,2-dihydroquinoline1,2-dihydroquinoline
Slight to moderateSlight to moderate
Carbonyl-amines Carbonyl-amines condensation productcondensation product
Reaction product of Reaction product of diphenylamine and acetonediphenylamine and acetone
ConsiderableConsiderable
Para-phenylene diaminesPara-phenylene diamines Mixed Diaryl-p-phenylene Mixed Diaryl-p-phenylene diaminesdiamines
Considerable to severeConsiderable to severe
ANTI-DEGRADANTSANTI-DEGRADANTS
Selection is based onSelection is based on
Type of protection desiredType of protection desired Environment in which the product is exposed.Environment in which the product is exposed. Chemical activityChemical activity Persistence (volatility and extractability)Persistence (volatility and extractability) Nature of end useNature of end use Discolouration and stainingDiscolouration and staining ToxicologyToxicology CostCost
OTHER MATERIALSOTHER MATERIALS
PeptizersPeptizers : They speed up the rate of polymer break down and : They speed up the rate of polymer break down and also control the speed of breakdown, decreasing nerve within the also control the speed of breakdown, decreasing nerve within the compound and shrinkage during subsequent processing.compound and shrinkage during subsequent processing.
penta chloro thiophenolpenta chloro thiophenol Renacit VIIRenacit VII
RetardersRetarders : They help to increase the scorch time (premature : They help to increase the scorch time (premature vulcanization) but do not interfere with the vulcanizationvulcanization) but do not interfere with the vulcanization
cyclohexyl thiophthalimide (CTP)cyclohexyl thiophthalimide (CTP) Santogard PVISantogard PVI
StiffenersStiffeners : Stiffeners are used to improve the plasticity of the : Stiffeners are used to improve the plasticity of the compound in very small quantities.compound in very small quantities.
dihydrazine sulfatedihydrazine sulfate
Flame retardantsFlame retardants
Chemicals which can improve the flame retardency Chemicals which can improve the flame retardency of the compoundof the compound
highly chlorinated paraffins and waxes, antimony oxide, highly chlorinated paraffins and waxes, antimony oxide, aluminium oxide and selenium aluminium oxide and selenium
Colors and pigmentsColors and pigments They provide esthetic look and appearance for the product They provide esthetic look and appearance for the product
[organic and inorganic] [organic and inorganic] Tackifying agentsTackifying agents
They are useful in providing tackiness to the compound.They are useful in providing tackiness to the compound.
wood rosin, coumarone resins, pine tar.wood rosin, coumarone resins, pine tar.
Blowing agentsBlowing agents They are materials which provide either open or They are materials which provide either open or
closed cell structure by producing CO2 or nitrous closed cell structure by producing CO2 or nitrous gases during vulcanization gases during vulcanization
dinitroso pentamethylene tetramene (DNPT)dinitroso pentamethylene tetramene (DNPT) azocarbonamide (ADC)azocarbonamide (ADC) baking soda (sod.bicarbonate)baking soda (sod.bicarbonate)
Bonding agentsBonding agents They facilitate adhesion between rubbers, fibers, fabrics, They facilitate adhesion between rubbers, fibers, fabrics,
metalsmetals chemlok, resorcinol – formaldehyde- latex for dipping of chemlok, resorcinol – formaldehyde- latex for dipping of
nylon cords in tyre manufacturenylon cords in tyre manufacture ReordantsReordants They are basically perfumes added to mask odors of rubber They are basically perfumes added to mask odors of rubber
during processing and service life of rubber.during processing and service life of rubber. Bactericides / fungicidesBactericides / fungicides to resist microbial agents to resist microbial agents
STEPS OF COMPOUND DEVELOPMENTSTEPS OF COMPOUND DEVELOPMENTModification of existing compound with respect toModification of existing compound with respect to
Cost/priceCost/price ProcessingProcessing PerformancePerformance
New compound developmentNew compound development
Set specific objectives (properties, processing, price etc)Set specific objectives (properties, processing, price etc) Select best polymerSelect best polymer Study test data of existing compoundsStudy test data of existing compounds Survey compound formulations.Survey compound formulations. Choose starting formulation.Choose starting formulation. Develop compound in the laboratory to meet objectives.Develop compound in the laboratory to meet objectives. Estimate cost of the compound.Estimate cost of the compound. Evaluate processability in factoryEvaluate processability in factory Use compound to make a product sample.Use compound to make a product sample. Test product sample against performance specification.Test product sample against performance specification.
The mixThe mix RubberRubber 100100 Vulcanizing agentVulcanizing agent 0.3 - 3.50.3 - 3.5 Accelerator/sAccelerator/s 0.5 – 1.50.5 – 1.5 ActivatorActivator 2.5 – 5.02.5 – 5.0 Antidegradents Antidegradents 1 - 21 - 2 Fillers Fillers As requiredAs required
SoftnerSoftner 5 - 105 - 10 Other materials when necessaryOther materials when necessary As requiredAs required
STAGES OF PRODUCT DEVELOPMENTSTAGES OF PRODUCT DEVELOPMENT : :Compound Design,
Lab Evaluation,
Shop floor processing trials (mixing, moulding,extrusion, calendaring, fabrication of product, curing, etc ),
Analysis of feedback ,
Compound Modification (if reqd.),
Testing of processing properties and of finished product,
Field trials,
Validation of manufacturing process.
MIXINGMIXING
Compound properties & batch to batch consistency depends Compound properties & batch to batch consistency depends on :on :
Compounding formulation design,Compounding formulation design, Raw materials Quality, Raw materials Quality, Effects of Further Processing,Effects of Further Processing,
Rework blending (Rework Quality & Quantity)Rework blending (Rework Quality & Quantity) Rubber processing equipments available & their Rubber processing equipments available & their condition.condition. The knowledge of Raw Materials used & their behavior during The knowledge of Raw Materials used & their behavior during
mixing and further processing is essentialmixing and further processing is essential
MIXING MIXING
Mixing Process is the base of Rubber Product Manufacturing Mixing Process is the base of Rubber Product Manufacturing Technology.Technology.
The success of subsequent processing & finished product The success of subsequent processing & finished product quality depends entirely on the quality & batch-to-batch quality depends entirely on the quality & batch-to-batch consistency of the mixed compounds.consistency of the mixed compounds.
‘‘Mixing’Mixing’ deals in deciding: deals in deciding: What equipment to use (speeds, pressures, temperature, time What equipment to use (speeds, pressures, temperature, time
cycles, procedures, etc. to blend the selected compounding cycles, procedures, etc. to blend the selected compounding ingredients into a properly mixed compound.ingredients into a properly mixed compound.
How to achieve High Degree of Dispersion and batch to How to achieve High Degree of Dispersion and batch to batch consistency.batch consistency.
MIXING
• Mixing process can be sub-divided into three stages :
1) Feeding ingredients to mixer (correct quantities at correct times at correct temperature.),
2) Actual Mixing of the ingredients,
3) Discharge of mixed compound and its shaping, cooling, packaging and storage for the next
process.
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MIXING Five main steps involved in the Mixing Operations :
1.1. Sub DivisionSub Division Of larger lumps & aggregates,Of larger lumps & aggregates,
2. 2. IncorporationIncorporation Of powders or liquidsOf powders or liquids
3. 3. DispersionDispersion Involves reduction of the size of agglomerates,Involves reduction of the size of agglomerates,
4. 4. Simple MixingSimple Mixing Involves moving particles from one point to another.Involves moving particles from one point to another.
5. 5. Viscosity ReductionViscosity Reduction By breakdown of the polymer and transforming it to By breakdown of the polymer and transforming it to desired viscosity.desired viscosity.
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• A good Dispersion rating requires :
High Shear Stress (i.e. High mix viscosity),
High Filler Loading,
Polymers of not too low viscosity,
Low Mixing temperatures,
Charging oils at the end of mixing cycle.
MIXING
• During Dispersive mixing, the carbon black agglomerates are broken down to less than 1 micron size.
• Dispersion largely depends on shear stress ( a critical value of shear stress is necessary to breakdown the agglomerates below which no dispersion action will take place).
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• To avoid scorching of compound; a two stage mixing procedure is used.
• Stage 1 - carbon black and other non vulcanizing
additives are combined with the raw rubber and
Higher mixing temperatures up to 160°C are used.
[The term Master Batch is used for first stage mixture]
• Stage 2 - After stage 1 mixing has been completed, and time for cooling has been allowed; stage 2 mixing is carried out in which vulcanizing agents are added. Lower mixing temperatures 90-100 °C are used.
Two-Stage Mixing in Internal Mixers
[The term Final Batch is used for second stage mixture]
NR Mastication & Blending NR+SR
• Mastication of NR to Optimum Degree and proper blending of Synthetic Rubbers with NR is Very Important .
• Ingredients which are difficult to disperse (e.g. hard carbon blacks, Ppt. silica, ZnO, etc) require Higher stock viscosity to disperse well.
Stock Viscosity Control is achieved through:
Compounding formulation design,
Close temperature control during mixing operations,
Use of specific sequence for addition of ingredients ,
Remixing of the stock after cooling.
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• Raw NR is dry & tough (Mooney Viscosity at 100°C > 80) and has to be masticated to a Workable Level of Mooney Viscosity of 50 to 60.
• Most Synthetic Rubbers are produced to a tailored Mooney viscosity (range 50 – 60) and hence ‘Mastication’ is not necessary.
• Keep Lower Mastication Temperatures when a Two-Roll mill is used (say, 60-70°C).
• Viscosity of Masticated NR should be closer to the Synthetic Rubber to be blended with it.
• NR-BR blends require higher shear rates for proper blending and hence Banbury / Intermix are more suitable than a mixing mill.
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EFFECT OF MASTICATION TEMPERATURE ON MOONEY VISCOSITY OF NREFFECT OF MASTICATION TEMPERATURE ON MOONEY VISCOSITY OF NR
MILLING MILLING TIME, MINTIME, MIN
MOONEY VISCOSITY (ML1+4 @ 100°C, UNITS)MOONEY VISCOSITY (ML1+4 @ 100°C, UNITS)
WITHOUT PEPTIZER WITHOUT PEPTIZER WITH PEPTIZER (DBD=0.5 PHR)WITH PEPTIZER (DBD=0.5 PHR)
@ 70°C@ 70°C @ 100°C@ 100°C @ 70°C@ 70°C @ 100°C@ 100°C
00 9595 9595 9595 9595
33 7676 8585 5858 5656
66 5757 8383 4040 4040
99 4747 6868 3333 2828
1212 4545 6565 3030 2424START TEMPERATURE, START TEMPERATURE, MOONEY VISCOSITY (ML1+4 AT 100°C), UNITSMOONEY VISCOSITY (ML1+4 AT 100°C), UNITS
OPEN MILL OPEN MILL (TIME = 8 MIN)(TIME = 8 MIN)
70 70 °C°C
100 100 °C°C
PEPTIZER = 0PEPTIZER = 0
5555
7575
PEPTIZER = 0.25PEPTIZER = 0.25
4242
4242
PEPTIZER = 0.5PEPTIZER = 0.5
3636
3737
INTERNAL MIXER INTERNAL MIXER (TIME 4 (TIME 4 MIN)MIN)
150 150 °C°C
160 160 °C°C
9090
8888
5454
4848
4242
3636
45
Mixing Mixing Time, Time, MinMin
Mixer Speed 25 rpmMixer Speed 25 rpm Mixer Speed 50 rpmMixer Speed 50 rpm
No Peptizer No Peptizer 0.1 Phr PCTP0.1 Phr PCTP No PeptizerNo Peptizer 0.1 Phr PCTP0.1 Phr PCTP
ML1+4@100°CML1+4@100°C ML1+4@100°CML1+4@100°C ML1+4@100°CML1+4@100°C ML1+4@100°CML1+4@100°C
00 9090 9090 9090 9090
22 7474 6969 6969 5252
44 68.568.5 6060 5050 3737
66 6767 5656 4242 2929
88 6565 5353 3434 --
1010 6161 5050 -- --Note the rapid reduction of Mooney viscosity at higher rotor speeds in the presence of chemical Peptizer at a very small dosage.
46
Effects of “Under Mastication” of NR
• Lower Mixing Cycles,
• High heat build up during mixing and subsequent steps,
• Poor extrudability / calendaring properties of the stock,
• Excessive shrinkage & dimensional control problems with extrudates / calendared stocks.
• Scorchy compounds.
• Excessive porosity in extrudates,
• Difficulties with ‘Rework’ blending,
47
Effects of “Over Mastication” of NR Lower shrinkage of extrudates / calendared sheets,
• Lower die swell & loss of dimensional control,
• Increased curing defects in finished products due to excessive flow and air entrapment,
• Compounded sheets stick to each other during storage and sagging of sheets,
• Excessive surface tack due to poor green compound strength,
• Loss of dynamic, tensile & tear strength properties of the vulcanizate,
• Changes in the viscosity of solvent based solutions & loss of surface tack.
48
MIXING
49
PROBLEMS & REASONSPROBLEMS & REASONS
PROBLEMSPROBLEMS REASONSREASONS
Poor DispersionPoor Dispersion
Batch size not optimized, mixing time is lower, filler Batch size not optimized, mixing time is lower, filler addition time not proper, insufficient ram pressure, poor addition time not proper, insufficient ram pressure, poor temp. control, poor / inconsistent raw material quality, temp. control, poor / inconsistent raw material quality, excessive moisture content in polymer and fillers, under / excessive moisture content in polymer and fillers, under / over mastication of NR.over mastication of NR.
Batch to Batch Batch to Batch VariationsVariations
Variation of start temp., variation in dump time and / or Variation of start temp., variation in dump time and / or temp. , poor dispersion, variation in ram pressure, temp. , poor dispersion, variation in ram pressure, variation in polymer / filler/ oil quality / rework quality, variation in polymer / filler/ oil quality / rework quality, under / over mastication of NRunder / over mastication of NR
Poor ProcessabilityPoor Processability
Compound viscosity not within controlled limits, under / Compound viscosity not within controlled limits, under / over mastication of NR, Processing temp. not under over mastication of NR, Processing temp. not under control, poor dispersion, higher loading of plasticizer / control, poor dispersion, higher loading of plasticizer / tackifiers / fillers/rework.tackifiers / fillers/rework.
Manufacturing processManufacturing process Unvulcanized rubber, whether natural or synthetic Unvulcanized rubber, whether natural or synthetic
behaves as a viscoelastic fluid during mixing. It is the behaves as a viscoelastic fluid during mixing. It is the operation required to obtain a thorough and uniform operation required to obtain a thorough and uniform dispersion of all ingredients called for by the formulae dispersion of all ingredients called for by the formulae in the rubberin the rubber
MachineryMachinery
2-roll mixing mill2-roll mixing mill
kneaderkneader
internal mixers internal mixers
Continuous, automatic high speed mixingContinuous, automatic high speed mixing
55
Capacities: Banbury MixersCapacities: Banbury Mixers
BanburyBanburyMixerMixer
Mixer Mixer ChamberChamber
Net Volume,Net Volume, ltrltr
Approx. Approx. Batch Wt *Batch Wt *
kgkg
Mixing Mixing SpeedSpeedRange,Range, RPMRPM
Torque rating Torque rating kW / RPMkW / RPM Approx. Approx.
MachineMachineWeight, MTWeight, MTCompact Compact
DriveDriveUniUni
DriveDrive
F 50F 50 5050 5050 40 - 12040 - 120 2.22.2 4.64.6 13.213.2
F 80F 80 8080 6060 30 - 10530 - 105 3.73.7 6.36.3 16.116.1
F 120F 120 120120 9090 30 - 9030 - 90 5.65.6 9.09.0 19.519.5
F 160F 160 160160 120120 20 - 8020 - 80 7.57.5 12.012.0 30.230.2
F 200F 200 200200 165165 20 - 6020 - 60 8.98.9 12.712.7 30.530.5
F 270F 270 270270 202202 20 - 6020 - 60 13.113.1 24.624.6 43.043.0
F 370F 370 414414 310310 20 - 6020 - 60 -- 37.337.3 54.054.0
F 440F 440 438438 330330 20 - 6020 - 60 -- -- --
F 620F 620 672672 500500 20 - 5020 - 50 -- 52.252.2 110.5110.5
( * Fill factor = 75% , S.G. = 1.0 )
56
Capacities: IntermixCapacities: Intermix
IntermixIntermix
Mixer Mixer ChamberChamber
Net Volume,Net Volume, ltrltr
Approx. Approx. Batch WtBatch Wt
kgkg
Mixing Speed, RPMMixing Speed, RPM Motor HPMotor HP
1-Speed , 2-Speed 1-Speed , 2-Speed
MachineMachineWeight, Weight,
MTMTSingle SpeedSingle Speed Two SpeedTwo Speed
K 0K 0 1.81.8 1.261.26 7676 75 / 15075 / 150 5, 5 / 105, 5 / 10 5.65.6
K 1K 1 5.55.5 3.93.9 40 / 14540 / 145 Variable driveVariable drive 5050 2020
K 2K 2 2020 1414 3030 22 / 4422 / 44 50. 50 / 10050. 50 / 100 5050
K 2AK 2A 4949 3434 3333 22 / 4422 / 44 150 , 75 / 150150 , 75 / 150 6060
K 4K 4 9191 6464 3333 22 / 4422 / 44 220, 50 / 300220, 50 / 300 9898
K 5K 5 143143 100100 3333 22 / 44322 / 443 300, 200 / 400300, 200 / 400 140140
K 6K 6 206206 144144 3333 22 / 4422 / 44 475, 320 / 640475, 320 / 640 235235
K 6AK 6A 257257 180180 3333 22 / 4422 / 44 500, 350 / 700500, 350 / 700 280280
K 7K 7 310310 217217 3333 22 / 4422 / 44 750, 500/1000750, 500/1000 310310
K 8K 8 498498 349349 3333 22 / 4422 / 44 -- --
( * Fill factor = 70% , S.G. = 1.0 )
Dry rubber based productsDry rubber based products
Mix and Compound DesignMix and Compound Design
For manufacture of dry rubber products, the For manufacture of dry rubber products, the following minimum process steps are essentialfollowing minimum process steps are essential
compoundingcompounding shapingshaping vulcanization vulcanization
MIXING PROCEDUREMIXING PROCEDUREWeighing compounding ingrediants as per
formulation
Mastication
Compounding And Homogenisation
Maturation
DRY RUBBER PRODUCTS MANUFACTURE
RUBBERCOMPOUNDIN
GCHEMICALS
MATURATION
PRE-WARMING
TESTING& QC
MOULDED GOODS EXTRUDED GOODS CALENDERED GOODS