Advanced compounding strategies to avoid injection ... · Injection Moulding • High precision components – Seals, O rings, – Gaskets and bellows, ... Struktol Zimag 29/43 8

©Schill + Seilacher “Struktol” A.G. 2006

S o l u t i o n s . T a i l o r m a d e . W o r l d w i d e

Advanced compounding Advanced compounding strategies to avoid injection strategies to avoid injection

moulding pitfallsmoulding pitfalls

A presentation for VKRT A presentation for VKRT conference 7conference 7--1212--20062006


ContentsContents

•• The Injection Moulding ProcessThe Injection Moulding ProcessCompounds and requirementsCompounds and requirements

•• The AdditivesThe AdditivesChoosing better process additivesChoosing better process additives

•• The Benefits availableThe Benefits available


Injection MouldingInjection Moulding

•• Suited for high Suited for high numbers of partsnumbers of parts–– Multiple mould cavities Multiple mould cavities

are commonare common–– Good flow properties Good flow properties

are requiredare required



•• High precision High precision componentscomponents–– Seals, O rings, Seals, O rings, –– Gaskets and bellows,Gaskets and bellows,–– Metal bonded partsMetal bonded parts–– Rubber compounds Rubber compounds

must be well mixedmust be well mixed



•• Highly automated Highly automated processprocess–– Short production Short production

cycles are usedcycles are used–– Robotised demouldingRobotised demoulding–– High uniformity of High uniformity of

produced partsproduced parts


Injection Moulding Compounds Injection Moulding Compounds

Key RequirementsKey RequirementsMust have Must have high level of dispersionhigh level of dispersionNeed to have Need to have good flow propertiesgood flow propertiesA A fast cure ratefast cure rate is requiredis requiredMust Must release easilyrelease easily from the mouldfrom the mouldShould be Should be low in mould foulinglow in mould fouling


Process Additives for Injection MouldingProcess Additives for Injection Moulding

•• Fatty acidsFatty acids•• Functional fatty acids Functional fatty acids –– metal soapsmetal soaps•• SiliconesSilicones•• OrganosiliconesOrganosilicones

Many types of materials are offered to improve all aspects of mixing and especially flow properties

It is important that the additives do not adversely affect compound quality. An understanding of their action is needed

Are all widely used as lubricants or release agents for injection moulding


Requirements of Process AdditivesRequirements of Process Additives

To improve flow and release To improve flow and release during high during high shear processingshear processing

Best effectBest effect is obtained when the is obtained when the process process additive is added later in the mixing cycleadditive is added later in the mixing cycle

?? However the However the process additive process additive must also bemust also be well well dispersed in the compounddispersed in the compound

With With low temperaturelow temperature and low shear mixing of and low shear mixing of soft compounds this soft compounds this may be a concernmay be a concern


Measuring Flow PropertiesMeasuring Flow Properties

0

0.2

0.4

0.6

0.8

1

0.1 1 10 100 1000 10000Shear rate (sec-1)

Visc

osity

(ind

ex)

Mooney Viscosity

MixingExtruder Calendar

Capillary Rheometer

RPA

Transfer &InjectionMoulding

Control –

Process additive #1 –

Process additive #2 --


Relevant Testing is RequiredRelevant Testing is Required

Mooney ViscosityMooney ViscosityOnly as a simple ranking or for basic QCOnly as a simple ranking or for basic QCFixed shear rateFixed shear rate

Rubber Process AnalyserRubber Process AnalyserMore useful as shear rate can be variedMore useful as shear rate can be varied

Capillary RheometerCapillary RheometerEffective over wide shear rateEffective over wide shear rateTime consuming testTime consuming test

Injection Moulding TrialInjection Moulding TrialGives direct indication of performanceGives direct indication of performance

Schill + Seilacher can make all the above tests!Can your supplier do the same?


Struktol WB 16 an Additive for Injection MouldingStruktol WB 16 an Additive for Injection Moulding

WB 16 is widely used as a lubricant for WB 16 is widely used as a lubricant for improved flow and release properties.improved flow and release properties.

It is high in polarity and is surface actingIt is high in polarity and is surface acting

It is very effective in synthetic polymersIt is very effective in synthetic polymers

It is highly crystalline and has a sharp It is highly crystalline and has a sharp melting point (ca 102melting point (ca 102 °°C)C)

For best effect WB 16 should be added towards the end of mixing


Process Additive DispersibilityProcess Additive Dispersibility

Poorly dispersed aggregate of a

process additive material found in a

low viscosity compound

Poorly dispersed aggregate of a

process additive material found in a

low viscosity compound


Struktol HT ProductsStruktol HT Products

A new range of products developed to offer A new range of products developed to offer added advantagesadded advantages

Several products have Several products have improved dispersing natureimproved dispersing nature

Easier dispersibility at lower temperaturesEasier dispersibility at lower temperatures

Can be mixed intoCan be mixed into soft compounds soft compounds or ator at end of mixingend of mixing

HT ProductHT Product Standard ProductStandard ProductHT 202HT 202 A 50PA 50PHT 204HT 204 WB 16WB 16HT 266HT 266 EF 44EF 44HT 503HT 503 Aktivator 73Aktivator 73--AA


Better / faster dispersion of HT variant compared to standard

process additive grades

Better / faster dispersion of HT Better / faster dispersion of HT variant compared to standard variant compared to standard

process additive gradesprocess additive grades

HT Product offers improved safety for use in

soft compounds or low viscosity compounds when added at the end of mixing

or in mill mixing.

HT product will disperse at temperatures above 60°C

HT Product offers HT Product offers improved safety for use in improved safety for use in

soft compounds or low soft compounds or low viscosity compounds when viscosity compounds when added at the end of mixing added at the end of mixing

or in mill mixing.or in mill mixing.

HT product will disperse at HT product will disperse at temperatures above 60temperatures above 60°°CC

ResultImproved flexibility

Improved safetyImproved performance

ResultResultImproved flexibilityImproved flexibility

Improved safetyImproved safetyImproved performanceImproved performance


IngredientIngredient ControlControl WB 16 FlWB 16 Fl WB 16WB 16 HT 204HT 204

CR (Type W)CR (Type W) 100100 100100 100100 100100ODPAODPA 22 22 22 22AFDAFD 11 11 11 11NN--990990 3535 3535 3535 3535Struktol KW 400Struktol KW 400 3030 3030 3030 3030Struktol Zimag 29/43Struktol Zimag 29/43 88 88 88 88Struktol WB 16 FlakeStruktol WB 16 Flake 33

Struktol WB 16 MicrobeadStruktol WB 16 Microbead 33

Struktol HT 204Struktol HT 204 33

DOTGDOTG 11 11 11 11

CBSCBS 11 11 11 11

SulphurSulphur 0.50.5 0.50.5 0.50.5 0.50.5

Single stage mixing in laboratory Banbury. Process additives added late after 2’ 45’’ – together with curativesDump at 3’ 30”


MDR 2000180 °C

0

1

2

3

4

5

6

7

0 5 10 15 20 25 30

time (min)

torq

ue (d

Nm

)

0

1

2

3

4

5

6

7

0 60 120 180time ( sec )

power (kW)

Control – WB 16 Fl – WB 16 – HT 204 --

Mixing energy is reduced due to presence of WB 16 types.

Rotor slippage occurs due to insufficient WB 16 dispersion.

Low temperature generation

Mixing energy is reduced due to presence of WB 16 types.

Rotor slippage occurs due to insufficient WB 16 dispersion.

Low temperature generation

Cure curves show reduced max torque with WB 16 variants.

Probably this is due to rotor slippage as undispersed WB 16

melts at 180°C during curing

Cure curves show reduced max torque with WB 16 variants.

Probably this is due to rotor slippage as undispersed WB 16

melts at 180°C during curing


Control WB 16 Microbead

WB 16 Flake HT 204 (Microbead)

Microscope images of cut surfaces of vulcanisates


Tensile StrengthTensile Strength

0

2

4

6

8

10

12

14

MPa

Control WB 16 Flake WB 16Microbead

HT 204


ConclusionConclusion

In a soft / low temperature mixing In a soft / low temperature mixing compound for injection mouldingcompound for injection moulding

Struktol WB 16 flake did not disperseStruktol WB 16 flake did not disperse

Struktol WB 16 microbead was borderlineStruktol WB 16 microbead was borderline

Struktol HT 204 was fully OKStruktol HT 204 was fully OK


Evaluate the Point Of AdditionEvaluate the Point Of Addition

Is better performance obtained ?Is better performance obtained ?

•• Late addition Late addition avoids process additiveavoids process additivebecoming becoming bound to active filler surfacebound to active filler surface

•• Increased Increased process additive mobilityprocess additive mobility will will result in result in improved flow and releaseimproved flow and release

•• Process additive Process additive must disperse OKmust disperse OK


IngredientIngredient ControlControl HT 204 earlyHT 204 early HT 204 lateHT 204 late

Silica (VN3)Silica (VN3) 1010 1010 1010

CR (Type W)CR (Type W) 100100 100100 100100ODPAODPA 22 22 22AFDAFD 11 11 11NN--220220 3030 3030 3030

Struktol KW 400Struktol KW 400 1010 1010 1010Struktol Zimag 29/43Struktol Zimag 29/43 88 88 88Struktol HT 204 (added early)Struktol HT 204 (added early) 33

Struktol HT 204 (added late)Struktol HT 204 (added late) 33

DOTGDOTG 11 11 11

CBSCBS 11 11 11

SulphurSulphur 0.50.5 0.50.5 0.50.5

Single stage mixing in laboratory Banbury. HT 204 added early after 30 seconds – together with silicaHT 204 added late after 2’ 30” - together with curativesDump at 3’ 30”


Injection Mould Flow TrialsInjection Mould Flow Trials

•• Use a Use a ““Spider MouldSpider Mould””–– Uninterrupted mould flowUninterrupted mould flow

•• Measure each Measure each moulding weightmoulding weight–– Plot for each compoundPlot for each compound


Injection Mould Flow AnalysisInjection Mould Flow Analysis

26

28

30

32

34

0 5 10 15 20 25 30 35

Mould cycle

mou

ldin

g w

eigh

t (g)

Struktol HT 204 added late Struktol HT 204 added early Control


Spider MouldingsSpider Mouldings

ControlControl Struktol HT 204 Struktol HT 204 added earlyadded early

Struktol HT 204 Struktol HT 204 added lateadded late


ConclusionConclusion

The point of addition has an influenceThe point of addition has an influence

Late additionLate addition resulted in resulted in increased increased flow propertiesflow properties for the same loadingfor the same loading

Struktol HT 204 dispersed OKStruktol HT 204 dispersed OK when when added late in mixingadded late in mixing


Evaluate Mould FoulingEvaluate Mould Fouling

Injection moulding is a high volume process for Injection moulding is a high volume process for production of precision components. Down production of precision components. Down time due to mould fouling must be minimisedtime due to mould fouling must be minimised

Evaluate the influence of process Evaluate the influence of process additives on degree of mould foulingadditives on degree of mould fouling


Reduced Injection Mould FoulingReduced Injection Mould Fouling

IngredientIngredient ControlControl CompetitorCompetitor Struktol HT 282Struktol HT 282

Vulkanox HS/LGVulkanox HS/LG 11 11 11

Vistalon 3666Vistalon 3666 175175 175175 175175NN--550550 9595 9595 9595Paraffinic OilParaffinic Oil 1010 1010 1010ZnOZnO 1010 1010 1010

Vulkanox MB2/MGVulkanox MB2/MG--CC 11 11 11Competitor productCompetitor product 44

Struktol HT 282Struktol HT 282 44

Perkadox 14Perkadox 14--4040 88 88 88

Sartomer 206Sartomer 206 2.52.5 2.52.5 2.52.5

Peroxide cured EPDM with co-agent is highly mould foulingStruktol HT 282 is a silicone based lubricant / release agentA competitive product offered for injection moulding is included


Injection Mould Flow AnalysisInjection Mould Flow Analysis

22

23

24

25

26

Mould cycle

mou

ldin

g w

eigh

t (g)

Control Competitor additive Struktol HT 282


Spider MouldingsSpider Mouldings

ControlControl Competitor additiveCompetitor additive Struktol HT 282Struktol HT 282


MouldMould Fouling RatingFouling Rating SystemSystem

Use Mould cleaningcompound Struktol MC-I

Use Mould cleaningcompound Struktol MC-I

Dirty mould after 30 injection cyclesDirty mould after 30 injection cycles AreasAreas A A –– E E areare ratedrated regardingregardingExtentExtent of of MouldMould FoulingFouling bestbest to to

worstworst = 1 to 6 = 1 to 6 ((frontfront-- and and backsidebackside))

ED

C B B C

A


Mould Cleaning Compound TrialsMould Cleaning Compound Trials

Struktol HT 282Struktol HT 282

Rating = 6Rating = 6

ControlControl


Competitor additiveCompetitor additive


Cleaning compound used to remove mould fouling deposited following 30 injection mouldings with each compound

Cleaning compound used to remove mould fouling deposited following 30 injection mouldings with each compound


ConclusionsConclusions

Process additives for injection mouldingProcess additives for injection mouldingMust be selected with careMust be selected with careThe point of addition is an important factorThe point of addition is an important factorConsider additive dispersibilityConsider additive dispersibilityMicrobead products safer than pelletisedMicrobead products safer than pelletised

Struktol HT products are safer in all compoundsStruktol HT products are safer in all compoundsAre more efficient when added later in mixingAre more efficient when added later in mixingCan contribute towards reduced mould foulingCan contribute towards reduced mould fouling


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

Distributed in this region by:

C.N. Schmidt B.V.

www.cnschmidt.nl

Distributed in this region by:Distributed in this region by:

C.N. Schmidt B.V.C.N. Schmidt B.V.

www.cnschmidt.nlwww.cnschmidt.nl

Documents

Advanced compounding strategies to avoid injection ... · Injection Moulding • High precision components – Seals, O rings, – Gaskets and bellows, ... Struktol Zimag 29/43 8