Mezclado Del Caucho

7/26/2019 Mezclado Del Caucho

1/72

Update in Rubber Mixingand

Rubber Technology

R. H. Schuster

Consultant to LANXSS !"er#an Rubber $nstitute

%& 'ornadas Latino(A#ericanas de Caucho

)uenos Aires &*!&+ Sept. &,%*


2/72

%.-ay( Mixing o Rubber

( /iller -ispersion

( /iller -istribution

( Rubber(/iller $nteraction( $nluence o Mixing on

-yna#ic(Mechanical 0roperties

&.-ay( $nluence o Mixing on Ulti#ate 0roperties

( 1ulcani2ation3 Che#istry and 0rocess

( Speciality Rubbers( 4xidati5e Ageing

( 4il Resistant T01


3/72

Abrasion Resistancenergy -issipation

lasticity

Lo6 Te#perature /lexibility

Ageing Resistance

Tensile Strength

7earResistance

4il Resistance

Traction

lasto#ers


4/72

lasto#ers

Tires

8&9.,,, t

:.%,, Mrd ;

Technical Rubber "oods?=&.,,, t

:.+,, Mrd ;

< &9 >Source3 7d@ Report &,%,


5/72

Mixing o

Rubber Co#pounds


6/72

Aggregates

Agglo#erates

/illerManuacturing

0elletslarge size

hardness and strengthlow density (voids)

stability in pneumatic transport

Role o Mechanical Mixing

$ncorporation

Si2e reduction

0ellets

Aggregates


7/72

MixingMaterial properties changing 0rocess

( Rheological 0roperties

( /urther 0rocessing( -ispersion and -istribution o /illers

( 0hase Morphology

( 0hysical 0roperties Set

( Lie Ti#e o Rubber 0roducts


8/72

0art 0ropertiesMixing Co#pound0roperties

0rocessing 0art 0ropertiesMixing Co#pound0roperties

0rocessing


9/72

/urther0rocessing/urther0rocessing

0oly#ersB

/illersB

0rocess oilsB

Special Che#icals

Curing Agents

Mixing 0rocess

( Mastication and )lending( $ncorporation o /illers

( /iller -ispersion!distribution

( -ispersion o ingredients

( 4il incorporation

( Curing reaction is not allo6edto start

Mixing 0rocess

( Mastication and )lending( $ncorporation o /illers

( /iller -ispersion!distribution

( -ispersion o ingredients

( 4il incorporation

( Curing reaction is not allo6edto start

Ra6 Material

uality Control

Ra6 Material

uality Control

uality checDo the #ixtureuality checDo the #ixture

0urpose o the Mixing 0rocess


10/72

Rating Criteria or Mixing uality

-egree o /iller -ispersion

Methods do not allo6 any in(process control

Retroacti5e inor#ation E

Tensile Strength

Tear 0ropagation Resistance


11/72

Mixing Fuip#ent

-iscontinuous Mixing

)atch Mixing

Continuous Mixing

T6o(Roll Mill

$nternal Mixer

T6in Scre6 xtruder

Ring xtruder

0lanetary Roller xtruder

6ell established

State o the Art

pro#ising starts or

so#e production lines

Can use e5ery or#

o the ra6 #aterials

Relies #erely on

ree lo6ing ra6 #aterials

i.e. granulates


12/72

T6o(Roll Mill

#illing o rubber sheets

Cutting o the blanDet

-ierent speed o the rolls

/rictionB

Stea#(heating

/or#ation o a band 6hich

adheres to one o the rolls

Mixing iciency is high

High strains in the Nip region

stocD

blender

T6o rolls 6hich rotate in

opposite sensed6in ChaeG %9*:B

Cooling


13/72

Mixing on an open #ill

Courtesy3 1redestein


14/72

T6o(Roll Mill

Ad5antages

-ispersi5e Mixing actionis high

Mixing 0rocess isollo6ed easily

Mixed Material or#s

sheets suitable or

Co#pression Molding

-isad5antages

Handling o /illers andAdditi5es cause house(

Deeping proble#s

0rolonged Mixing Ti#es

Less 0rocess Control

xposure o large

suraces to at#osphere


15/72

$nternal Mixer I )rie History


16/72

$nternal Mixer

Closed Mixers eFuipped 6ith

counter(rotating rotors

Rotors 6ith ascre6(liDe geo#etry

Axial #ixing along the

rotors to6ards the center

Ra#3( seals the #ixing cha#ber

( 0resses 0oly#ers into

the #ixing cha#ber

( co#press large 5olu#es

o illers

Rotors #ay or

#ay not o5erlap


17/72

$nternal Mixer I basic ele#ents

Modular design

( /eeding hopper( Mixing cha#ber

( )ase 0late

Mixing Cha#ber

( Mixing cha#ber hal5es( Rotor end plates

( Rotors

Te#perature Control

Cooling syste#s


18/72

$nternal #ixers in tyre industry adopt #aterials

in any Dind o trade or#

Courtesy3 Harburg /reudenberger Maschinenbau "roupor#erly @rupp ! 70B


19/72

$nternal #ixers or technical rubber goods


20/72

Types o $nternal Mixers

Tangential Rotors $nter#eshing Rotors

( The rotors do not o5erlap

( Cur5ed lights 6hich

pu#p in opposite direction

( $ndependent speed on each

rotor( "ap bet6een the rotors a5ours

i#pro5ed eeding

( larger batch 5olu#e

( Short incorporation ti#e

( The rotors o5erlap

( $nter#eshing o the

rotor lights

( s#all interdistance

( sa#e angular 5elocity( high surace!5olu#e ratio

( )etter cooling

( Less batch 5olu#e

( "ood dispersi5e #ixing


21/72

,

%

&

*

+

:

?

nergy

..iciency

Ther#al

0er.or#ance

Co(#astication 0lastici2er

)lending

Machine

Utili2ation

$ntaDe and

-ischarge

)eha5ior

,

%

&

*

+

:

?

nergy

..iciency

Ther#al

0er.or#ance

Co(#astication 0lastici2er

)lending

Machine

Utili2ation

$ntaDe and

-ischarge

)eha5ior

Tangential

$nter#eshing

Technological Co#parison $B


22/72

Sa#e batch si2e

courtesy3 Techint 0o#ini

tangential $nter#eshing

Technological Co#parison $$B

,

:,

%:,

&:,

*:,

% & * + : ? =Cooling Surace J# K

1oid1

olu#eJ#L

tangentialinter#eshing

,

:,

%:,

&:,

*:,

% & * + : ? =Cooling Surace J# K

1oid1

olu#eJ#L

tangentialinter#eshing


23/72

Tande# Mixing

Co#bination oa #aster batch #ixer $nter#ixB

a larger ra#less #ixer Tande#B

eecti5ely cooled

inter#eshing rotors

Consecuti5e #ixing

Rubber and /iller into the hot

$nter#ix upper #ixerB

Ater pre#ixing the co#pound is

dropped into the tande# #ixer.

Mixing ti#e reducedCooling and -ispersion

by re#illing in the Tande#

'. 0eter %89=B


24/72

Tande# Mixing

/ro# Tande# MixerThe inal batch is du#ped

on a #ill or into an

extruder 6ere it 6ill

be sheeted andcon5eyed to the batch Io

unit.

Ad5antage3

%B the batch does

not need to be stored bet6een

%st and &nd stage

&B )etter te#perature controli.e. or Silani2ation

*B Higher troughput

-ischarge

%%,C

Add Curati5es

Te#p.


25/72


26/72

/eeding Hopper3 Concepts

0neu#atic /eeding Hopper Hydraulic /eeding Hopper


27/72

Hydraulic /eeding Hopper

Lo6 noise

le5el

/ast ra#

#o5e#ent 0recise ra# orce

control

Little operation

costs

Constant process

conditions

Ad5antages o Hydraulic /eeding Hopper


28/72

Ra# 0osition Control

Usually ra# speedG ra# pressure are adOusted during theinstallation o the #ixer

0roble#s or hopper unctionality3

( -usty illers can deposit on the ra#( SticDy co#pounds on the hopper 6alls

( Ra# Oa##ing

-igital ra# position control

( Co#pound Fuality can

be i#pro5ed

( 4peration disruptions can

be a5oided

-epending on the ra# positionG ra# speed

and ra# pressure can be better controlled


29/72

Mixing Cha#ber $B

Hard Coating

Hard Coating

ree o CracDs

Corosion

Resistance

High tensile

Strength

$ntensi5e Cooling

High Hardness

Fual coating

thicDness


30/72

Mixing Cha#ber $$B

Te#perature ControlTe#perature recording is aected by

( Co#pound lo6

( good ther#al contact

( extension o the sensor( place#ent in side6all or drop door

( Sensiti5ity o the sensor


31/72

Mixing Cha#ber $$$B

0lastici2er 4il $nOection

/eeding liFuid co#ponents into the #ixing cha#ber

$nOection 5al5es are itted into the #ixing cha#ber

Large #ixers are eFuipped 6ith + inOection 5al5es

$nOection in short ti#e and dierent types o plastici2er


32/72

Rotors

/unctions o the Rotors

$#part shear and elongation into the co#pound

-ispersi5e Mixing

-istribute ingredients inside the co#pound

-istributi5e Mixing

-issipate heat out o the co#pound

C li


33/72

Cooling

Ring cooling

Spray cooling

Rotors occupy a high portion

o the #ixing cha#ber

Cooling o rotors i#pro5es

#ixing eiciency by

increasing the 5iscosity

o the #ix.

Strength is achie5ed by rotorbody 6alls

)etter cooling eiciency 6ith

Ring cooling.T6o body rotor 6ith reduced 6all

ThicDness. "ood heat transer


34/72

Tangential Rotors $BTangential Rotors in5ented by

/. H. )anbury

-ia#etrical located

one 6ing extended in length

Relati5e lo6 producti5ity

Most eecti5e #ixing

bet6een the rotor lights and the 6all

0articular eatures or tangential Rotors

( Nu#ber o 6ings

( 0osisition o 6ings( Length o 6ings

( Angularity o 6ings

( 4utline acti5e!passi5e sideB

(Tip 7idth o the 6ings


35/72

Tangential Rotors $$B

&(7ing RotorsLasch P /rei %8*,B

Nor#al Rotor StandardB

( Short 6ings are s#aller in height

( used in older #ixers

/ull(+(7ing Rotors /(+ I7B Tyson and Co#perG %8??B

& long #ain 6ings 6ith

( short pitch angle and large light depth

( & shorter 6ings at higher pitch angle

High speciic energy in a

short period o ti#e

Rapid #aterial intaDe and

good discharge 0roperties

N (Rotors

Un6ined

Rotor "eo#etry

/ull(+(7(Rotors

Un6ined

Rotor "eo#etry


36/72

Tangential Rotors $$$BST (Rotor Synchronous TechnologyNortey %89=B

+(6ing rotor 6ith special geo#etry

ach long and each short light

starts at another end o the rotor.

$#pro5ed #ixing peror#ance

)est 6ith e5en speed o the rotors

QQ &(Rotor7iede#ann P Sch#idt %89&B/light Angle at +,

Length o he light is shorten

-istributi5e #ixing capacity

Te#perature control-ischarge te#perature is reduced

*, > throughput than N(rotor

Mixes or Technical Rubber "oods


37/72

Tangential Rotors $1B

High -ispersion Super Cooled H-SCB

Long 7ings are extended to

9,> o the rotor length

The 6ing arrange#ent supportsThe lo6 o5er the 6ing tips

Application in tire industry

Maxi#u# -ispersion Super Cooled M-SCB

/our 7ings unior#ly distributed

Spiral cooling

1ery agressi5e rotors

Master )atch Mixing in tire industryHigh producti5ity and good

dispersion


38/72

Tangential Rotors 5B

? I7ing(Rotor

"ood #ixing peror#ance

/aster #ixing cycles

1iscosity is reduced aster"ood Co#pound Fuality


39/72

$nter#eshing Rotors

CooDeG %8*+

ach rotor eFuipped 6ith

one helical 6ing extended

o5er the ull length o the rotor

$nterlocDing Technology'ohnson %89,B

Long 6ing o helical or#ation

7ide 6ing tipT6o s#aller 6ings are radially

Spaced beore and ater the long

7ing.


40/72

$nter#eshing Rotors

0S Technology7iede#ann P Sch#idt %89&B

0artielle 5ol5enten Schauel

0S(* Rotor

$ncreased 6idth o the 6ing tips

Material lo6 bet6een the

Counter(rotating rotors"ood dispersi5e Mixing


41/72

Mixer )ase 0late

To absorb orces bearing upon

$ndi5idual co#ponents

High torsional stability and lo6 6eight

-rop -oor and Latch


42/72

0rocessing Aspects o

Rubber Mixing

/or# o the Main Co#ponents


43/72

Rubber )ales

Acti5e /illers0elleti2ed Materials

/or# o the Main Co#ponents

Sotener!0lastici2er

Changes in Material 0roperties


44/72

0oly#er Carbon blacD 4perating para#.

-eor#ation beha5iour

ield point

7all slippage

7all adhesion

Surace acti5ity

Agglo#erate si2e

Strength o

agglo#erate

Rotational speed

"eo#etry

Ra# pressure

/ill actor

Ther#al boundary

conditions

/eed seFuences

Result o #ixing -egree o dispersion

/luctuations in 5iscoelasticity

Ther#al loading

Material beha5iour during #ixing /eed in beha5iour

Te#perature proile

Change in #aterial properties

I 5iscoelasticity I heat capacityI density I heat transer

$ncorporation and

dispersion o carbon blacD

or other illers

Changes in Material 0ropertiesduring Mixing


45/72

-ispersi5e Mixing

)reaD(do6n o 0article!-o#aine Si2e/or#ation o large $nterphases

-istributi5e MixingHo#ogeni2ation o ingredients

5en concentration o ingredient

longational/lo6

ShearStress

Ti#e

No )reaDage

)reaDage

La#inar Mixing$ncreased interace bet6een

t6o layers

shear strain

/lo6 pattern in an internal #ixer


46/72

$nluences to /lo6

( rotor geo#etry

( angle o the rotor blades

( nu#ber o the #ainand side blades

( ill actor

/lo6 pattern in an internal #ixer

FrontWall(PeriphericalDirection)

Axial Direction

A

B

C

II

III

I

mA

mB

LeaDage /lo6

Con5erging /lo6

Material can be transportediB rotationally 6ith the rotor light

iiB through the gap bet6een

the 6ing tip and the cha#ber 6all

iiiB along the light and pass

around the rotor end

-istributi5e and -ispersi5e Mixing Qones


47/72

-istributi5e and -ispersi5e Mixing Qones

around the Rotor 7ing


48/72

Mixing Cycleand

$nluence o Material 0ara#eters

Masterbatch Mixing Cycle


49/72

:

4il inOection

%

0oly#er

charging

&

Mastication

*

/iller

charging

+

/iller

incorporation

?

Ra#

s6eep

=

Ater

#ixing

9

-ischarge

Masterbatch Mixing CycleMastication

$ncorporation -ispersion -istribution

$ncorporation o the /iller


50/72

/iller is incorporated into the Rubber

Reduction o total 1olu#e o the Mix

-ispersion is not satisactory

$ncorporation o the /iller

$ncorporation Ti#e

depends on3( type o /iller

( type o Rubber

( content o oil

( type o Mixer( 0rocessing 0ara#eters

Rubber /iller

$ncorporated /iller

xa#ple o a #ixing process opti#ised


51/72

,

:,,

%,,,

%:,,

&,,,

, :, %,, %:, &,, &:,

time (s)

Powersupply

(kW)

,

:,

%,,

%:,

&,,

Temperature

(C)

0o6erRa# position

A5g 0o6er

Te#perature

1 2 3 7654 8

Mixer3

"@+,,N

Rotor3

+ 7ing

/ixed speed

xa#ple o a #ixing process opti#ised

or throughput

". NiO#anG -$@ Se#inar &,,=

0o6er -e#and or Mastication


52/72

?

9

%,

%&

%+

%?

&, +, ?, 9,

0oly#er -osing Te#perature CB

0o6er0eaDJD7

hL

0o6er -e#and or Mastication

Ra# Setting3 Rubber Te#perature


53/72

*, +, :, ?, =, 9,

Rotor Speed

Ra

#

SettingTi#e

+,

?,

9,

%,,

%&,

*, +, :, ?, =, 9,

Rotor Speed

Ra

#

SettingTi#e

+,

?,

9,

%,,

%&,

g p

*, C

?, C8, C

Ra# Setting3 $nluence o C)


54/72

Lecture04A%%.,?.&,,=:+

Ra#-

isplace#ent

Mixing Ti#e t Mixing Ti#e t

Ra#-isplace#ent

ect o /iller Loading ect o /iller Structure-)0B

N *+=

N **,

N *&?

Addition o

the /iller

nd o

$ncorporation

$ncorporation Ti#e increases 6ith

( the /iller Loading

( the -)Inu#ber

g

Ra# Setting3 $nluence o /iller Type


55/72

, + 9 %&

/iller J1ol.>L

9,

?,

+,

&,

,

Ra#

Se

tting

Ti#eJsL%,,

C)

CNT

N)R

HN)R

, + 9 %&

/iller J1ol.>L

9,

?,

+,

&,

,

Ra#

Se

tting

Ti#eJsL%,,

C)

CNT

N)R

HN)R

Ra# Setting3 $nluence o /iller Type

C) 5s CNT

C) needs long incorporation ti#e

Caused by the high structure or

4A Nu#ber

CNTs do not ha5e structure

$ncorporation ti#e is reduced to

%!* co#pared to C)

0o6er Consu#ption P Te#perature


56/72

Mixing ti#e t

MixingTe#p

erature

sp

ec.0o6erConsu#ption

Mixing ti#e t

The second po6er peaD is #ore pronounced 6henthe iller loading increases

The #ixing te#perature increases 6ith loading

The 5iscosity decreases 6ith te#perature o the #ix

p p

nergy $nput3 $nluence o /iller Type


57/72

+ 9 %&/iller J1ol.>

&

*

+

:

?

ner

gy$nputJM

'L

C)

CNTN)R

HN)R

, + 9 %&/iller J1ol.>

&

*

+

:

?

ner

gy$nputJM

'L

C)

CNTN)R

HN)R

C) 5s CNT

nergy input is #uch higher or

CNT co#pounds than or

C) co#pounds

The eect is caused by the increase o

1iscosity in CNT co#pounds.

A li#it or processability is reached or

CNT co#pounds

Mixer nergy()alance


58/72

compound enthalpy

or coolin!

mechanical

mixer enthalpy

15% 10%

30%

45%

Typical exa#pleB

$nluence o oil incorporation


59/72

$ the 4il addition is delayed.

()etter dispersion

(Ti#e should be chosen

$ the 4il addition is strongly delayed.

(Lubrication il#s i#pair the dispersion

(energy uptaDe is s#all

(Long #ixing ti#e

$ the 4il and C) are added at the sa#e ti#e

(4il is incorporated FuicDly

(Maxi#u# torFue is relati5ely s#all

Strategies or 4il -osage


60/72

Lecture04A%%.,?.&,,=?,

High a#ount o oilMixing ti#e is 5ery long

Mixer reFuires long ti#e

to reco5er torFue

Auto#atic inter#itent4il inOection

nergy uptaDe

Shorter #ixing cycle

Scaling(Up


61/72

g

$#portant Step or 0roductionReFuire#ents

"eo#etrical Si#ilarity

sa#e clearance bet6een rotor and#ixing cha#ber

/reFuency o the rotors should be in5ersely

proportional to the 6idth o their tips

increase the initial te#perature and reduce

cooling o the s#aller #ixer

identical shear strain and shear stress po6er!unit 5olu#e

(

(

(

sa#e reFuency o passage o any s#all ele#ent

through #ixing regions

(


62/72

Ho6 to increase producti5ity and Fuality

-esign o the #ixing process Mixing eecti5ity

Target Conlict3 uality(Throughput


63/72

Wiedmann & Schmidt RCT 1984

"uality

Th

rou!hput

/ill actor or opti#al iller dispersion3

( $ncreases 6ith ra# pressure and te#perature

( -ecreases 6ith rotor speed and te#perature

Design of the mixing Process:


64/72

: Bales are cut

: Crumby structure

: Homogeneous Blenda: Ram down

b: (minimum)

c: Ram at lowest position

d: Maximum density

e: CB incorporation com-

pleted

Effect of Mastication CB !ncorporation

g g

Mixer: "#$%E

Rotor: &E'- fixed speed


0

o6erD7!h

Ti#e sB

Experimental esign


65/72

lo6 high

/ill actor ,.:9 ,.?*

Rotor speed rp#B +, ?,

)lending ti#e sB *, ?,-ispersion ti#e sB +& ?,

#esults

/Rb- /R)-)lend appearance cru#by ho#ogeneous

-u#p te#perature %?, %?&C

Cycle ti#e %9, %9& s

C) incorporation loose blacD co#pleted

Mixer: "#$%E

Rotor: &E'- fixed speed". NiO#anG -$@ Se#inar &,,=

*ingerprints


66/72

*Rb *RB


Mixer: "#$%ERotor: &E'- fixed speed

0

o6erD7!h

0

o6erD7!h

Ti#e sB Ti#e sB

$nluences on Co#pound 0roperties


67/72

Fuip#ent

"eo#etry

MaintenanceCooling

Control

Sensors

0rocess

-iscontinuous

ContinuousTande#

/eeding SeFuen

-uration o

Mixing 0hases

$nluences on Co#pound 0roperties

uality

Material

0oly#er

/iller0lastici2er

Additi5es

Curing syste#

Hu#an

ducation

ualiication

Moti5ation

-osage

7eighing tolerance

Calibration

)atch to batch 5ariation in /ingerprints


68/72

A 5ariation in #ixing Fuality could lead to


69/72

too hea5y co#ponents

too #uch #aterial i. e. ,.: Dg in one 0CR tyreB

a huge a#ount o re6orD

o5er di#ensioned co#pound recipes and thereore a rather ineicient production

&G9

&G8

*

*G%

*G&

*G*

*G+

*G:

% & * + : ? = 9 8 %,

$ample

Dimension

7hat can be #easured on(line

to control the #ixing process V


70/72

to control the #ixing process V

Ra# -isplace#ent

Ra# 0ressure

Mixing Cha#ber

Te#perature

Rotor Speed 0o6er

4n(line lectrical Measure#ents


71/72

ring electrodeRa#

0icoa#pere#eter

A#pliier

Rotor 6ing

l. Source

lectrode

Cha#ber 6all

)eneits and -isad5antages o


72/72

Lecture04A%%.,?.&,,==&

)eneits

Accepts al#ost any

trade or# 0ro5en technology

No need or specialdosing eFuip#ent

)oth auto#atic and#anual control

icient dispersioneect

/lexibility in run length

easyW to #aintain androbust #achine

7ide application ield

-isad5antages

High po6er peaDs

)atch to batch 5ariationI heat history

I #aterial 6eight 5ariation

-ust or#ing by air

#o5e#ent Labour intensi5e

Many adOustablepara#eters

High installation costs

Co#plicateddo6nstrea#

)atch Mixers

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