injection molding of rubber

7/30/2019 injection molding of rubber

1/39

Belgian Plastics and Rubber

InstituteAdditives and Processing Aids

forPolymersConference in cooperation with BPG

Oktober 22th 2008, Auberge du Pecheur ,

Sint Martens-Latem (Gent)


2/39

StruktolStruktol ProcessProcess AdditivesAdditives

InjectionInjection MouldingMoulding ofofrubberrubbercompoundscompounds

ImprovmentsImprovmentsbyby usingusing additivesadditives

PROCESSING AIDS FOR POLYMERSPROCESSING AIDS FOR POLYMERS

Schill + SeilacherSchill + Seilacher StruktolStruktol AktiengesellschaftAktiengesellschaftPeter Kosczinsky 644


3/39

3

Contents

1. Production Processes Compounds and Requirements

2. Processing Additives Introduction + Function

3. How to choose the right Process Additive4. Example Case Studies problems and their solution

5. Conclusion


4/39

4

Injection Moulding Compounds

Requirements

Must have high level of dispersion

Need to have excellent flow properties

A fast cure rate is required

Must release easily from the mould

Should be low in mould fouling


5/39

5

Injection Moulding

High precision

components

Seals, O rings,

Gaskets and bellows,

Metal bonded parts

Rubber compounds

must be well mixed


6/39

6

Injection Moulding

Highly automated

process

Short production cycles

are used

Robotised demoulding

High uniformity of

produced parts


7/39

7

2. Production Process in the Rubber Industry

What can be influenced by process addit ives?

Raw

Materials RubberCompound

Finalrubber

article

CompoundingCompounding ProcessingProcessing


8/398

2.1 Function of ProcessAdditives

Compounding stage

Raw

MaterialsRubber

CompoundFinal

rubber

article


Viscosity reduction

Easier mixing release

Better batch homogenity

Shorter cycles, more

efficient mixing

Better fil ler dispersion

F t P


9/399

Raw

MaterialsRubber

CompoundFinal

rubberarticle


. Functon o ProcessAdditives

Processing stage

Improved compound flow

Reduced compound st ickiness

Better demoulding / Less foul ing

Improved article appearance

Higher productivity

L t


10/3910

3. The Choice of Additive

Problem?!

Suited, most efficient

process additive is

choosen

Know-How

Experience

Type of polymerused / blend ?

Formulation analysis:filler dosage?

curingsystem?plasticiser type?

stearic acid level?etc.

Appearance ofrubber part ?

Whatproductionprocess ?

Problem Details?

Other details:Mooney viscosity,ShA, rubber-metal

bonding, automotive?etc


11/3911

4. Example Case Studies

4.1 Injection Moulding of EPDM

Formulation : 3907.5 Compound 1 Compound 2

Vistalon 3666 175 175

N-550 Statex 95 95

Sunpar 2280 10 10

ZnO 10 10

Vulkanox HS/LG 1 1

Vulkanox MB2/MG-C 1 1

Struktol WS 180 (flakes) 2

Perkadox 14-40 8 8

Sartomer 206 2,5 2,5

Sum : 302,5 304,5

Occuring Problems:

a) insufficient compound flow

b) stickiness of parts to mouldsurface

c) quick mould foul ing

Process Additive

Struktol WS 180

- Process lubricant(organosilicone based)

- efficient at lowdosage 0,5 - 2 phr

- well compatiblewith EPDM

(lowperoxide demand)

- pelletised product

- suited forautomotivesector


12/3912

4.1 Injection moulding of EPDM(Compound1 + Compound 2)

a) Influence of compound flowTrial procedure

Injection Spider MouldArburg Injection Machine

Compound 1 (control) andCompound 2 (Struktol WS 180)

injected 30 cycles


13/3913


a) Influence of compound flowThe Result

Compound 1:Control spider

Compound 2:Spider incl. Struktol WS 180


14/3914


c) Reduction of mould fouling levelTrial Procedure

Compound 1 + Compound 2:injected 30 cycles each

Mould cleaning: Struktol MC-Imould cleaning compound

injected after Compound 1 andCompound 2 cycles


15/3915


c) Reduction of mould fouling levelA Rating Scheme how to judge dirt level in the mould

Areas A E arerated with notes

(front- and backside):

Dirt Level Note


16/3916


c) Reduction of mould fouling levelThe Result

DirtLevel caused byCompound 1 (control)

DirtLevel caused byCompound 2 (Struktol WS

180)

Note: 6Note: 8


17/3917

5. Example Case Studies

5.2 Injection of AEM (Vamac)Mischung 3828.4 Compound 1 Compound 2Vamac HGV 50 50

Vamac G 50 50Russ N-772 70 70

Struktol KW 759 5 5Naugard 445 2 2

Armeen 18D 0,5 0,5

Stearinsure 2Struktol WB 222 2

Vulcofac HDC 1,25 1,25Ekaland DPG 4 4

Summe 184,75 184,25

Occuring Problems:

a) insufficient compound flow

b) stickiness of parts to mouldsurface

c) mould fouling

Process Additive

Struktol WB 222

Process lubricant

(fattyacid / esterbased)

- Dosage 11,0 - 3,0 phr

- well compatible withAEM

- Mikro Beads

- suited for automotivesector


18/3918

5.1 Injection moulding of AEM(Compound 1 + Compound 2)

a) Influence of compound flow

The Result

Compound 1

Armeen 18D +

Stearic Acid

Mischung 2

Armeen 18D +

WB 222


19/3919

Compound 1 + Compound 2

Injection with 40 cycles each

Mould cleaning: Struktol MC-I

mould cleaning compoundinjected after compound 1 +

compound 2 cycles

Trial procedure


a) Influence of mould fouling


20/3920


a) Influence of mould fouling

The result

Dirt level caused by

compound 1 - control

(Armeen 18D + Stearic Acid)

Dirt level caused by

Compound 2

(Armeen 18D + WB 222)


21/3921

Semi-permanent Release AgentsStruktol Permalease 90

Instant curing

Can be used at low mould temperatures(130C)

Water based Reduction of mould fouling

Good surface finish


22/3922

MouldMould SurfaceSurface ModificationModification

AFM microscope view of coated steel plate in frictionAFM microscope view of coated steel plate in friction

modemode

Permalease

coated

uncoated

Friction Modus


23/3923

Influence of mould fouling(Injection moulding of AEM compounds)

Compound1 + Compound 2

Trial procedure

Spider Mould Arburg Injectionmoulding Mould coating with Struktol

Permalease 90


24/39

24

Influence of mould foulingResult: Injection moulding of AEM

coated + uncoated mould.

Dirt level after 40 cycles

with a uncoated mould

Dirt level after 40 cycles

with a coated mould

Compound 1 (Armeen 18D / Stearinsure)


25/39

25

Influence of mould foulingResult: Injection moulding of AEM

coated + uncoated mould

Dirt level after 40 cycleswith a uncoated mould

Dirt level after 40 cycleswith Permalease 90

coated mould

Compound 2 (Armeen 18D / WB222)


26/39

26

5. Conclusion

It is important to choose the best suitedprocess additive for concerned process /occured problem

UseUse ofoflittlelittle processprocess additiveadditive helpshelps toto solvesolve

productionproduction problemsproblems in anin an easyeasy wayway

InjectionInjection mouldingmoulding problemsproblems cancan bebe resolvedresolved byby

usingusing e.ge.g.. StruktolStruktol WS 180WS 180 oror StruktolStruktol WB 222WB 222 ((betterbetter

flowflow,, lowerlower mouldmould foulingfouling,, improvedimproved articlearticle appearanceappearance))


27/39

27

Struktol HT Products

A new range of products developed to offeraddedadvantages

Several products have improved dispersing nature

Easier dispersibility at lower temperatures Can be mixed into soft compounds or at end of mixing

EF 44HT 266

A86HT 105

WB 16HT 204

A 50PHT 202

Standard ProductHT Product


28/39

28

Better / faster dispersion of HTvariant compared to standard

process additive grades

Better / faster dispersion of HTBetter / faster dispersion of HT

variant compared to standardvariant compared to standard

process additive gradesprocess additive grades

HT Product offers

improved safety for use insoft compounds or low

viscosity compounds whenadded at the end of mixing

or in mill mixing.

HT product will disperse at

temperatures above 60C

HT Product offersHT Product offers

improved safety for use inimproved safety for use insoft compounds or lowsoft compounds or low

viscosity compounds whenviscosity compounds when

added at the end of mixingadded at the end of mixing

or in mill mixing.or in mill mixing.

HT product will disperse atHT product will disperse at

temperatures above 60temperatures above 60CC

ResultImproved flexibility

Improved safety

Improved performance

ResultResultImproved flexibilityImproved flexibility

Improved safetyImproved safety

Improved performanceImproved performance


29/39

29

HT 204WB 16

BeadsWB 16 FlControlIngredient

0.50.50.50.5Sulphur

1111CBS

1111DOTG

3Struktol HT 204

3Struktol WB 16 Microb.

3Struktol WB 16 Flake8888Struktol Zimag 29/43

30303030Struktol KW 400

35353535N-990

1111AFD

2222ODPA

100100100100CR (Type W)

Single stage mixing in laboratory Banbury.

Process additives added late after 245 together withcuratives

Dump at 3 30


30/39

30

MDR 2000

180 C

0

1

2

3

4

5

6

7

0 5 10 15 20 25 30

time (min)

torque(d

Nm)

0

1

2

3

4

5

6

7

0 60 120 180

time ( sec )

power (kW)

Control WB 16 Fl WB 16 HT 204 --

Mixing energy is reduced due topresence of WB 16 types.

Rotor slippage occurs due toinsufficient WB 16 dispersion.

Low temperature generation

Mixing energy is reduced due topresence of WB 16 types.

Rotor slippage occurs due toinsufficient WB 16 dispersion.

Low temperature generation

Cure curves show reduced maxtorque with WB 16 variants.

Probably this is due to rotorslippage as undispersed WB 16

melts at 180C during curing

Cure curves show reduced maxtorque with WB 16 variants.

Probably this is due to rotorslippage as undispersed WB 16

melts at 180C during curing


31/39

31

Rheological behaviour:

0,030,040,040,03tan delta (MH)

7,888,97,6tc 90%

1,31,41,41,3tc 10%

65,55,56,1torque MH (d/N/m)

0,20,20,20,2torque ML (d/Nm)

180C/30180C/30180C/30180/30Rheometer MDR 2000

1210713Mooney viscosity (1+4)

65555673Sample temperature (C)

408339339478energy consumption (kj)

53515359dump temperature (C)

HT 204WB 16

Beads

WB 16 FlControl


32/39

32

Physical properties:

2,22,32,52,2Modulus 300% (MPa)

0,60,60,60,6Modulus 100 % (MPa)

745669588759elongation at break (%)

12,310,57,312,7tensile strength (MPa)

Tensile test

31313131Shore hardness

30303030cure time for 6 mm (min) 180C

30303030Cure time for 2 mm (min) 180C

HT 204WB 16

Beads

WB 16 FlControl


33/39

33

Control WB 16 Microbead

WB16 Flakes HT 204(Microbead)

Microscope images of cut surfaces of vulcanisates


34/39

34

Tensile Strength

0

2

4

6

8

10

12

14

M Pa

C ontrol WB 16 Flake WB 16

M icrobead

HT 204


35/39

35

Conclusion

In a soft / low temperature mixing

compound for injection moulding

Struktol WB 16 flake did not disperse

Struktol WB 16 microbead was borderline

Struktol HT 204 was fully OK


36/39

36

101010Silica (VN3)

HT 204 lateHT 204 earlyControlIngredient

0.50.50.5Sulphur

111CBS

111DOTG

3Struktol HT 204 (added late)

3Struktol HT 204 (added early)

888Struktol Zimag 29/43

101010Struktol KW 400

303030N-220

111AFD

222ODPA

100100100CR (Type W)

Single stage mixing in laboratory Banbury.

HT 204 added early after 30 seconds together with silica

HT 204 added late after 230- together with curatives

Dump at 3 30


37/39

37

Spider Mouldings

ControlControl Struktol HTStruktol HT

204 added204 addedearlyearly

Struktol HTStruktol HT

204 added late204 added late


38/39

38

Conclusion

The point of addition has an influence

Late addition resulted in increased flowproperties for the same loading

Struktol HT 204 dispersed OKwhenadded late in mixing


39/39

Thank you for your attentionThank you for your attentionThank you for your attention

For more info: www.struktol.deFor more info: www.struktol.deFor more info: www.struktol.de
http://www.struktol.de/http://www.struktol.de/http://www.struktol.de/http://www.struktol.de/http://www.struktol.de/http://www.struktol.de/

Documents

injection molding of rubber