Review of Rubber Mixing Effect on Polymer / Compound ... Review of ruber mixing.pdf · Review of...

Review of Rubber Mixing&

Effect on Polymer / Compound Performance

ERIF 2017Vienna: 10. – 11. May

Dr. Hans-Joachim Graf 2

Raw materials

Form

ing-

pro

cess

Mixin

g

pro

cess

Chan

ges

in th

e pro

cess

of m

ixing

The behavior

of raw materials

Effectson the process

Formula

IntroductionMixing of SBRMixing of NR/BR/SBRMixing of EPDMCB Dispersion in SBRConclusion

Review of Mixing


Mixing gives reason to changes of ingredients and of reactions between the ingredients Mixer behaves like a reactor In addition to mechanical work on distribution and dispersion

Polymer Changes MW, MWD and LCB Radical reactions of polymer with Carbon Black

Protection / Processing Aids Ingredients with functional groups reacting with polymer Acid / Base Reactions


Review of Mixing


Mixing What is the goal of Mixing? Compound, which can be

processed in the desired machines, turned into a part, which meets customer expectations

Viscosity of compound – processing

Dispersion of Filler – physical properties

Homogeneity Rheology – Cure kinetic

US 2820836 A


Review of Mixing


Mixing What is the conflict in Mixing? Viscosity of compound:

Viscosity correlates to MW: Performance – Higher is betterProcessing –

Lower is better: IM Higher is better: CM, Extrusion

Dispersion of Fillers Temperature rise through high

shear correlates to: MW (+ Type of Polymer),

Filler (Type) / Oil loading Rheology – Cure kinetic

PolymerType / MW

LoadingOil / Filler

FillerType / Size


Review of Mixing


Source: Nijmann Vredestein

Mixing Diagram Information Ram Down Ram Down / Up / Down

Mixer under filled Mixer slightly under filledMastication Mixing Oil injection


Review of Mixing


Source: Thesis Ebell

Process factorsin order of importance Mixing Time or Mixing Unit Work

Rotor Speed

Mixer Temperature

Ram Pressure

Fill Factor (not independent from Ram Pressure)


Review of Mixing


Source: Sommer, R Handbook

Mixing / molecular weight change MW of different NR-

Types coagulated and stabilized

Bimodal MW distribution

MWD of 5 - 10 Mastication on Mill of

SMR 20 MW decreases Bimodal MW

distribution becomes a broad MW

Log M


Review of Mixing

Dr. Hans-Joachim Graf

Source: Thesis Ebell

*) other factors neglected

*) Mixing of SBR:


Review of Mixing


Mooney Viscosity (Mooney Units)

Tens

ile s

tren

gth

(MPa

)

25

23

22

21

120°C160°C190°C

Dependence of physical properties on Mooney viscosity of masticated SBR rubber and on temperature of mastication.

Source: Martin, RCT 1955Fig left: Thesis Ebell

Mixing of SBR:


Review of Mixing


Source: Ebel, Thesis

Mixing of SBR:


Review of Mixing



Mixing of SBR: Mix Time over Unit Work & Rotor Speed Ram pressure 0.22 (left) - 0.80 (right)

Design-Expert® SoftwareFactor Coding: ActualOriginal Scale (median estimates)Mix Time

Design points above predicted valueDesign points below predicted value453.89

75.30

X1 = A: Unit WorkX2 = B: Rotor Speed

Actual FactorsC: Fill Factor = 0.80D: Ram Pressure = 0.40E: Temp Mixer = 50.00

45.00 51.00

57.00 63.00

69.00 75.00

600.00 675.00

750.00 825.00

900.00 975.00

1050.00 1125.00

1200.00

100.00

200.00

300.00

400.00

500.00

M

ix T

ime

A: Unit Work

B: Rotor Speed

Design-Expert® SoftwareFactor Coding: ActualOriginal Scale (median estimates)Mix Time

453.89

75.30



45.00 51.00

57.00 63.00

69.00 75.00

600.00 675.00

750.00 825.00

900.00 975.00

1050.00 1125.00

1200.00

100.00

200.00

300.00

400.00

500.00

M

ix T

ime

A: Unit Work

B: Rotor Speed


Review of Mixing



Mixing of SBR: Dump Temperature over Unit Work & Rotor Speed Ram pressure 0.22 (left) - 0.80 (right)

Design-Expert® SoftwareFactor Coding: ActualDump Temp

Design Points169

92



600.00 675.00 750.00 825.00 900.00 975.00 1050.00 1125.00 1200.00

45.00

51.00

57.00

63.00

69.00

75.00Dump Temp

A: Unit Work

B: R

oto

r S

peed

140

145

150

157

Design-Expert® SoftwareFactor Coding: ActualDump Temp

Design Points169

92



600.00 675.00 750.00 825.00 900.00 975.00 1050.00 1125.00 1200.00

45.00

51.00

57.00

63.00

69.00

75.00Dump Temp

A: Unit Work

B: R

oto

r S

peed

125

130 135

140

145

150


Review of Mixing



Mixing of SBR: Tensile over Unit Work & Rotor Speed Ram pressure 0.22 (left) - 0.80 (right)

Design-Expert® SoftwareFactor Coding: ActualTensile

Design Points12.40

4.47



600.00 675.00 750.00 825.00 900.00 975.00 1050.00 1125.00 1200.00

45.00

51.00

57.00

63.00

69.00

75.00Tensile

A: Unit Work

B: R

oto

r S

peed

6.00

7.00 8.00

9.00

10.00

Design-Expert® SoftwareFactor Coding: ActualTensile

Design Points12.40

4.47



600.00 675.00 750.00 825.00 900.00 975.00 1050.00 1125.00 1200.00

45.00

51.00

57.00

63.00

69.00

75.00Tensile

A: Unit Work

B: R

oto

r S

peed

7.008.00

9.00

6.50


Review of Mixing



Mixing of SBR: Tensile: Predicted versus Actual (left) Mooney Viscosity: Predicted versus Actual (right)


Review of Mixing

Design-Expert® Software1/Sqrt(Tensile + 0.50)

Color points by value of1/Sqrt(Tensile + 0.50):

0.45

0.28

Actual

Pred

icte

d

Predicted vs. Actual

0.25

0.30

0.35

0.40

0.45

0.25 0.30 0.35 0.40 0.45

Design-Expert® SoftwareMooney Visc

Color points by value ofTemp Mixer:

50.00

30.00

2

22 2 3

Actual

Pred

icte

d


50.00

60.00

70.00

80.00

90.00

50.00 60.00 70.00 80.00 90.00



Design-Expert® SoftwareFactor Coding: ActualOriginal Scale (median estimates)Overlay Plot

Mix TimeDump TempMooney ViscTensile

Design Points



600.00 675.00 750.00 825.00 900.00 975.00 1050.00 1125.00 1200.00

45.00

51.00

57.00

63.00

69.00

75.00Overlay Plot

A: Unit WorkB

: R

oto

r S

peed

Mix Time: 210.000 Mix Time: 230.000

Dump Temp: 156.000

Dump Temp: 160.000

Mooney Visc: 65.000Mooney Visc: 67.000

Tensile: 9.500

Tensile: 10.300

Mixing of SBR: Unit Work over Rotor Speed Tensile at 10.3 MPa (max. value) Mixing time 210 – 230 sec Mooney viscosity ML(1+4) 100°C: 65 – 67 Mooney Units


Review of Mixing


Source: Kreuzwieser, Thesis

Mixing of NR/SBR/BR: Ml(1+4)100°C over Mixing Time & Rotor Speed Mastication time 30 sec (left) 70 sec (right)

Design-Expert® SoftwareFactor Coding: ActualML(1+4)100

Design points above predicted valueDesign points below predicted value62

45

X1 = B: mixing X2 = C: rotor speed

Actual FactorA: Mastication = 30.00

35.00

41.00

47.00

53.00

59.00

65.00

3.50

4.10

4.70

5.30

5.90

6.50

40

45

50

55

60

65

ML(

1+4)

100

B: mixing C: rotor speed

Design-Expert® SoftwareFactor Coding: ActualML(1+4)100


45



35.00

41.00

47.00

53.00

59.00

65.00

3.50

4.10

4.70

5.30

5.90

6.50

40

45

50

55

60

65

ML(

1+4)

100



Review of Mixing



Mixing of NR/SBR/BR: Specific Energy Mix over Mixing Time & Rotor Speed (left) Correlation of Mooney with Specific Energy Mix (right)

Design-Expert® SoftwareFactor Coding: ActualE spec. Mixing


179



35.00 41.00

47.00 53.00

59.00 65.00

3.50 4.10

4.70 5.30

5.90 6.50

100

200

300

400

500

600

E s

pec.

Mix

ing


Specific Mixing Energy over Mooney Ml(1+4)100°C

Mooney - ML(1+4)100°C [MU]44 46 48 50 52 54 56 58 60 62 64

Spec

ific

Ener

gy [W

h/kg

]

100

200

300

400

500

600

Ml(1+4) vs E spec Mix


Review of Mixing



Mixing of NR/SBR/BR: Extrusion over Mixing Time & Rotor Speed

(Extrusion Experiment at constant Screw speed 50 rpm) Extrusion Motor power consumption (Nm) (left) Extrusion Head Pressure (bar) (right)

Extruder Output at 50 rpm is invariant towards head-pressure.

Design-Expert® SoftwareFactor Coding: ActualExtr 50rpm 100°C


44



35.00

41.00

47.00

53.00

59.00

65.00

3.50

4.10

4.70

5.30

5.90

6.50

40

45

50

55

60

Ext

r 50r

pm 1

00°C


Design-Expert® SoftwareFactor Coding: ActualExtr Press


60



35.00

41.00

47.00

53.00

59.00

65.00

3.50

4.10

4.70

5.30

5.90

6.50

55

60

65

70

75

80

85

Ext

r Pre

ss


Design-Expert® SoftwareFactor Coding: ActualExtr Output


57.8



35.00 41.00

47.00 53.00

59.00 65.00

3.50 4.10

4.70 5.30

5.90 6.50

56.0

58.0

60.0

62.0

64.0

66.0

Ext

r Out

put



Review of Mixing



Mixing of NR/SBR/BR: Tensile Strength over Mixing Time & Rotor Speed

Mastication time has little to none influenceDesign-Expert® SoftwareFactor Coding: ActualTS


16.2



35.00 41.00

47.00 53.00

59.00 65.00

3.50 4.10

4.70 5.30

5.90 6.50

16.0

17.0

18.0

19.0

20.0

TS



Review of Mixing



Mixing of NR/SBR/BR: CB Distribution over Mixing Time & Rotor Speed

30 sec Mastikation time – (left) 50 sec Mastikation time – (right)

70 sec Mastikation time – (lower right)

Design-Expert® SoftwareFactor Coding: ActualCB Dispersion


20



35.00

41.00 47.00

53.00

59.00 65.00

3.50 4.10

4.70 5.30

5.90 6.50

-20

0

20

40

60

80

100

120

CB

Dis

pers

ion




20



35.00

41.00

47.00

53.00

59.00

65.00

3.50 4.10

4.70 5.30

5.90 6.50

-20

0

20

40

60

80

100

120

CB

Dis

pers

ion




20



35.00 41.00

47.00 53.00

59.00 65.00

3.50 4.10

4.70 5.30

5.90 6.50

-20

0

20

40

60

80

100

120

CB

Dis

pers

ion



Review of Mixing



Mixing of NR/SBR/BR: Factors: Mixing Time over Rotor Speed Response: Optimization

Head Pressure / Specific Mixing Energy CB- Dispersion / TS (Tensile strength) / Mooney Viscosity

Design-Expert® SoftwareFactor Coding: ActualOverlay Plot

ML(1+4)100E spec. MixingE spec ExtrudExtr Motor PowerExtr Head PressTSCB Dispersion

Design Points



3.50 4.10 4.70 5.30 5.90 6.50

35.00

41.00

47.00

53.00

59.00

65.00Overlay Plot

B: mixing

C: r

otor

spe

ed

ML(1+4)100: 45.000

E spec. Mixing: 444.034

Extr Motor Power: 51.000

Extr Head Press: 60.000


TS: 19.000CB Dispersion: 80.000



Design Points



3.50 4.10 4.70 5.30 5.90 6.50

35.00

41.00

47.00

53.00

59.00

65.00Overlay Plot

B: mixing

C: r

otor

spe

ed

ML(1+4)100: 45.000




TS: 19.000

CB Dispersion: 80.000

5



Design Points



3.50 4.10 4.70 5.30 5.90 6.50

35.00

41.00

47.00

53.00

59.00

65.00Overlay Plot

B: mixing

C: r

otor

spe

ed




TS: 19.000

CB -Dispersion


Review of Mixing


Mixing Time – VAW concentration Tire Tread Compound

Source: Kreuzwieser Thesis


Ml(1+4) 100Fmax-FminEspec Mix Espec EtrudM100M300TSEB

Design Points

X1 = B: Mix TimeX2 = A: VAW

126.00 135.00 144.00 153.00 162.00 171.00 180.00

0.00

0.70

1.40

2.10

2.80

3.50

4.20

4.90Overlay Plot

B: Mix Time

A: V

AWMl(1+4) 100: 59.000

Ml(1+4) 100: 63.076

Fmax-Fmin: 0.580

Espec Mix : 142.000

M100: 1.500

TS: 11.000TS: 12.000

EB: 500.184

EB: 560.748

TS

Mooney


Review of Mixing


Source: Nijmann Vredestein

Effect of Polymer Structure on Mixing Influence of branching Power consumption of the mixer and batch temperature in the

mixing phase due to EPDM LCB (Mixer: W&P, GK90E, Rotor PES3)


Review of Mixing


Viscosity Drop during mixing Mastication of EPDM

Change of MW Distribution curve depends on MW and MWD

Most rubbers show decrease in viscosity, if exposed to mechanical and heat energy.

Molecular weight curve will change it size and form!

Source:HJ Graf, KHK 2002

GPC Eluation Time

GPC

-MW


Review of Mixing


Source: S.Yu, H-J Graf

MW decrease of EPDM Due to mixing there is a shift of

GPC average MW(Note the GPC-MW / Mooney Correlation)

Polymers of different origin behave different

High MW Polymers effected more than low MW Polymers

3,00 3,50 4,00 4,50 5,00 5,50 6,00 6,50 7,00

0,0000

0,1000

0,2000

0,3000

0,4000

0,5000

0,6000

0,7000

0,8000

0,9000

1,0000

Polymer "D"

Polymer "D" Sheared

log (M)

dwt(

M)/d

logM


Review of Mixing


Mixing experiment with EPDM low (left) MW / high MW (right)Tensile strength [MPa]

Source: HJ Graf


Review of Mixing


Mixing experiment with EPDM low (left) MW / high MW (right)Crack Growth 25 (top) / 35 (bottom) (mm/cycle 10^-5)

Source: HJ Graf


Review of Mixing


Mixing experiment with EPDM low (left) MW / high MW (right)Fatigue to falilure (cycles)

IntroductionEffects of mixing on PolymerIncorporation of FillersMixing of OilInteraction of IngredientsAcceleration in the mixer / millMixing Recipe Design in consideration of formula Summary

Function / Use of Process AidsMixing of CompoundMeeting a SpecificationCompound to CostMethods in DevelopmentCompound DoE&SimulationReverse DevelopmentCompound Exercises Source: HJ Graf


Source: Cotten, RCT 58

Influence of CB PropertiesPolymer CB-441 at loading of CB 50 phr


Review of Mixing


Source: Hess, RCT 57

Properties of Carbon Black influence the mixing process and the properties of the compound DOE with Carbon blacks

DOE map according to available CB grades

CB-Dispersion on SBR 1500 compound as a function of CB surface area and DBPA at to different mixing procedures

CB and oil added separately CB added with black

SBR 1500 with60 phr CB37,5 phr oil

According to modern DoE Programs: lack of statistic significance.


Review of Mixing



Addition of Oil In some rubbers oil must

be added separately to achieve proper dispersion of CB

SBR 1500 needs separate addition of oil.

Otherwise compound will not take up enough shear for dispersion

According to modern DoE programs lack of statistic significance

SBR 1500 Compound with 10 phr, 25 phr and 40 phr Oil


Review of Mixing



SBR 1712 – Mixing dependent on CB DBPA-Absorption & N² Surface But the Statistic models are not significant

Design-Expert® SoftwareFactor Coding: ActualMix Time 120rpm


3.0

X1 = A: DBPAX2 = B: N²surface

20.00

46.00

72.00

98.00

124.00

150.00

50.00

75.00

100.00

125.00

150.00

2.0

3.0

4.0

5.0

6.0

7.0

Mix

Tim

e 12

0rpm

A: DBPA

B: N²surface

Design-Expert® SoftwareFactor Coding: ActualMix Time 80rpm


4.1

X1 = A: DBPAX2 = B: N²surface

20.00

46.00

72.00

98.00

124.00

150.00

50.00

75.00

100.00

125.00

150.00

3.0

4.0

5.0

6.0

7.0

8.0

Mix

Tim

e 80

rpm

A: DBPA

B: N²surface


Review of Mixing



SBR 1712 – Mixing dependent on CB DBPA-Absorption & N² Surface ??? But the Statistic models are not significant

Mix Energy to 95% Dispersion – Predicted vs Actual (left) But Correlation of Dispersion Index with Factors are significant (right)


Review of Mixing

Design-Expert® SoftwareMix Energy 95DI

Color points by value ofMix Energy 95DI:

1800

935

Actual

Pred

icte

d


800.00

1000.00

1200.00

1400.00

1600.00

1800.00

800.00 1000.00 1200.00 1400.00 1600.00 1800.00

Design-Expert® SoftwareDisp-Index

Color points by value ofDisp-Index:

95

74

ActualPr

edic

ted


70.00

75.00

80.00

85.00

90.00

95.00

100.00

70.00 75.00 80.00 85.00 90.00 95.00


Source: Exxon

Filler / Oil ratio of Rubber due to processing window in mixing Viscosity (or MW) dependent ability to load with carbon black and

oil


Review of Mixing


Conclusion / Important to remember:

SBR requires high rotor speed and longer mixing timeresp. Energy input

NR (Blend) requires medium to high rotor speed and sufficient time for maximum performance.Temperature should be kept under control

EPDM requires lower rotor speed and mixing time as short as possible

Carbon Black Dispersion experiment should be re developed (statistic significance not sufficient)We should redo this experiments!

Source of Slide: Exxon


Review of Mixing

Rubber Injection MoldingFolie 2Folie 3Folie 4Folie 5Folie 6Folie 7Folie 8Folie 9Folie 10Folie 11Folie 12Folie 13Folie 14Folie 15Folie 16Folie 17Folie 18Folie 19Folie 20Folie 21Folie 22Folie 23Folie 24Folie 25Folie 26Folie 27Folie 28Folie 29Folie 30Folie 31Folie 32Folie 33Folie 34Folie 35Folie 36Folie 37Folie 38

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