akulon en brochure - ferromet · toughness, fatigue and wear properties 25 water absorption and...
TRANSCRIPT
General information
on applications, processing
and properties
Akulon
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Contents
Introduction 4
Automotive applications 6
Akulon in E&E applications 8
Other injection mouldingapplications 11
Extrusion applications 12Film 12Semi-finished materials 12Convoluted tubes 13
Designing with polyamides 14Dimensions 14Surface appearance 15Wall thickness 15Corners and radii 15Ribbing 15Assembly 15
Injection moulding of Polyamides 16Machinery 16Material handling 16
Characteristic properties of Akulon 18Positioning Akulon in the world ofThermoplastics 18Temperature performance 18Toughness, fatigue and wear properties 25Water Absorption and HydrolysisResistance 26Chemical Resistance 27Electrical Properties, Flammability andUL Classifications 27Aftertreatments 28Polyamides versus Polyesters 29Polyamide 6 versus Polyamide 66 29
DSM EP product portfolio 30
Typical data 31
Contact information 32
DSM
DSM is active worldwide in life scienceproducts, performance materials andindustrial chemicals. The group hasannual sales of close to EUR 5.6 billionand employs about 18,500 people atmore than 200 sites across the world.DSM ranks among the global leaders inmany of its fields. The company’sstrategic aim is to grow its sales - partlythrough acquisitions - to a level ofapprox. EUR 10 billion by 2005. By thattime at least 80% of sales should begenerated by specialties, i.e. advancedchemical and biotechnical products forthe life science industry andperformance materials. This strategyrepresents a continuation of thecompany’s ongoing transformation andconcentration on global leadershippositions in high-added-value activitiescharacterized by high growth and morestable profit levels.
DSM Engineering Plastics is aBusiness Group in the performancematerials cluster of DSM, with sales in2002 of EUR 579 million and 1300employees worldwide. It is one of theworld’s leading players in the field ofengineering thermoplastics offering abroad portfolio of high performingproducts.
DSM Engineering Plastics operates in allmajor markets of the world including theAmericas, Asia, and Europe. Within eachregion customers can count on ourinnovative research, development, andsupport facilities. Our in-house resourcesare backed by a corporate research anddevelopment center that is utilized increating new solutions for customerneeds. The advanced level of accountmanagement, in combination with oureffective global communication networksecures the support customers needwherever it is required.
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With polymerization and compoundingfacilities for a range of polyamides,polyesters and polycarbonates, we serveour global customers base and assure aconstant, reliable supply of products.
Recently, DSM completed majorinvestments in the building of Akulonpolyamide 6 polymerization plants bothin the USA and in the Netherlands, aswell as finalizing a joint venture withXinhui in China for the production ofpolyamide 6 polymer. The capacity ofthe polymerization plant for Stanylpolyamide 46 in the Netherlands wasincreased by 30% to meet the highgrowth demand for this product.Access to polycarbonate was securedunder a long term capacity sharingagreement with Dow Chemical.
All our compounding facilities in theworld (in the Netherlands, Belgium, USA,Canada, China and India) are beingexpanded continuously to keep up withthe growing demand.
As a result of a constant productinnovation and creation process, DSMEngineering Plastics can offer a cohesiveportfolio of high performing engineeringplastics. Established trade names are:Akulon® (PA6 and PA66)Akulon® Ultraflow™(high flow Akulon PA6)Akulon® XP(Xtreme Performance PA6 for film)Arnite® (PBT, PET)Arnitel® (TPE-E)Stamylan® UH (UHMWPE)Stanyl® PA46 (PA46)Stanyl PA46 High Flow™(high flow PA46)Stapron® (PC-blends)Xantar® (PC)Yparex® (extrudable adhesive resins)
Complemented in some regions byproducts as:Electrafil® (conductive products)Fiberfil® (reinforced polypropylene)Nylatron® (PA66 specialties)Plaslube® (lubricated products)
These materials all have their specificproperties, yet they share the same highquality, thanks to state-of-the-artproduction processes and qualitysystems, like Total Quality Management,ISO 9001 and QS 9000.It’s an approach to quality that can befound throughout the DSM organization:- in relations with industry partners,
working closely together in true co-makership, ready to meet anytechnical challenge
- in technical service and after sales,providing support to help customersoptimize their processes
- in logistics and delivery, shippingproducts anywhere in the world,quickly and reliably.
From product concept, throughprocessing, to final application DSMEngineering Plastics brings the portfolio,the skills and the global presence to helpits industrial partners create world-classproducts and solutions.
It’s surprising what we can dotogether!
Production sites
EuropeEmmen - Netherlands (polymerizationand compounding)Geleen - Netherlands (polymerization)Genk - Belgium (compounding)Stade - Germany (polymerization)
North AmericaEvansville - Indiana (compounding)Augusta - Georgia (polymerization)Stoney Creek - Ontario Canada(compounding)
Asia PacificJiangsu - China (compounding)Pune - India (compounding)Tokyo - Japan (M/S joint venture and tollcompounding)
Introduction
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DSM has been involved in polyamidesalmost from its beginning. The companyhas a long history as a supplier ofpolyamides and a provider of polyamideknow-how and technical service. DSMcontinues to invest in polymerization andcompounding plants and technology. Today, DSM is one of the largestmerchant caprolactam suppliers in theworld and one of the largest globalsuppliers of polyamide resins andcompounds.
The company’s caprolactam facilities arelocated close to its large PA6polymerization and compounding plantsin the US, Europe and Asia. DSM’sefforts to achieve full backwardintegration from monomer tocompounded resins underscores itscommitment to global engineeringplastic supply. In addition, itdemonstrates DSM’s focus on thecontinuing growth and quality ofpolyamides. DSM Engineering Plasticsmanufactures polyamide resins underthe trade name Akulon, its largestproduct line. The company’s vast expertise enables itto play a unique role as a resin producerand compounder.
New plant. In 2000 DSM EngineeringPlastics started up a new state-of-the-artPA6 polymerization plant in Emmen, theNetherlands. Downstream of thispolymerization unit is a largecompounding plant. Anotherpolymerization unit is located in Augusta(Georgia, US), with compoundingfacilities in Evansville (Indiana) andStoney Creek (Canada). In Japan, thegroup has formed a joint venture withJapan Synthetic Rubber Co., Ltd.(Tokyo), and in China it has a strongfoothold via a fully owned and stronglyexpanding compounding facility.
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New high-flow grades. Anotherrecent development is the introduction ofa new family of high flow grades withundiminished mechanical properties:Akulon Ultraflow. This product line offerstangible advantages such as stronglyimproved flow, shorter cycle times,better surface appearance and lesswear.
Polyamide 6 versus polyamide 66
Polyamide is the most commonengineering thermoplastic in use today.Annual consumption of polyamide forengineering plastic applications exceeds2000 ktons. Polyamides cover a broaderrange of applications than any otherengineering plastic. The Akulon gradesare suitable for all major processingtechniques, such as injection moulding,blow moulding and extrusion.
The most important application areas are- automotive: air and fuel ducts, under-
the-bonnet covers, door handles andtrunk grips, power train, blowmoulding and interior applications
- electrical/electronics: powerdistribution, industrial connectors,power tools and E&E components
- other industries: railway systems,furniture, castor wheels, sports goods,consumer durables, building productsand industrial goods.
Polyamide has an excellent combinationof properties:- high stiffness and strength at elevated
temperatures- toughness at low temperatures- excellent heat ageing resistance- good abrasion and wear resistance- chemical resistance- excellent surface appearance.
These properties can be enhanced bythe use of glass fibre and beads,minerals, flame retardants, tougheningagents and other additives.
Digital time switch components, Akulon K222-KGMV14.
Type Additive Remark GradeUnreinforced Low viscous F223-D
High viscous F130-B
Reinforced Glass fibres 30% GF K224-G630% GF, HS K224-HG635% GF, HS K224-HG7
Hybrid (glass 10% GF, 20% M, K223-HGM24fibres/minerals) HS
Flame retardant Glass fibres 20% GF, K222-KGV41)
halogen free
Hybrid (glass 5% GF, 20% M, K222-KGMV14fibres minerals) halogen free
The most important polyamide 6injection moulding grades in our portfolioare presented in Table 1 on this page.An overview of the available extrusiongrades can be found on page 13. You will find a more detailed overview ofour portfolio and the corresponding setof properties at the end of this brochure.The nomenclature is explained on page29, Table 13.
PA6 versus PA66. The Akulonproduct line encompasses a range ofpolyamide compounds based onpolyamide 6 and 66 types. However,given our backward integration, our coreproduct line is Akulon PA6. This fits in with our vision that in mostapplications polyamide 6 outperformspolyamide 66 at temperatures up to 185 °C, since PA6 yields in comparisonto PA66:
- higher toughness levels at lowtemperatures but comparablestiffness levels at elevatedtemperatures up to 185 °C
- better heat ageing resistance - easier processability (broader
processing window, the use of lowerprocessing temperatures can lead toshorter cycle times)
- higher weld strength after variouswelding processes;
- better surface appearance ofreinforced grades;
- the possibility of halogen-free flameretardancy in reinforced PA6 grades.
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Table 1. The most important PA6 grades in our portfolio.
1) K222-KGV4 and K222-KGMV14 are halogen free materials; HS = heat resistant.
These advantages can lead to lowersystem costs and/or better safetymargins in your applications. The highstiffness levels at elevated temperaturesand higher absolute values for strengthlevels measured after heat ageing, implysavings in material costs (because wallthickness can be reduced) or a highersafety margin (at a certain wallthickness). Also, the broader processingwindow and lower melting point ofpolyamide 6 mean easier processing. Processing costs can be reduced as aresult of lower energy costs and/orshorter cycle times. The highertoughness level leads to lower rejectlevels in production. The higher weldstrength of polyamide 6 provides bettersafety margins in the applications, whilstits superior surface appearance leads toan improved image in the marketplace.
More details can be found in thetechnical chapter in the second part ofthis brochure.
There are many reasons to chooseAkulon PA6 for your applications!
Ski-bindingsAkulon K224-TG9.
Automotive exterior
Door handles, radiator grilles. Asan integral part of tile vehicles body thedoor handles have many difficultrequirements. They must have anexcellent surface appearance, paintability and UV-resistance, but also goodmechanical properties, like stiffness andtoughness. DSM is one of the marketleaders in these applications and offers abroad portfolio of tailor made Akulonsolutions for door handles, for paintedand unpainted use. Akulon is easy toprocess, even in the most difficultprocesses for door handle applications,like gas assisted technology or foaming.
Automotive interior
Airbag containers. The task of anairbag is to save the head of a humanbeing from hitting a hard surface orcomponent in an automobile withinsome milliseconds. The materials toenable the airbag to do his job have tofulfil the most stringent specifications.They must carry specific mechanical andthermal properties and a certain productconsistency. The super toughenedAkulon K224-PG6 and K224-PG8 (PA6GF30 and GF40) withstand thesechallenging requirements. The polymerenables the system suppliers to designcost effective and state-of-the-art airbagcontainers.
Automotive applications
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DSM polyamides: first choice!
The demand for plastics of today’sautomotive industry is very simple buttough. Cost effective, innovativesolutions at benchmark quality,combined with global availability andrecyclability. Herefore, DSM’spolyamides and especially Akulon PA6 isthe first choice. With its unique propertyprofile Akulon PA6 can undoubtedly fulfilthe requirement of the automotiveindustry for its most challengingapplications, e.g. in the enginecompartment, for powertrainapplications, etcetera. And, when itcomes to recycling of End of LiveVehicles (ELV’s), DSM is developingways to chemically recycle ELV PA6parts. DSM Engineering Plastics is in theposition to offer post consumer PA6grades under the trade name AkulonRecap globally, partly coming from itsdepolymerization plant in Augusta.
Polyamides have been used for manyyears in the automotive industry. Due totheir performance profile, they can offerthe appropriate solution for manydifferent applications. Akulon polyamideshave been successfully applied in (seeTable 2):- automotive exterior;- automotive interior;- electrical and electronic applications;- under-the-bonnet.
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Door handles, Akulon K224-HG6. Airbag container, Akulon K224-PG8.
Exterior Interior Electrical Under the bonnetDoor handles Ski flaps Fuse boxes Air-/fuel modules
Tailgate handles Door openers Stork switches Airducts
Wheel trims Airbag housings Connectors Valve-/engine covers
Body panels Window winders Relay boxes Fans and shrouds
Radiator grilles Headrest support Sensors Gear box consoles
Table 2. Examples of automotive applications.
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Electrical and electronicapplications
Relay boxes. In automotive E&E-applications, Akulon PA6 plays animportant role when it comes to relayboxes. Akulon K224-HGR24 (PA6 GF10GB20) offers good mechanicalproperties and excellent weld linestrength at elevated temperatures,combined with the required dimensionalaccuracy. Where higher stiffnesscombined with excellent flowcharacteristics is demanded, Akulon K-FHGM44 (PA6 GF20 M20) can do thejob. That’s why many OEM’s rely onAkulon.
Under-the-bonnet
Air intake manifolds and airducts. ‘Fuel economy’ and ‘weightreduction’ are the main challenges of theautomotive OEM’s and their suppliers oftoday. A big step towards these goalscan be made by the integration offunctions and replacements of aluminiumand steel by plastics, e.g. for air intakecomponents.
Akulon PA6 play an important role in thisgame, be it a standard Akulon K224-HG6/HG7, a burst pressure/weldingoptimized Akulon K230-HXG6 or evenone of the blow moulding specialties forairducts, like Akulon K249-HG4. DSMAkulons are in the position to cover all ofour customers’ needs in this importantsegment.
Engine covers. Also for this segmentfit-for-use Akulon grades are availablelike K223-HGM24 (10% GF, 20%Mineral) and K220-HGM44 or K-FHGM44 (both 20% GF, 20% Mineral;highly flowable with superb surfaceappearance.These grades do offer the requestedcombination of high toughness andstiffness, of low warpage and goodsurface appearance, and of easy andspeedy processability, which explainsthe many approvals at all major OEMS.
Relay box, Akulon K224-HGR24.
Airducts, Akulon F249-HG4.
Secondary Air Supply (SAS) pump, Akulon K224-HG6.
Radiator grille, Akulon K224-HG3.
Acoustic engine coverAkulon K223-HGM24.
Air intake manifold, Akulon K224-HG6.
Akulon in electrical and electronic applications
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Polyamides are used in electrical orelectronic applications:low voltage switch gears;connectors, bobbins and electromotorparts. Below the main emphasis will bedirected towards low voltageswitchgears and towards connectors.Information on the other applications canbe obtained at our sales engineers orapplication development engineers.
Low voltage switchgear
The segment of ‘Low VoltageSwitchgear’ can be sub-segmented intothe following categories of applications(which are covered by the different IECstandards, quoted between brackets):- miniature circuit breakers; domestic
(IEC 898) or industrial (IEC 947)- residual current devices
(IEC 1008/1009)- fuses (IEC 269)- switches and relays (IEC 947-3)- contactors (IEC 947-4)- cabinets (IEC 439-5).
The main trends in these sub-segmentsare:- thermo set replacement- shift from halogen containing flame
retardant systems towards halogenfree and phosphorous free systems
- the integration of functions,miniaturization and designs withthinner wall thickness
- and the application of laser markinginstead of printing.
Property Standard Unit A B C D EFlammability IEC 707 Class FV 0 FV 1 FV 2 FH 1 FH 3Flammability UL 94 Class V-0 V-1 V-2 HB HBHWI IEC 695-2-2 Sec > 7 > 15 > 30 > 30 > 30HAI IEC 947-1 Arcs > 15 > 30 > 30 > 60 > 120
Residual Current Device (RCD), AkulonK223-KMV6, K222-KGV4.
Fuses, Akulon K223-KMV6, K222-KGMV14.
These trends lead to more stringentrequirements with respect to thethermoplastics used, especially due totrends in design, Comparative TrackkingIndex (CTI) requirements shift to ‘CTI ≥400 V’ and Relative Temperature Index(RTI) requirements towards ‘RTI electrical≥ 130 °C’ and ‘RTI mechanical ≥120 °C’. All this preferably realized in ahalogen free and phosphorous freesystem. Other requirements are:
Minimum general requirements: - Glow Wire Flammability Index of
960 °C- Ball Pressure >125 °C- specific combinations of Flammability,
Hot Wire Ignition and High Current ArcIgnition (according to IEC 947-1; seeTable 3).
Customer specific requirements:- short term and long term temperature
resistance- stiffness combined with good
elongation at break- specific CTI-value dependent on the
actual creep age distance realized inthe application
- specific values for other, specificelectrical properties (electric strength,resistivity,..)
- limited, controllable warp age level- colour consistency (base colour) and
colour stability (as well in processingas in use: both after a specifictemperature/time exposure).
This set of requirements explains whyPA6 (and specifically Akulon) is thepreferred material for these applications:
Miniature Circuit BreakerEnclosures: Akulon K223-KMV6, K222-KGMV14, K222-KGV4, K222-KMV5 andK223-KMV6.Other parts: Akulon K222-KGV4.
Table 3. Specific combinations of Flammability, Hot Wire Ignition and High-Current Arc Ignition.
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its melting point of 220 °C is sufficient towithstand the short-term temperaturerises. Its stiffness is the same as that ofPA66 up to 190 °C);with its high RTI values it can easily meetthe long-term temperature requirements.Typically continuous temperaturesseldom exceed 70-90 °C. There is however a trend to highercontinuous temperature exposures);it is available in halogen free andphosphorous free flame retardantversions, which also comply with the CTI≥ 400 V requirement;it is tough and easy process able.
Especially the halogen free andphosphorous free flame retardantrequirement in combination with a CTI ≥ 400 V is difficult to be met by PBT orPA66. Other deficiencies of thesematerials are: too much warp agesensitivity, less stiffness and strength atelevated temperatures, less impactresistance in the case of PBT and moredifficult process ability and limitedelectrical properties in the case ofphosphorous based flame retardantPA66. Despite its moisture absorption,PA6 still easily manages to meet thevarious specifications with respect todimensional stability and electricalrequirements.
Miniature Circuit Breaker (MCB), Akulon K222-KGV4.
Motorstarter, PA66 GF V-0.
Contactors, Akulon K223-HMS6.
Circuit breakers. Circuit breakersprotect wiring systems from over-currentsituations and protect equipment fromshort circuits. Ball pressure temperatureand glow wire flammability index areimportant requirements for domesticapplications (as laid down in IEC 898).Glow wire flammability index andcomparative tracking index arerequirements for industrial applications,as described in IEC 947-2. The deviceshave to exhibit high impact resistance(polyamide is preferred above polyester)and must pass cyclic thermal andmechanical endurance tests. AkulonPA6, in the standard colours such aselectro-grey RAL7035 and black, is usedas well for the enclosures as well forvarious internal parts.
Contactors. Contactors connect andinterrupt electrical power. In general theyare subject to higher currents thanswitches. They can be controlledremotely, or by an integrated switch, asfor example in motor starters. The mainmaterial related requirements aredescribed in IEC 947-4 and include aglow wire flammability index of 960 °C.Also the comparative tracking index isimportant here, because it is stronglyrelated to the level of design freedom ofthese contactors.
Table 4. The Akulon PA6 portfolio for the low voltage switchgear segment consists of:
K225-KS halogen free, unreinforced, UL94 V-0K222-KGV4 halogen free, 20% glass fibre reinforced, GWFI 960 °CK222-KGMV14 halogen free, 5% glass fibre reinforced, 20 % mineral reinforced,
GWFI 960 °C
K-FKGS6 halogen containing, 30 % glass fibre reinforced, UL94 V-0K222-KMV5 halogen free, 25% mineral reinforced, GWFI 960 °CK223-KMV6 halogen containing, 30 % mineral reinforced, GWFI 960 °C
(note: halogen free versions of the latter two are under development)
ContactorAkulon K225-KS, K222-KGV4.
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Switches and relays for industrialapplications. Switches connect orinterrupt electrical power. There exists awide range of switches, like rotaryswitches and push buttons. Theirrequirements are described in IEC 947-3. The main material-relatedrequirement is again glow wireflammability index. The CTI plays animportant role in designing thesedevices. This because of its relation toenvironmental pollution requirements. If acompact design is needed, materialsshould have a CTI-value as high aspossible (preferably > 600 V). In manycases additionally dimensional stability isrequired, while thermal requirements areoften not as high compared with MCB’sor RCD’s.
Connector applications
The segment of connectors can be sub-segmented into:- automotive connectors- PCB-connectors- industrial connectors (CEE)- terminal blocks- wire-to-wire-connectors- and various other type of connectors.
Below a special emphasis is given to thesub-segments of ‘’industrial connectors”and “terminal blocks”. Information onthe other sub-segments can be obtainedvia our sales engineers or applicationdevelopment engineers.
Industrial connectors (CEE). TheCEE-connectors (CEE = InternationalCommission on Rules for Approval ofElectrical Equipment) are found inindustrial environments as devices forsupplying and coupling of electricalpower. Important requirements for thismarket are laid down by the industrystandard EN 60309-1. It states thatconnector materials supporting currentcarrying parts must:- exhibit resistance to chemicals and a
ball pressure of at least 125 °C- impact resistance also at -25 °C- UL94 V-2 and resistance to ageing up
to 100 °C.
Other, more or less customer specificrequirements, are:- high stiffness to prevent creep age
and possible bad connections- high ductility because of film hinges
and dovetailing interconnections- and good flow ability because of thin
sections.
This set of requirements explains whyPA6 (and especially Akulon) is preferredabove PBT (which has a too low impactresistance, a limited flow ability and onlyUL94 HB in unreinforced version) andPA66 (which is too expensive). The mainAkulon grades used are F223-D(unreinforced PA, V-2), K224-G0 (PA6,50% GF) and K223-KMV6 (PA6, 30%mineral reinforced, V-2). Some areavailable in company specific colours aswell as in signal (cadmium free) colours.
Terminal blocks. Terminal blocks areeither modular or one-piece (multi-contact). They connect individual wiresby means of a screw or spring contact.They are primarily found in industrialswitch cabinets and on printed circuitboards (PCB’s) to provide the wire-to-board connection. Importantrequirements, as described in EN 60998and EN 60947, are: - high levels of CTI, HWI and HAI- and in addition, resistance to soldering
heat at 260 °C (pin-through-hole, wavesoldering technique). A trend isobserved towards surface-mount-technology. This implies: the necessityof the application of a high temperaturerestant material as Stanyl (PA46).
Other requirements are:- halogen and phosphorous free flame
retardancy (UL94 V-0 at 0.4 mm) incombination with a CTI level > 600 V
- a high flowability, because of thinsections down to 0.2 mm
- a low corrosivity in injection moulding- a high stiffness to prevent creep age
and possible bad connections- and a high ductility because of film
hinges and dovetailinginterconnections.
In the case of PCB terminal blocks arealso required:- a low warp age level (necessary for a
good fit to the PCB)- and high levels of stiffness and
strength, combined with low creeplevels (necessary for sufficient highlevels of pin retention).
The main Akulon grade used here isS225-KS (unreinforced PA66, halogenfree, UL94 V-0).10
Switch, Akulon K223-KMV6. CEE Connectors, Akulon F223-D. Terminal blocks, Akulon S225-KS.
Application areas outside of automotiveand electrical and electronicapplications, include railway systems,chair bases and general furnitureapplications, castor wheels, sportsapplications, consumer durables,building and construction and industrialgoods. This important market segmentmakes up about 40% of the polyamideinjection moulding market. Our AkulonPA6 grades are eminently suitable foruse in these applications.
Railway systems
Railway systems comprises in mostcases the insulators or railway pads. Forthis application good mechanicalproperties are required. In most casesAkulon K224-G6 is the best choice.
Power tools
For many years polyamide 6 has beenthe dominant material for power toolhousings because it is heat resistant,tough and process able. The heat ofelectric motors and the continueddownsizing of units result in highoperating temperatures in power tools.And as with lawn and garden, powertool manufacturers know the abuse theirunits might withstand. They wantmaterials that can take impact withoutfailure. In power tools colours andaesthetic appeal are important.Polyamide 6 delivers exceptional surfaceappearance with good colour stability.
Castor wheels
Polyamide 6 is also the preferredmaterial for castor wheels, which in thiscase means everything between furniturewheels and heavy-duty industrialapplications like air cargo containerwheels. Material in use is essentiallyunreinforced polyamide; ranging fromhigher viscous material like F130-C forhigh impact and mechanical strength toAkulon F223-D for less demandingapplications.
Sports
Polyamide 6 is also used in largeapplications in sport, like ski-bindingsand inline skates. DSM EngineeringPlastics has extensive experience withK224-TG9 for ski-bindings, because ofits excellent fatigue properties. For inlineskates, Akulon K224-PG6 is used, whichprovides high impact and mechanicalstrength.
Consumer durables
Consumer durables are an avery broadarea, which includes kitchen tools,consumer tools (like hammers andscrewdrivers) and garden tools (likehedge cutters, axes and scissors). Akulon K224-G6 is used for theseapplications, but also materials likeAkulon K224-PG6 or K224-PG8 areused if impact is required for theapplication. The latter material providesan excellent impact/stiffness balance.
Building & construction
Like consumer durables, this applicationarea is fragmented but contains onelarge application: wall plugs. Usuallypullout force and flexibility duringmounting of plugs are key requirements.Akulon F223-D and K223-P2 meet thesecriteria.
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Power tool, Akulon K224-G6.
Railway pad, Akulon K224-G6 and an insulator of Arnitel.
Ski-bindings, Akulon K224-TG9.
Other injection moulding applications
Various types of castor wheels,Akulon F223-D and F130-C.
Polyamide 6 and 66 can be used forextrusion processes in many differentapplications, due to its chemical andmechanical properties, which include:- chemical and mechanical resistance- high impact and creep resistance- low oxygen permeability- resilience- temperature resistance- fast processing.
Film
Akulon 6 is our range of polyamides 6 forextrusion and injection moulding. Theyare commonly used for the production ofmono and multiplayer films and made bycast and blown film extrusion methods.These films are mostly used for foodpackaging applications. The films can beboth thermoformed and bi-axiallystretched.
Monolayer films are used primarily insausage casings and sauce packagingpouches. Multiplayer films are used forcheese and meat packaging andmedical applications. DSM’s polyamideshave excellent mechanical properties,including very high puncture resistance.
Extrusion applications
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Polyamide is frequently used in mono& multilayer films. In multilayer film forfoodpackaging PA6 exhibits highmechanical protection due to anexcellent puncture resistance, goodbarriers against O2 and aroma’s, anda very high level of transparency.
Film for flexible packaging (multilayer); Akulon F126-C, F132-E, F136-C, F136-E and F136-EN.
F 1 32 EPolyamide type Viscosity AdditivesF = PA 6 1 = Extraction value/ determined C = lubricated
food contact approved in HCOOH E = lubricated &nucleated
S = PA66 2 = low extraction value, N = enhanced basic polymer suitable for thermoform all applications (incl. food behaviourcontact applications)
Table 5: Example of F132-E grade code with explanation of coding system.
They feature good barrier resistance tooxygen, carbon dioxide and aromas.Additionally they have very hightransparency. Akulon 6 also excels incritical properties like purity and low gel.
In food packaging, Akulon 6 is usuallyused with a polyolefine material (LDPE orLLDPE). A tie layer is needed to allowco-extrusion of these materials. DSMsupplies Yparex, a very suitable C8 andC6 LLDPE-based-tie-layer material. Thepolyolefines can also be added tomonolayer polyamide films by eitherlamination or extrusion coating.
More information about thecrystallization, barrier properties,mechanical properties and processing ofAkulon 6 is available in an extendedbrochure.
Semi-finished materials (stockshapes)
Stock shapes are semi-finished materialsand extruded or cast rods, mandrels,thick-walled tubes, thick sheets andprofiles. They are easily machined tomake all kind of products. The excellentproperties of engineering plastics givethem very high strength and rigidity,dimension stability, low creep, very goodtribological and electrical insulationproperties.
Products made from engineering plasticsinclude all kind of bearings, gear wheels,bushes, guide rolls, guide strips, pulleys,buffers, hammer heads, seals, scrapersand electrical insulation parts. The mostimportant engineering plastics for stockshapes are PA6, PA66, POM and PET.DSM Engineering Plastics offers PA6,PA66 and PET.
The main characteristics of PA6 and PA66 are:- high mechanical strength, rigidity,
hardness and toughness- good shock absorption- good resistance to fatigue- good sliding and bearing properties,
both dry and lubricated- excellent wear properties- good electrical insulation properties.
PA6. The combination of mechanicalstrength and rigidity with wearresistance, together with an excellentelectrical insulation and good chemicalresistance, make PA6 an ideal ‘universal’material for industrial and maintenanceparts. It is also suitable for use in dirty orsandy environments, for example forbearings on agricultural equipment, orsupport rolls for tracks.
PA66. Compared with PA6, PA66 hasslightly better tensile strength, rigidity,temperature resistance and wearbehaviour. However, the mechanicalextinction and the impact strength aremoderately lower.
There is a more extended brochure onthis subject available. This also includesPET and a comparison of DSM materialsto POM.
Convoluted tubes
Akulon is an excellent material to use astube for the protection of electrical wiringand cables. Due to its highertemperature resistance, flexibility andchemical resistance, these tubes areoften used in under-the-bonnet
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Grade DescriptionF126-C Grade with low viscosity, applicable for multilayer filmF132-E Grade with medium viscosity, nucleated for flat filmF136-C Grade with high viscosity, applicable for flat and blown filmF136-E Grade with high viscosity, nucleated for blown filmF136-EN Grade with high viscosity, improved thermoformabilityS240-C Grade with high viscosity, applicable for blown film
Table 6: Film grades.
Grade DescriptionF136-C High viscosity PA6 grade for rods and sheet F150-CZ Very high viscosity PA6 grade for big rods and vacuum seized
thick-walled tubeF160-Z Highest viscosity PA6 grade for thick-walled vacuum seized tubeS240-C High viscosity PA66 grade for rods and sheetS245-C Very high viscosity PA66 grade for big rods and thick-walled
vacuum seized tube
Table 7: Semi-finished grades.
Grade DescriptionF136-DH Heat stabilized grade for convoluted tubes.
Table 8: Convoluted tube grade.
applications in the automotive industry.The requirements for tubes in thesesegments, as well as in theelectrical/electronic markets, are verystrict, especially on the chemical andthermal properties of the material.
Still, in the machine construction marketmetal tubing is being used to a greatextent. But due to its weight and betterflexibility, there is a trend to use plasticsmore and more often. An emphasis onhalogen free material and safety issues,like smoke density, levels direct materialtowards polyamide.
Stockshapes.
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Akulon polyamide 6 and 66 are semi-crystalline engineering thermoplastics. Intheir solid state they show regularcrystalline structures dispersed in anamorphous phase. This basiccharacteristic is what determines howthe products react to heat, chemicalattack, glass reinforcement, or anynumber of other stimuli.
Dimensions
All thermoplastic materials shrink as theycool from their melt temperature.Crystalline materials like Akulon, tend toshrink much more than amorphousmaterials. The addition of filters andreinforcements to crystalline materialshas a dramatic reducing effect on mouldshrinkage (see Figure 1)
Unreinforced and mineral filled Akulongrades are largely isotropic with respectto shrinkage. Shrinkage in the directionof flow is more or less equal to shrinkageacross flow. On the other hand, glassreinforced grades show anisotropicproperties. Due to fibre orientation,shrinkage values in the direction of floware often substantially smaller thanshrinkage values across the direction offlow. This is the basic reason for thewarpage which often occurs in partsmoulded with glass reinforced crystallinematerials.
Moisture absorption plays a major role inthe prediction of dimensions in Akulonmaterials (see Figure 2). Moistureabsorption is a time and humiditydependent, reversible process, whichcontinues until equilibrium is reached. Achange in the moisture content will resultin different product dimensions. Duringthe use of the product the designershould anticipate varying humidityconditions. The moisture absorption ofreinforced grades differs from those ofreinforced grades. Moisture also effectsother important properties (howevermainly at temperatures below 100 ºC).
Designing with polyamides
Figure 1.Linear mouldshrinkage (2-3 mm)for PA6 and PA66.
Figure 2.Moisture absorptionof PA6 and PA66.
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Yield stress, modulus of elasticity andhardness decrease with increasingmoisture absorption. Toughness, orimpact resistance, shows considerableincrease.
Surface appearance
Some Akulon polyamides are capable ofa high level of reproduction of the mouldsurface. In general, unreinforced gradesoffer the best reproduction and glassreinforced the worst. Mineral filledgrades fall somewhere in between.Polyamide 6 will almost alwaysreproduce a mould surface moreaccurately than polyamide 66. All theseguidelines are particularly true of highgloss moulds. Often textures can beused to hide the surface imperfectionsinherent to moulding these products.
Wall thickness
Performance requirements determine thewall thickness of a given part. Wallthickness should be minimized toshorten moulding cycles, reduce partweight and optimise material usage. Theminimum wall thickness, which can beused in injection moulding, depends onthe size and geometry of the part andthe materials flow behaviour. In general,Akulon type 6 grades flow easier thantype 66 materials.
Uniform wall thickness assists consistenteven filling of the mould and results inmore predictable shrinkage. Whenvarying wall thickness are unavoidablefor reason or design, there should begradual transitions.
Corners and radii
Sharp internal corners and the resultingstress risers are among the mostcommon causes of structural plasticproduct failure. All polyamides aresomewhat notch sensitive and glassreinforced versions are particularlysusceptible. The stresses arising frominternal corners can be minimized by theuse of generous radii. In general, internalradii equal to one half the wall thicknessbest distributes the loads over thesurface of the part. Smaller radii causesstress concentrations. Larger ones donot significantly help the situation.External corners should maintain aconstant wall thickness around theradius of the internal corner. Thisreduces variations in wall thickness andhelps prevent warpage and sinks.
Ribbing
Ribs provide a number of advantages tothe part designer. They may increasestrength and stiffness. They can reduceweight and shorten cycle times byeliminating heavy cross sections, whichcan substantially reduce costs. Ribshave their problems, however. Sinkmarks may appear on the surfaceopposite the ribs. Often these can behidden by the strategic use of texture. Ifproper design rules are not followed, ribsmay also cause stress at theirintersection with the wall of the part.They can be helpful for the productdesigner if they are only used when theyare necessary to provide themechanical performance ofthe application.
Tailgate handleAkulon K224-HG6.
Assembly
Akulon polyamides are suitable for anumber of assembly techniques,including heat staking, sonic welding,moulded-in or post-mould-insertionthreaded inserts and snap fits. Whilemaking allowances for any of theseassembly methods, the designer shouldkeep in mind the standard design rulesfor polyamides, i.e. avoiding notches or - in the case of snap fits - exceeding thestrain limits of the material, etcetera.
While adhesive bonding of polyamideshas been done successfully, the superiorchemical resistance makes this a difficultoption. For the best results, therecommendations of the adhesivemanufacturer should be followedprecisely.
Both heat staking and ultrasonic weldingare used to stake or weld Akulon. Otherwelding techniques frequently used incombination with Akulon are vibrationand laser welding. PA6 grades usuallyoutperform PA grades with respect tothe weld strength achieved after thewelding process. Lower filler contentgrades typically perform better andcause fewer processing problems thanhighly reinforced versions do.
Machinery
Akulon polyamides can be processed onstandard plastic processing equipment.Typically, general purpose screwdesigns (i.e. compression ratios of about2.5;1) and sliding check rings work best.For unreinforced grades, polyamide orreverse taper nozzles work well, whilereinforced grades typically do better withgeneral purpose nozzles. These tend toreduce shear and provide bettermechanical properties and, since thereinforcement inhibits drool, the reversetaper of a polyamide nozzle doesn’t addmuch benefit.
Tooling. Akulon polyamides needsimilar specific tooling requirements asother polyamide materials. Forunreinforced Akulon, the gates andrunners can be very small, to savematerial scrap and reduce cycle times.Larger parts and/or more highlyreinforced materials require moregenerous gates and runners. However,sub-gates are the most commonbecause of their automatic de-gatingcapability.
Most of the major hot manifoldmanufacturers have built manifoldswhich have been successfully used withAkulon polyamides.
Unreinforced materials use polyamide orlong reversed tapered nozzles to reducedrool. Reinforced products generallywork better with general purposenozzles.
It is very difficult to accurately predictshrinkage for highly crystalline materials.Unreinforced polyamides tend to havevery high shrinkage. In glass reinforcedgrades transverse shrinkage may be50% to 100% more than the linearshrinkage value reported in mostproduct data sheets. As a result, glassreinforced polyamide parts have apropensity to warp during the post-mould shrinkage phase. For precisionparts with very tight dimensionaltolerances, it is best to build a prototypemould. It requires the same gate type,size, location, etcetera as the productionmould to predict shrinkage and warpageaccurately.
Auxiliary equipment. The key piecesof auxiliary equipment include thematerial dryer, mould heater and scrapgranulator. Dryers must be sized tohandle the throughput rate of themoulding machine used. However, thekey requirement of the dryer is its abilityto maintain a dew point between -40and -30 °C. Dew points above this leveldo not facilitate drying. Mould heat canbe provided via water or oil. In general,the temperature requirements of Akulonbetween 50 and 90 °C can be met usingwater.
Scrap granulators should be able toproduce uniform particles which can beblended with virgin pellets withoutadversely affecting the homogeneity ofthe melt. Therefore the granulator screenshould be sized accordingly.Additionally, the blades must be sharpenough to cut the scrap withoutproducing excessive amounts of fines.
Material handling
Akulon granules are supplied dry inairtight moisture proof packing. It isimportant to prevent moisture absorptionbefore moulding, when working withpolyamides. Akulon is hygroscopic andabsorbs moisture from the air relativelyquickly. Should this occur prior tomoulding, there can be an adverse effecton the quality of the moulding. Duringstorage, containers should be keptclosed and undamaged.
During moulding the following measuresare recommended:- open the container just before filling
the hopper- close the container securely if all
contents have not been used- keep the hopper closed- bring cold granules up to ambient
temperature in the moulding shopwhile keeping the containers shut.
Every batch is tested for moisturecontent and viscosity level afterproduction. A certificate with relevant lotdata can be delivered with the materials.
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Injection moulding of polyamides
Room-installationAkulon K222-KGMV14, K223-HM6 and K225-KS.
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All polyamides are hygroscopic andrequire special handling to prevent theabsorption of moisture from theatmosphere. Akulon polyamides arepackaged at a maximum level of 0.15%moisture content. Moisture levels above0.2% will cause surface splay on themoulded parts.In order to achieve the best appearanceand performance Akulon polyamidesshould be dried to the recommendedlevels. The equipment for this taskincludes dessicant bed dryers, which arecapable of holding the dew point of thecirculating air to between -40 and -30 °C.
Safety. Under normal conditions,Akulon does not present a toxic hazardthrough skin contact or inhalation.During processing contact with thepolymer and inhalation of fumes shouldbe avoided. A material safety data sheet(MSDS) can be requested from yourlocal DSM account manager.
Cylinder temperatures. Akulonpolyamide 6 with a melting point of 220 °C, can be processed within abroad temperature range, for example230-290 °C. The melting point of Akulonpolyamide 66 is 260 °C. It can beprocessed at temperatures between 270 and 300 °C (see Figure 3 forrecommended processing parameters).Keep in mind that these can varydepending on the specific grade and thesize and condition of the mouldingmachine.
Use of regrind. Regrinding levels of25% hardly influence short and/or longterm properties of Akulon. They aretherefore recommendable under theprerequisite that the regrind must be dryas moulded and free from dust and/orlongs.
Akulon Polyamide 6 Mould Melt Nozzle Front Center Rear Drying°C °C °C °C °C °C °C
Unreinforced 55-80 240-265 235-260 235-255 230-250 225-245 80Glass Reinforced 55-80 270-280 260-270 265-275 275-290 270-280 80
Akulon Polyamide 66Unreinforced 55-80 270-295 270-295 280-295 275-295 270-290 80Glass Reinforced 55-95 280-305 280-295 275-290 290-300 280-295 80
Figure 3. Guideline for cylinder temperatures.
Relay boxAkulon K224-HGR24.
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Positioning Akulon in the world ofthermoplastics
Polyamides are characterized by thepresence of amide-groups (-NH-CO-)in the main polymer chain. Chemicallythe aliphatic polyamides may be dividedinto two types:- those based on diamines and diacids
(like PA66 and PA46). PA66 isproduced by a polycondensationreaction from hexamethylene diamineand adipic acid
- those based on amino acids orlactams (like PA6, PA11 and PA12).PA6 is produced in a ring-openingpolymerization process starting fromcaprolactam.
Commercial use of the aliphaticpolyamides is dominated by PA6 andPA66. They are characterized in Table 9.
The Akulon product line comprises bothpolyamide 6 (PA6) and polyamide 66(PA66) grades. PA6 and PA66 belongstogether with the polyesters PET andPET and the polyacetal POM to thesegment of semi-crystalline engineeringplastics. Semi-crystalline indicates thatthese materials contain a certain fractionof crystalline domains. They are to alarge extent responsible for the excellenttemperature and chemical resistance.The materials in this segment do yield ahigher temperature resistance (shortterm as well as long term) than thecommodity materials (like PE, PP, PS
Characteristic properties of Akulon (PA6 and PA66)
Table 9. Characteristics of aliphatic polyamides.
and PVC and the amorphousengineering plastics ABS, PC andABS/PC). Only materials belonging tothe high performance material segment(like PA46, PPS, PEI, PES and LCP) doexhibit an even higher temperatureresistance.
The main characteristics of AkulonPA6 and PA66 are:- an excellent short term heat resistance
due to the high melting points of 220 °C and 260 °C
- high stiffness and strength at elevatedtemperatures above 100 °C
- high creep resistance, especially atelevated temperatures
- good long-term heat resistance,especially when expressed in absolutestiffness/strength levels measured atelevated temperatures after the heatageing exposure in air. This is calledthe Absolute Real Operating (ARO)value concept
- outstanding toughness behaviour,especially important at lowtemperatures (23 °C and -40 °C),
- excellent fatigue resistance behaviour
- good resistance against oils andchemicals
- fast cycling properties combined withan excellent flow behaviour atprocessing temperatures, withoutshowing any signs of flash
- limited dimensional stability due to theabsorption of moisture.
This combination of properties, whichwill be discussed more detailed in thefollowing chapters, makes Akulonexcellently suitable for high performancetechnical applications in the automotive,electrical/electronical and general, otherindustries. In the following sections PA6and PA66, among themselves, arecompared with the polyesters PBT andPET.
Temperature performance
The temperature performance of everyengineering plastic can be described by:- a peak temperature resistance or a
short term temperature resistance,as indicated by a melting point, a Vicator a Heat Distortion Temperatureand/or a certain level of stiffness andstrength at a certain elevatedtemperature
- resistance to long-term heatexposure and oxygen containingenvironment at high(er) temperaturesin combination with or without anapplied load
Power toolAkulon F232-D, K224-G6 and K224-TG9.
Tm Tg HDT* Crystallinity Level/Rate(°C) (°C) (°C) (%)
PA6 220-225 60 210 30-50/medium-fastPA66 260-265 65 255 50/fastPA46 295 80 290 70/ultrafast
* for GF-contents > 30 %.
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- with load: creep resistance,respectively without load: ContinuousUse Temperature or Absolute RealOperating-value.
Short term heat performance. Intoday’s high tech world the performanceof engineering plastics over a widetemperature range is often of criticalimportance. An indication for the short-term temperature performance of amaterial is its stiffness and strength levelat elevated temperatures. For instance,between 100 °C and 200 °C thestiffness/strength level should beconsidered as is the critical level todesign for, since room temperaturelevels for stiffness/strength are muchhigher (even after moisture absorption) ingeneral.The shear modulus offers one of themeans of measuring and comparing thevariation of the stiffness of plasticmaterials with changing temperature. Itshigh level of crystallinity in combinationwith its high melting point enablesAkulon to retain its stiffness to ahigh extent at elevatedtemperatures. This ensures eithermore safety margins for criticalapplications in comparison to othercompetitive materials like polyesters(see Figure 4). It also implements thepossibility of the reduction of the wallthickness of the part. lt also should benoted that up to 185 °C there is hardlyany difference between the stiffnessof PA6 and that of PA66. Only above 185 °C PA66 exhibits a clear advantage.
Figure 4a. Stiffnessversus temperature
Figure 4b. Stiffnessversus temperature
Engine coverAkulon K220-HGM44.
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Stanyl (PA46) of course outperformsboth polyamides with respect to stiffnessand strength at all elevated temperaturesbecause of its higher crystallinity level.
Other indicators of the stiffness level aremore suitable as a design criterion thanthe shear modulus (as used in Figure 4).Think of the elasticity and/or the flexuralmodulus. Polyamides properties likethese and tensile or flexural strengthmerely depend on ambienttemperatures, moisture contents, heatageing exposures, reinforcers or otheradditives (lubricants, pigments) andmoulding conditions. For an examplesee Table 10, where, by addingreinforcements, stiffness levels areincreased significantly. The high stiffnessof Akulon at elevated temperatures(especially above 100 °C) offers newopportunities for designing with thinwalled parts thus achieving cost andweight reductions.
Figure 4c. Stiffnessversus temperature
Table 10. Stiffness at various conditions and various GF reinforcement levels.
Property PA6 PA66 PA46 PBT PET
E-modulus (MPa) Unreinforced Unreinforced Unreinforced Unreinforced Unreinforced23 °C – dam 3600 3300 3300 2700 250023 °C – 50% RH 1600 1600 1000 2700 2500150 °C 400 400 700 200 300E-modulus (MPa) 30% GF 30% GF 30% GF 30% GF 30% GF
reinforced reinforced reinforced reinforced reinforced23 °C – dam 10000 10000 10000 10000 1100023 °C – 50% RH 6000 6500 6500 10000 11000150 °C 4000 4000 5000 2700 3000170 °C 3500 3500 4700 2400 2700E-modulus (MPa) 50% GF 50% GF 50% GF 50% GF 50% GF
reinforced reinforced reinforced reinforced reinforced23 °C – dam 16000 16500 17000 16000 1800023 °C – 50% RH 10000 11000 10500 16000 18000150 °C 5500 6000 8000 4000 5500
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Figure 5. Creep modulus
The melting point in combination withthe Heat Distortion Temperature (HDT)gives another good impression of thepeak temperature resistance under acertain load. The HDT is the temperatureat which a test bar is deformed to agiven extent. This is related to a certainlevel of stiffness at the elevatedtemperature. Because of its excellentretention of the stiffness at highertemperatures the HDT-rating of Akulon(210 °C for 30% glass fibre reinforcedPA6 and 255 °C for PA66) is higher thanthat of other engineering plastics (PBTyields only 190 °C).
Long Term TemperaturePerformance: creep Resistanceat elevated temperatures. Foroptimum performance and maximumlifetime engineering plastics, which aresubjected to long-term loading, musthave a high creep resistance (i.e. a lowplastic deformation level under a certainapplied load). Materials specifications forengineering parts therefore often includea creep modulus, defined as the ratio ofa constant load and a time dependentdeformation level, or a maximumallowable elongation. Exposure to highertemperatures results in lower levels ofcreep moduli. Akulon’s high level ofcrystallinity results in a high retention ofthe stiffness at elevated temperatures(above 100 °C). It therefore gives rise toa creep resistance that is superior to thatof other engineering plastics. Again, upto certain temperatures and exposuretimes PA yields a similar performance asPA66 (see Figure 5).
Figure 6. Different properties of PA6 30% GF, HS (23 °C) after heat ageing at 170 °C.(Charpy Notched in kJ/m2, Tensile Modulus in MPa, Tensile Elongation in %, TensileStrength in MPa).
Heat ageing resistance in air.Designers must know the performancelevel of the material after exposure ofthousands of hours to heat in an oxygenenvironment. The performance (the heatair ageing resistance) can be expressedin various ways. To monitor theperformance after heat ageing over time,different parameters can be selected,like strength, stiffness, impactresistance, elongation at breakmeasured either at room temperature(see Figure 6) or at the elevatedtemperature. Again, the results of thesemeasurements can be displayed invarious ways. In a relative way viaretention levels or via relativecharacteristics like Continuous UseTemperature (CUT) and RelativeTemperature Index (RTI), or in anabsolute way like in the Absolute RealOperation Value concept (which showsthe absolute value of strength measuredfor instance after ageing for 5000 hoursat 150 °C).
The Continuous Use Temperature isfrequently used in the automotiveindustry as a selection criterion. It isdefined as the temperature at which agiven mechanical property (usuallytensile strength or impact resistance,since stiffness only increases after heatageing and since tensile elongationshows a too sharp, non discriminatingdrop for all materials) of the materialdecreases by 50% within a certainperiod of time (usually 500,1000, 5000,10.000 of 20.000 hours). From Figure 7and 8 it follows that the CUT of 30%glass fibre reinforced Akulon PA6 at5000 hours is 185 °C (the drop in tensilestrength is 50% after 5000 hours ofaging at 185 °C). This result is higherthan that of 30% glass fibre reinforcedPA66, which shows a 50% drop alreadyafter 5000 hours at 170 °C.
The Relative Temperature Index asgiven by UL, frequently used in E&E,can be considered to a certain extent asa CUT for very long half lifetimes, ranging
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Figure 8. Arrheniusplot for ageingresistance.
Figure 7. Tensilestrength (23 °C)after heat ageingat x °C.
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Property PA6 PA66 PA46 PPA
ARO 5000 hrs Strength at high temp. (MPa) after ageing at high temp.150 °C 80 70 110 90170 °C 70 50 90 80
CUT 5000 hrs (°C) 185 130- 170* 170 185
E-modulus (MPa)150 °C 4000 4000 5000 4000170 °C 3500 3500 4700 3500
Table 11. Heat Ageing Resistance and Stiffness of various 30% GF reinforced polyamides.(* depending on the exact heat stabilizer package and content used: Akulon PA66’s level is170 °C).
between 60.000 and 100.000 hours.Also here, the RTI of 140 °C for heatstabilized PA6 30% GF proves to besuperior to the one of 130 °C for PA66.
Absolute Real Operating Value afterheat ageing yields for designers morerealistic comparisons between thevarious materials since it overcomes themajor drawbacks of the CUT- and theRTI-concept: in these last concepts onlyretention of properties is considered andproperties are only measured at roomtemperature after the heat ageing.Certain materials, starting at a very lowlevel but retaining to a high degree, arebetter rated in CUT-terms than othermaterials that start at a higher level andshow a stronger reduction. The latterhowever can in absolute values stilloutperform the former materials after theheat ageing exposure. Next to that, theCUT-concept is based onmeasurements of properties at roomtemperature, whilst the more criticaldesign levels for stiffness and strengthare to be expected in the elevatedtemperature range (as demonstrated inShort Term Heat Performance). The ARO-concept, the only truemeasure, is demonstrated in Figures 9to 12, which show once more thesuperiority of PA6 to PA66 after heatageing (see also Table 11). The ARO-performance of Akulon PA6 comes evenclose to that of various aromaticpolyamides (PPA). Only Stanyl (PA46)outperforms PA6 and PPA in thisrespect. From the combination of thesecurves with curve 5 it follows that,despite the slight, non-significantdifference in starting value for stiffnessand strength, heat stabilized PA6 with30% glass fibre easily can replaceheat stabilized PA66 with 30% glassfibres!
Clutch pedalAkulon K224-HG8.
Note: ARO is the only true measure for heat ageing resistance.
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Figure 9. Tensile strength (23 °C) after heat ageing at 150 °C. Figure 10. Tensile strength (150 °C) after heat ageing at 150 °C.
Figure 11. Tensile strength (23 °C) after heat ageing at 170 °C. Figure 12. Tensile strength (170 °C) after heat ageing at 170 °C.
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Toughness, fatigue and wearproperties
Whilst tensile and flexural stiffness andstrength decrease with increasingtemperatures (similar curves as tensileand flexural modulus), toughness levels(elongation at break, impact resistance)increase with increasing temperatures.The critical level to be designed for istherefore not the level at elevatedtemperatures, but the level at roomtemperature (23 °C) or lower (-30 or -40 °C). Even at temperatures below 0 °C the notched and unnotchedimpact resistance values of Akulonremain at a high level. As can be seenfrom Table 12 even in a dry-as-moulded(dam) state the polyamides outperformthe polyesters, which facilitatesproduction and assembly steps.Combined with an unequalled level ofelongation at break Akulon offers anoptimal solution for thin walled parts,snap fits, film hinges and insertmouldings. Table 12 also shows thatPA6 is again superior to PA66 andthat the effect of different amounts ofglass fibre reinforcement is different forboth toughness parameters. Theelongation at break level decreases,whilst the Charpy and lzod impactresistance increases with increasing theamount of glass fibres.
Engineering parts are frequentlysubjected to dynamic loads andalternating stress levels. In order topredict the performance of plasticmaterials under these conditions thefatigue resistance is measured byplotting the stress level variation againstthe number of cycles till break enduredunder continuous prestress (the socalled ‘Wöhler diagrams’). The high
Property PA6 PA66 PBT PET
UF UF UF UFTensile Elongation (%) 20 20 20 20Charpy Notched (kJ/m2) 8 7 5 5Charpy Unnotched (kJ/m2) NB NB NB NB
30% GF 30% GF 30% GF 30% GFTensile Elongation (%):- dry as moulded 3.5 3.0 3.0 2.5- conditioned at 50% RH 5 5 3.0 2.5Tensile Strength (Mpa) 180 185 140 160Charpy Notched (kJ/m2):- dry as moulded 13 11 11 11- conditioned at 50% RH 30 20 11 11Charpy Unnotched (kJ/m2) 95 80 65 50
50% GF 50% GF 50% GF 50% GFTensile Elongation (%) 3.0 2.5 2.5 2.0Charpy Notched (kJ/m2) 22 17 11 12Charpy Unnotched (kJ/m2) 100 85 55 55
Table 12. Toughness at room temperature of polyamides (dam) versus polyesters.
Inline skateAkulon K224-PG6.
stiffness level in combination with thehigh toughness and the use of superiorglass fibre qualities implies a superiorfatigue resistance for Akulon incomparison to that of most otherengineering plastics.
Akulon has an excellent abrasion (orwear) resistance. It outperforms manyother engineering plastics, like POM,under most conditions but especially atelevated temperature conditions. Thefriction coefficients of standard grades ofthese thermoplastics are quite similar,but Akulon can outperform thesematerials because of its higher PV-rating(see Figure 13).
It permits higher pressures or velocitiesto be used in combination with Akulon.Modified Akulon grades (unreinforced aswell as glass fibre reinforced) areavailable with even better wearproperties. They make externallubrification redundant. Its smooth andtough surface, combined with itsstiffness at elevated temperatures,makes Akulon an ideal material forsliding parts.
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Water absorption and hydrolysisresistance
Like most polyamides, Akulon absorbsmoisture reversibly from the environmentuntil it reaches an equilibrium (see Figure14). PA6 absorbs more water thanPA66, especially under high humidityconditions. But the resultingdimensional change is still of asimilar order. The use of polyamides isnot recommended when dealing withapplications with very tight tolerances.This with respect to dimensions. In thiscase polyesters could be considered.Although it should be checked whethertheir hydrolysis resistance level isappropriate, because the hydrolysisresistance of polyesters is rather poor.Polyamides are superior with respect tothis. Note however, that for manyapplications the dimensional stabilityof polyamides is ‘good enough’!Absorbed water acts as a plasticiserreducing strengths and moduli (see Table10) and increasing the toughness of aplastic (see Table 12). Although at roomtemperature the stiffness and strength ofPA6 is more reduced by the moistureuptake than those of PA66, this differencecan be considered to be non-significant.This because Akulon is mainly being usedin market segments, which havetemperature requirements above 100 °C.This leads to the critical design level to belocated at the elevated temperature(strength at 150 °C is still lower than theconditioned value at 23 °C) and thusrendering the influence of the waterabsorption on mechanical properties tobe in general neglible.
Figure 13. Wear andfriction behaviour PA6 30% GF.
ASTM D-3702 ThrustwaterTest; Equilibrium wear (k)Factor Akulon K224-HG6.
Figure 14. Moisturecontent vs relativehumidity.
Cable channelsAkulon K224-HLG3.
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Chemical Resistance (includingresistance against oils and otherautomotive fluids)
Polyamides are well known for theirresistance to a wide range of chemicals.Especially, when expressed again via theARO-concept, Akulon’s good resistanceto different types of oil (see Figure 15)and greases makes it an ideal materialfor applications in the automotiveindustry - particularly under-the-bonnet -and for industrial applications in gearsand bearings. Akulon is like otherpolyamides attacked by strong mineralacids and absorbs polar solvents.
Note: polyesters are attacked by strongbase solvents and also by moisture(hydrolysis). On request, data concerningthe resistance of Akulon to variouschemicals and solvents are availablefrom your local DSM sales office.
Electrical properties,flammability and UL-classifications
As most other engineering plasticsAkulon exhibits similarly high levels ofsurface and volume resistivity, dielectricstrength and comparative trackingresistance. The exact levels of theseproperties depend however on thespecific grade, temperature andmoisture content. In general, these levelswill remain high enough in order to fulfilcritical application requirements. Thisfact, in combination with its very highpeak temperature resistance and its hightoughness level, makes Akulon anexcellent choice for electrical andelectronical connectors, circuit breakerhousings, electromotor parts, bobbinsand switches.
Figure 15. Akulon oilresistance: PA6 30%GF in motor oil.
Power steering fluid tanksAkulon F232-D.
A number of halogen free or halogencontaining flame retardant grades ofAkulon are available, rated according tothe Underwriter Laboratories (UL) 94classification, either V-0 or V-2 (GWFI of960 °C at 1.6 mm). The unmodified,unreinforced Akulon grades are rated V-2 and the glass fibre reinforced gradeswithout flame retarder are rated HB.Several other UL-classifications havebeen obtained for different Akulongrades as well (see UL File E 47960Components Plastics at UL’s websitedata.ul.com). A complete overview of the total systemrating and more detailed informationconcerning optimal processing withAkulon is available at your DSMSales Office.
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After treatments
Plastic parts often have to undergo afinishing operation after the actualproduction step. This step can either befunctional (machining, gluing, wending,screwing or snap fitting) or decorative(vacuum metallization, electroplating,painting, printing or laser printing). Ingeneral, with respect to these aftertreatments the same recommendationsas for the aliphatic polyamides areapplicable for Akulon. Because of itsrelatively high polarity, the adhesionbehaviour of Akulon usually will be quitegood, especially when the finishingtechnique is applied on ‘dry as moulded’parts. Welding (vibration, ultrasonic,laser) and/or snap fitting are thepreferred bonding techniques for Akulon.Welding should be performed with ‘dryas moulded’ parts in order to achieveoptimal weld strengths and to avoidblistering and severe polymerdegradation. Note that PA6 gradesoffer in general a much higher weldstrength, resulting in higher burstpressure levels, than correspondingPA66 grades. By its superb level ofelongation at break - especially after moisture uptake - (seeTable 12) snap fits designed in Akulonoffer many advantages in comparison tothe other joining techniques.
Laser printable Akulon.
Figure 16. Positioningof thermoplastics.
Decorative finishing techniques onAkulon are next to the decorative reasonapplied for reasons like product liability(printing and laser printing) orfunctionality (metallization). Due to thebetter surface appearance ofreinforced grades, PA6 grades arepreferred above the correspondingPA66 grades. More detailed informationis available at your DSM Sales Office.
Basic comparison polyamidesversus polyesters and PA6 versusPA66
In the previous sections PA6 and PA66are compared with polyesters andamong themselves. In this section and inFigure 16 a short positioning resume ispresented.
Polyamides versus polyesters
Advantages of polyamides:- higher stiffness and creep resistance at
elevated temperatures (above 100 °C)- better heat ageing resistance in terms
of the ARO-values at elevatedtemperatures
- higher toughness at low temperatures;- more fatigue resistance- excellent wear resistance
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- less sensitivity for hydrolysis in theapplications and for moisture duringprocessing
- halogen free flame retardancy inreinforced PA6 grades is possible.
Advantages of polyesters:- better dimensional stability under
humid conditions- better retention of electrical properties
as function of temperature and/orhumidity
- more chemical resistance in aceticenvironments.
Polyamide 6 versus polyamide 66
Advantages of PA6:- better heat ageing resistance in terms
of the ARO-values at elevatedtemperatures
- higher toughness at low temperature- easier process ability (broader
processing window)- higher weld strength after various
welding processes- better surface appearance for
reinforced grades- halogen flame retardancy in reinforced
PA6 grades is possible.
Advantages of PA66:- higher melting point- more stiffness/strength only above
185 °C.
The advantages above can lead tosubstantially increased profit and/orsafety margins in your applications.Higher stiffness levels at elevatedtemperatures and higher ARO-valuesimply for instance either savings onmaterial costs, through the possibility toreduce the wall thickness of theapplication, or a higher safety margin,
Table 13. Akulon product coding.
Relay boxes, Akulon K224-HGR24.
when keeping the wall thickness thesame. An easier process ability (a broader processing window incombination with a lower melting point)leads to a possibility to achieve lowerprocessing costs as a result of lowerenergy costs and/or lower cycle times(due to the lower melting point) or to apossibility to reduce wall thickness evenfurther as a result of a better flowabilityof the material by using higherprocessing temperatures. Highertoughness levels leads to lower rejectlevels in production or like higher weldstrengths to higher safety margins inthe applications, whilst better surfaceappearance leads to an improvedimage in the market place.
Thus in summary, a lot ofeconomical reasons to chooseAkulon (especially the PA6product line) as the most optimalmaterial for most of yourapplications!
K 2 2 4 H G 6F, K = PA6S = PA66
1 = Film extrusion2 = Injection moulding
04 = indication of solution viscosity6
B = easy mould release N - thermoformable (film)C = lubricated P = toughenedD = nucleated, easy mould release Q = FDA approvedE = nucleated, lubricated R = glass-sphere reinforcedF = improved flow S = self extinguishing (V-0)G = glass fibre reinforced T = incrementally toughened (TG)H = heat-stabilized, limited colour stability V = flame retarded (not V-0)K = heat-stabilized, good colour stability W = reserved for ‘laser writable’L = light/UV stabilized X = additional, specific feature M - mineral reinforced (e.g. high burst pressure)
Reinforced content# x 5 = % glass (e.g. 3 x 5 = 15% glass)
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DSM Engineering Plastics product portfolio
Akulon® Polyamide 6 and 66 in both unreinforced and reinforced grades, including flame retardant products.polyamides
Akulon® Ultraflow™ Polyamide 6 reinforced grades, easy flowing, lower processing temperatures,polyamide faster crystallization speed, shorter injection and holding time, reduced cycle time.
Akulon® XP Xtreme Performance PA6 for filmpolyamide
Arnite® PBT and PET based materials, including unreinforced, reinforced, and flame retardant grades,thermoplastic polyester offering excellent dimensional stability and low creep with good chemical resistance.
Arnitel® High performance elastomers based on polyester.copolyester elastomers
Stamylan® UH A high performance polymer having outstanding abrasion resistance in combination with excellentultra high molecular impact and chemical resistance, low coefficient of friction and very good electric and dielectricweight polyethylene properties.
Stanyl® PA46 High temperature polyamide which bridges the price-performance gap between 46 polyamide traditional polyamides and high-performance materials.
Stanyl® PA46 An innovative PA46 which combines excellent mechanical performance High Flow™ with (LCP-like) high flow and low warpage resulting in cost-savings for demanding high-end46 polyamide applications.
Stapron® Unreinforced and reinforced PC-blends. Flame retardant grades based on halogen free systems.PC/PET-blend
Xantar® Unreinforced, reinforced, and flame retardant grades with outstanding impact resistance, polycarbonate dimensional stability, and high heat deflection temperature.
Xantar® C A new generation PC/ABS-blend providing improved flow, simultaneously increasing PC/ABS-blend impact and stress-crack resistance, while optical appearance and stability are on a very high
and consistent level.
Yparex® This family of extrudable adhesive resins consists of polyolefins with incorporated functional groups,adhesive resin which provide the necessary bond between polyolefins and polar materials (e.g. PA, EVOH, glass) or
metals (e.g. steel, aluminium, brass, copper).
® Registered tradenames of DSM
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EuropeThe Netherlands
DSM Engineering PlasticsPoststraat 1P.O. Box 436130 AA Sittard
Tel. +31 46 47 70450Fax +31 46 47 73959
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DSM Engineering PlasticsP.O. Box 33332267 West Mill RoadEvansville, IN 47732-3333
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Internetwww.dsmep.comwww.dsm.com
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All information supplied by or on behalf of DSM inrelation to its products, whether in the nature ofdata, recommendations or otherwise, is supportedby research and believed reliable, but DSM assumesno liability whatsoever in respect of application,processing or use made of the aforementionedinformation or products, or any consequencethereof. The buyer undertakes all liability in respectof the application, processing or use of theaforementioned information or product, whosequality and other properties he shall verify, or anyconsequence thereof. No liability whatsoever shallattach to DSM for any infringement of the rightsowned or controlled by a third party in intellectual,industrial or other property by reason of theapplication, processing or use of the aforementionedinformation or products by the buyer.
© DSM Engineering Plastics Marketing Communications Europe(SLH 11-2003)
Sales offices EuropeDSM Engineering Plastics