Luran® SAcrylonitrile-styrene-acrylatecopolymer (ASA and ASA+PC)

ApplicationsRangePropertiesProcessing

Luran S grades

offer a broad range

of exceptional

properties. They

feature high thermal

stability, good

chemical resistance

and excellent resist-

ance to weathering,

ageing and yellow-

ing. Therefore,

Luran S is used in

applications which

involve exposure to

extreme conditions.

Luran S has a broad range of applications...

... in automotive construction

... in electrical engineering and electronics

... in sport and leisure

... in a wide variety of indoor and outdoor uses

Luran S and its characteristic properties

The Luran S range at a glance

Mechanical properties

Resistance to weathering

Long-term heat resistance

Fire performance

Electrical properties

Antistatic performance

Resistance to chemicals

Permeability to water vapour and gases

Processing of Luran S

General information

Injection moulding

Extrusion

Blow moulding

Thermoforming

Machining and post-processing

Safety information

Luran S and the environment

Supply, literature references

Supply

Literature references

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Typical Luran S applications in the auto-motive sector are exterior mirror hous-ings, radiator grills, centre pillar trims,window frames, cowl vent grills, fairingsand lamp housings. Even relatively largecovering panels are often made fromLuran S.

Coloured Luran S is increasingly usedinstead of metal, coated or painted ABS,or SMC materials for moped, motorscooters and motorcycle fairings. Luran Shas also been successfully used for manyyears in exterior parts of recreationalvehicles and trailers.

The commercial vehicle sector is ofincreasing importance. Draft deflectors,steps, radiator grills and exterior mirrorhousings from Luran S have so far beendeveloped in joint projects. Dashboardsand trim panels made from Luran S havelong been in use in agricultural vehicles.

In the last 15 years, Luran S has captured a large shareof the market for exterior automotive parts. More andmore users choose Luran S because of its superiorproperties and its ability to resist UV radiation. Evenafter long-term weathering, Luran S does not show thegreying typical of even UV-stabilized ABS. Also, Luran Swithstands hot-water treatments such as the removal ofthe wax layer from new vehicles and frequent car wash-es. The cost saving compared with coated or paintedABS provides a further incentive for the change to Luran S.

Luran S has a broad range of applications ...... in automotive construction

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5

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Because of its exceptional UV stability,well-known antenna manufacturers useLuran S for items such as parabolicreflector coverings, mobile antennas, TVantenna parts, cable connection hous-ings, weatherproof protective housingsfor satellite electronics, diplexer housingsand amplifier parts.

Luran S is distinguished by high heatresistance and colour stability combinedwith excellent resistance to oils, fats andother chemicals – properties which meetthe stringent requirements of manu-facturers of washing machine panels,refrigerator handles, mouthwash hous-ings, sewing machines, kitchen appli-ances, grills and microwaves.

For equipment which can experiencesevere mechanical stresses, for examplemobile telephones, the ASA + PC blendsare especially suitable.

A typical application for Luran S, with its resistance to weathering, is antenna construction. Wind and weather subject theexternal elements of antennas to severe attack. Unsuitable materials corrode or become brittle. Luran S is not just an all-weather plastic; it is also the ideal material for heavily used household appliances andlong-lived consumer goods, for example “white goods”.

... in electrical engineering and electronics

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The applications are extensive. Theyrange from surfboards and snowboardsto moped and motorcycle fairings.

... in sport and leisure

Surfboard or sailboat, golf trolley or skibox -Luran S makes sure that you can enjoy yourleisure time. The superior properties of Luran S are seen in improved long-term serviceability. Injection-moulded or extruded,Luran S performs in any weather.

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For example, petrol-poweredlawnmowers require goodmechanical properties, resis-tance to petrol and colourfastness. This is a clear casefor Luran S.

When an outdoor table or aserving trolley has to bescratch-resistant, Luran S notonly gives you a surfacewhich is harder than poly-propylene, but also greaterrigidity with comparabletoughness.

The combination of properties which givesLuran S its success, namely excellent resis-tance to weathering, ageing and yellowing,have been tried and tested for many years ininnumerable applications, both indoors andoutdoors.

... in a wide variety of indoor and outdoor uses

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Luran S and its characteristic properties

Mechanical properties

Stress-strain performanceThe mechanical performance of Luran Sgrades is depicted in Fig. 1 using thestress-strain curve from the tensile test.

Depending on their rubber content theindividual grades show differences in theiryield stresses. The shape of the stress-strain curves also depends on the testtemperature and the strain rate. Fig. 2uses Luran S 778 T to illustrate the tem-perature dependence of strength.

Increasing test temperatures give higherstrain and lower strength values.

The modulus of elasticity also decreaseswith increasing test temperature. How-ever, in the temperature range between –20 and 80°C, relevant in industrial applications, the Luran S grades have ahigh and essentially constant rigidity.

The Luran S range at a glance

Globally available grades

Luran S 757 G:ASA injection moulding grade with high stiffness and flowability

Luran S 776 S:ASA injection moulding grade with enhanced toughness and lower flowability

Luran S 776 SE:ASA extrusion grade with enhanced toughness; especially suited for sheet and profiles with reduced gloss

Luran S 777 K:Easy-flowing, ASA injection moulding grade with good impact resistance

Luran S 778 T:ASA injection moulding grade with increased heatdeflection temperature; especially for automotive parts

Luran S 778 TE: ASA extrusion grade with increased heat deflection temperature and high gloss

Luran S 797 S: ASA injection moulding grade with very high impact strength

Luran S 797 SE: ASA extrusion grade with very high impact strength; especially suited for sheet and profiles with high gloss

Regional products*

Luran S 757 R: ASA with high stiffness and medium flowability

Luran S 796 M: ASA injection moulding grade with high toughness and enhanced flowability

Luran S KR 2858 G3:ASA with 15% glass fibres; high stiffness

Luran S KR 2861/1C:ASA/PC standard grade for injection moulding and extrusion

Luran S KR 2863 C:ASA/PC with very high heat deflection temperature

Luran S KR 2864 C:ASA/PC injection moulding grade with high flowability

Luran S KR 2866 C:ASA/PC grade with lower PC content; lower heat deflection temperature and impact strength

Luran S KR 2867 C WU:Flame retardant ASA/PC with high flowability; free of chlorine, bromine and antimony

*not available in all geographic regions

Luran S is the trade name for BASF’s styrene-acrylonitrile copolymers which are impact-mod-ified with acrylate rubber. The range includesgrades for injection moulding and for extrusion.

Luran S is obtained by copolymerizing styreneand acrylonitrile in combination with an elas-tomeric acrylate-based component. The elas-tomer component is distributed uniformly in theSAN structure in the form of very small parti-cles.

The Luran S grades which have a “C” at the endof their product name are polymer blends ofASA and polycarbonate (eg. Luran S KR 2866 C).

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Shear modulusThe curves for shear modulus and loga-rithmic decrement of mechanical dampingshown in Fig. 3 give insight into themechanical performance of the Luran S grades when undergoing small,periodically changing deformations, as afunction of temperature.

The Luran S grades have a dampingmaximum at about –40°C which can beattributed to the glass transition tempera-ture of the elastomer component. Theelastomer component becomes effectiveabove this point and gives Luran S atoughness which increases as the tem-perature rises.

The shear modulus is almost constantover the temperature range from about–40°C to about 100°C.

Thus, Luran S has high rigidity and excel-lent toughness over a wide temperaturerange.

60

50

40

30

20

10

00 2 4 6 8 10 12

Strain (%)

Stre

ss a

mpl

itude

(M

Pa)

Luran 778 T

Luran 797 S

80

60

40

20

00 1 2 3 4 5

Strain (%)

Tens

ile S

tress

(MPa

)

-40°CY

Y

Y

Y

Y

Y

Y

Y

-20°C

0°C

23°C

40°C

60°C

80°C

100°C

Luran S KR 2863 C, G'

Luran S 778 T, tan �

Luran KR 2863 C, tan �

Luran S 778 T, G'

10000

1000

100

10

1

-50 -30 -10 10 30 50 70 90 110 130 150Temperature (°C)

Shea

r mod

ules

G' (

N/m

m2 ) 102

101

100

10-1

10-2

10-3

Log.

dam

ping

dec

rem

ent t

an �

Fig. 1: Stress-strain curve for various Luran S grades (ISO 527tensile test at 23°C)

Fig. 2:Stress-straincurve of Luran S778 T at differingtemperatures (testwas discontinuedat 10% strain)

Fig. 3: Shearmodulus and log-arithmic decre-ment of mechani-cal damping ofLuran S 778 Tand Luran S KR2863 C (ISO 537torsion pendulumtest)

Impact strengthLuran S combines rigidity, strength anddimensional stability with high toughness.Typical values for the impact strength aregiven in the brochure “Luran S: Features,typical values, applications”.

An assessment of toughness which isvery well correlated with the performanceof plastics in practical applications can beobtained using the penetration testaccording to ISO 6603-2. A bolt impactsthe test specimen (usually an injection-moulded disk) at a velocity of about 4.5m/s, and the penetration energy servesas a measure of the toughness.

Fig. 4 shows the penetration energy mea-sured on 2 mm thick disks (diameter 60mm) as a function of the temperature.While the toughness of Luran S increaseswith increasing temperature the value forthe blends of Luran S with polycarbonate (Luran S KR 2861/1 C), is almost inde-pendent of temperature.

Creep strengthThe mechanical performance of Luran S under continuous static load isshown in the isochronous stress-straincurves (Fig. 5-8). The static load whichcan be withstood is strongly dependenton temperature. The graphs shown hereare merely a selection from our extensivetest results.

80

60

40

20

0-50 -40 -30 -20 -10 0 10 20 30 40 50

Temperature (°C)

Pene

tratio

n en

ergy

(Jou

le)

Luran S 757 G

Luran S KR 2861/1 C

25

20

15

10

5

00 1 2 3 4 5

Strain (%)

Tens

ile s

tress

(MPa

)10 h

100 h 1000 h

10000 h100000 h

15

10

5

00 2 4 6 8 10 12

Strain (%)

Tens

ile s

tress

(MPa

) 10 h 100 h1000 h

10000 h 100000 h

Fig. 4: Penetrationenergy for 2 mmthick disks (diam-eter 60 mm) of Luran S in theISO 6603-2 pene-tration test

Fig. 5: Isochro-nous stress-straincurves for Luran S 778 T at23 °C (ISO 899)

Fig. 6: Isochro-nous stress-straincurves for Luran S778 T at 60 °C(ISO 899)

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Resistance to weathering

Luran S has high resistance to weatheringbecause the elastomer component con-sists of an acrylate having a significantlyhigher resistance to UV radiation andattack by atmospheric oxygen than thebutadiene rubber which is used, forexample, in impact-modified polystyreneand ABS.

A very sensitive method of quantifying thechange in the mechanical properties ofpolymers brought about by the effects ofweathering is to determine the penetrationenergy on weathered specimens. If the(unirradiated) reverse side of the speci-mens is impacted, the irradiated front sideexperiences a sudden tensile stress, sothat even the slightest deterioration givesa clear reduction in the measured values.This test is therefore an excellent indicatorof weathering resistance. In contrast, ifthe impact is on the irradiated side, asmost frequently happens in practice, areduction in toughness is only observedafter much longer exposure times. Mea-surable reductions in the values of proper-ties such as breaking stressand modulus of elasticity arealso seen only at a much laterstage.

Figure 9 shows the penetra-tion energy curve for 2 mmthick disks of ABS and Luran S.While the toughness of ABSfalls away very rapidly, Luran Sremains at a high level for asignificantly longer period. The(ASA+PC)-Blends and UV-sta-bilized Luran S show particu-larly favourable performance.

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25

20

15

10

5

00 0,5 1 1,5 2 2,5 3 3,5 4

Strain (%)

Tens

ile s

tress

(N/m

m2 )

100 h1000 h 10 000 h

50 000 h

16

14

12

10

8

6

4

2

00 0,5 1 1,5 2 2,5 3 3,5 4

Strain (%)

Tens

ile s

tress

(N/m

m2 )

10 h100 h 1 000 h

5 000 h

70

60

50

40

30

20

10

00 500 1000 1500 2000

Hours of sunshine

Pene

tratio

n en

ergy

(Jou

le)

ABS

(PC + ABS)

Luran S KR 2861/1 C

Luran S 778 T

Luran S 778 T UV

ABS-UV

Fig. 7: Isochronous stress-strain curves for Luran S KR 2861/1 C at 23 °C (ISO 899)

Fig. 8: Isochronous stress-strain curves for Luran S KR 2861/1 C at 80 °C (ISO 899)

Fig. 9: Toughness in the ISO 6603-2 penetration test after outdoor weathering in Limburgerhof, Germany; penetration energy on 2 mm thick disks

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The outdoor weathering of plastics maynot only change their mechanical proper-ties. The combination of UV radiation,atmospheric oxygen and heat frequentlycauses a clearly visible yellowing. Also inthis respect, the chemical structure ofLuran S makes it exceptionally stable.

Figure 10 shows the yellowing of differentwhite-coloured plastics on outdoorweathering. All products change colourvery slightly in the early stages. WhereasABS and PC + ABS show rapid yellowingafterwards, Luran S yellows only at amuch later stage and to a much lesserextent. Luran S containing an additionalUV stabilizer shows particularly excellentperformance. Even after 4000 hours ofsunshine, corresponding to more thantwo years of outdoor weathering, thisproduct still shows virtually no yellowing.

The very low level of yellowing of Luran S in outdoor weathering is compa-rable with that of PVC, a material whoseideal suitability for outdoor applicationshas been proven in many years of use.

For applications of Luran S in automotiveexteriors it is particularly important that, incontrast to UV-stabilized ABS and PC +PBT blends, dark-colored formulationshave only a very slight tendency to gray-ing after weathering followed by contactwith hot water or soap solution. This rep-resents the typical conditions both for theremoval of wax from new vehicles afteroutdoor storage and also for vehicleswhich are cleaned after being subjectedto solar radiation.

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30

25

20

15

10

5

0

-50 1000 2000 3000 4000

Hours of sunshineDe

gree

of y

ello

win

g (d

elta

b)

Luran S UV

ABS resp. (ABS + PC)

Luran S (ASA + PC)

Luran S (ASA)

70

60

50

40

30

20

10

00 20 40 60 80 100

Storage time (weeks)

Pene

tratio

n en

ergy

(Jou

le)

Luran S (ASA + PC)

ABS PC + ABS

Luran S (ASA)

80

60

40

20

00 20 40 60 80 100 120Storage time (weeks)

Degr

ee o

f yel

low

ing

Luran S (ASA + PC)

ABS

PC + ABS

Luran S (ASA)

Fig. 10: Yellowing of ABS, Luran S and blends on outdoor weathering (white pigmentation)

Fig. 11: Toughness of ABS, Luran S and blends after heat ageing at 90°CPenetration energy on 2 mm thick disks

Fig. 12: Yellowing of ABS, Luran S and blends (white pigmentation) on heatageing at 90°C

Long-term heat resistance

The stability of Luran S grades to long-term heat exposure can be proven bystorage at, for example, 90°C. Whereasthe mechanical strength of comparableABS products decreases rapidly in thistest, Luran S shows only a small changein toughness over the same period (Fig.11).

Likewise, the resistance to yellowing ofLuran S on exposure to heat is very muchhigher than that of ABS and PC + ABS(see Fig. 12).

Fire performance

Fire performance according to UL 94 andDIN IEC 707/VDE 0304 Part 3, “Testmethods for determining the flammabilityunder the action of igniting sources” isgiven in the brochure “Luran S: Features,typical values, applications”.

Building products made from Luran S aretested according to “Supplement to DIN4102–Fire performance of building materi-als and building components”. Flat sam-ples of Luran S of thickness of 1.0 mmand above are generally rated B2 (“build-ing materials of normal flammability”)according to this standard. Further, theyare normally rated as “not forming burningdroplets”.

For applications in automotive construc-tion, the requirements of MVSS 302and/or DIN 75200 must be met. Flatspecimens of Luran S in thicknesses of1mm and above fulfill these requirements.

Gaseous combustion products ofLuran SIn principle, every combustion processgives rise to toxic substances; carbonmonoxide is the most important of theseand generally has a decisive role.

The combustion products of Luran S con-tain carbon dioxide, carbon monoxideand water as main components, and alsounburnt carbon (soot), acrylonitrile andhydrogen cyanide as the most importantsecondary products.

Toxicological investigations show that thedecomposition products formed at up to400°C are no more toxic than the com-bustion gases formed from wood underthe same conditions. When decomposi-tion takes place at above 500°C, the levelof risk is comparable with that presentedby the combustion of nitrogen-containingnatural products such as wool andleather.

The combustion gases from Luran S arenot particularly corrosive. The formation ofsoot means that smoke is produced inconsiderable amounts.

Flame-retardant Luran SThe flame-retardant product Luran S KR2867 C WU has been developed for partssubject to higher fire protection require-ments. This grade, which contains nochlorine, bromine or antimony, has goodpigmentability, even in pale colours, andexcellent resistance to yellowing. Theproduct achieves the UL 94 V-0 classifi-cation at a thickness of 1.5 mm andpasses the glowing wire test(IEC 695-2-1) at960°C and a thick-ness of 2 mm.

Electrical properties

Luran S has good electrical insulation per-formance. The important parameters arethe volume resistivity and surface resistivi-ty, the dielectric strength, the comparativecracking performance, and the dielectricconstant and dissipation factor (see thebrochure “Luran S: Features, typical val-ues, applications”).

In the electrical supply industry, Luran S is used particularly for protectiveinsulation-housings and covers. In electri-cal communications engineering, Luran Sis used both as a material for housingsand covers and as an actual insulator.

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Permeability to water vapour andgases

Luran S is impermeable to water.Depending on the pressure drop betweenthe inside and outside, water vapour andgases can diffuse through a sheet ofLuran S. Further details are given in Table 1.

The gas permeability also depends on theconditions of manufacture of the films orother finished parts.

In pigmented Luran S, the possible effectof the pigments used must also be takeninto account. For example, certain pig-ments can undergo changes in heavilychlorinated water, and this can cause acolour shift of the parts.

Because such effects vary widely, labora-tory experiments can only give guidelines;it is essential to carry out tests on theactual finished part.

Detailed information can be found in thedata sheet “Chemical Resistance ofStyrene Copolymers”.

Luran S has good resistance to stresscracking; the acrylate rubber in Luran Sgives it a better performance than ABS(Fig. 13).

Because of their polycarbonate content,the (ASA + PC) blends are more suscepti-ble than other Luran S grades to environ-mental stress cracking.

Finished parts made from Luran S do notrequire special care. Scratches can betreated with the majority of commerciallyavailable creams and polishes for paint,leather or wood. Dirt can be removedwith water and soap or detergents.

Antistatic performance

At normal atmospheric humidity levels,finished parts made from Luran S havethe advantage that dust marks do notform on them during manufacture or stor-age or in use. High electrical chargesapplied to the surface of Luran S, forexample by corona discharge, dissipaterapidly.

Resistance to chemicals

At room temperature, Luran S is stable tosaturated hydrocarbons, low-aromaticfuels and mineral oils, vegetable and ani-mal fats and oils, water, aqueous saltsolutions and dilute acids. Although mostLuran S grades are also stable to alkalis,the polycarbonate content of the Luran S(ASA+PC) grades makes them suscepti-ble to damage by alkalis, ammonia andamines.

Concentrated acids, aromatic hydrocar-bons and chlorinated hydrocarbons,esters, ethers and ketones attack Luran S.

The effect of any medium on a plasticarticle depends to a great extent on thetime of exposure and the temperature.The effect is generally amplified if theLuran S part is subject to internal orexternal stresses.

It should also be noted that engineeringmaterials usually contain varying amountsof ancillary ingredients, which can havedifferent effects on stability. 60

50

40

30

20

10

0

Ball oversize in �m

Tens

ile s

treng

th �

B (N

/mm

2 )

Luran S (ASA)

ABS

0 100 200 300 400 500

Medium: isopropanol (1 h)

Fig. 13: Stress cracking performance of Luran S and ABSwith respect to isopropanol, measured by the ISO 4600ball indentation test

1 The values are highly dependent on the conditions of manufacture of the film, and may vary by more than 50% in either direction as a result.

2 Measured according to DIN 53122, relative humidity drop from 85% to 0%, pressure drop 23.87 mbar.3 Measured by a method similar to that of DIN 53380, Part 2 (M).

Table 1: Typical values1 for permeability to water vapour and gases

Luran S-grade Water vapour2 Oxygen3 Nitrogen3 Carbon-g · m-2 · d-1 cm2 · m-2 ·d-1 · bar-1 dioxide3

797 S 35 550 100 2300

Luran S can be processed by any of the processes suitable for thermo-plastics. The most important process-es are injection moulding and extru-sion. Because of its chemical struc-ture, Luran S is relatively stable to thetemperatures encountered in pro-cessing. Even so, unnecessarily longresidence times in the machineshould be avoided, especially if melttemperature is high.

General information

PredryingLuran S granules can absorb smallamounts of moisture from the air duringstorage. Although this does not changethe properties of the product, streaks orbubbles can appear during processing,depending on the moisture content. Wetherefore recommend predrying of Luran Sbefore processing.

The Luran S grades which have a “C” intheir designation (eg. Luran S KR 2861/1C) are blends of ASA and polycarbonate.Since these products are generallyprocessed at melt temperatures which arehigher than those for other products inthe Luran S range, we always recom-mend that they be predried. The dryingtemperature should be about 10–20°Clower than the Vicat softening point(VST/B/50, see “Luran S: Features, typicalvalues, applications”). The drying condi-tions are given in Table 2.

Self-colouring of Luran SSpecial know-how is required for colour-ing Luran S. Compared to other plastics,e.g. ABS, Luran S requires much higherpigment concentrations. Many colourantsand masterbatches are unsuitable due totheir insufficient heat or weathering resis-tance. In addition, unsuitable colourantsor masterbatch ingredients may, overtime, migrate to the surface of the finishedparts or be extracted by the influence ofchemicals (e.g. cleaning agents or sol-vents).

Because of this we do not recommendself-colouring of Luran S. Instead we sug-gest using Luran S coloured by BASF.

Over several decades BASF has devel-oped considerable expertise in thecolouration of Luran S. The colourantsused meet high requirements and havepassed stringent tests in order to beapproved for Luran S. Therefore Luran Scoloured by BASF has excellent weather-ability and heat ageing resistance, and thecolourants are embedded permanently inthe plastic material.

Mechanical RecyclingBecause of its high thermal stability, up to30% of clean Luran S of a single gradeand whose previous processing has notinvolved contamination may be added tothe starting material in the manufacture ofmoldings where this is appropriate. Theusual crushers or granulators can be usedfor size reduction. Regrind should be welldried.

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Processing of Luran S

Table 2:Drying temperature Drying time Acceptable

(°C) (h) moisture contentLuran S (ASA) 80 2–4 < 0.1Luran S (ASA+PC) 90–115* 2–4 < 0.1* = 10–20 °C below Vicat softening point VST/B/50

Table 3: Typical values for screw configurationZone length Flight depth in mmOverall length L 16-20 D D* hE hA

Feed zone LE 0.5 L 30 5 2.5Compression zone LK 0.3 L 50 6 3Metering zone LA 0.2 L 70 8 4D*= Screw diameterhE= Flight depth in the feed zonehA= Flight depth in theMetering zone

An eventual warpage of the moldings canbe counteracted by separate and differen-tiated temperature control of the twohalves of the mold.

The injection moulding processProcessing temperatureLuran S moulding compounds are generally processed at melt temperaturesof from 240 to 280°C, but the poly-carbonate-containing Luran S grades (eg. Luran S KR 2861/1 C) should beprocessed at 260 to 300°C except theflame-retardant grade Luran S KR 2867CWU, for which a temperature range of260 to 280°C is recommended (Table 4).

For processing at the upper end of thetemperature range short residence timesshould be used, since otherwise thematerial can undergo thermal degrada-tion. This can be recognized in colouredcompounds by the change in colour; itnormally becomes somewhat paler.

Injection mouldGate and mould designAny known type of gate may be used,including hot runner systems.

The guidelines for the design of gates andmoulds for the manufacture of injection-moulded parts from thermoplastics (VDI2006) are also applicable to Luran S.Gates and feed channels should not betoo small, otherwise excessively high melttemperature and injection pressure arerequired. This can result in streaks, char-ring caused by shear, voids or sink marks.

Use of insertsMetal parts can be moulded in withoutdifficulty, but they should be preheated to80–120°C before being placed in themould so that no internal stresses are

created. The metal parts mustbe free of grease, and toimprove anchoring shouldhave milled, grooved or similarsurfaces. Metal edges shouldbe well rounded.

Mould temperature controlA carefully designed tempera-ture control system for themould is particularly important,since the effective mould sur-face temperature has a deci-sive effect on surface quality(gloss, flow lines) and on theweld line strength, distortion,shrinkage and tolerances of

mouldings. The recommended mould sur-face temperatures for Luran S grades aregiven in Table 4.

NozzlesOpen nozzles can be used for process-ing Luran S moulding compounds be-cause Luran S melts are relatively vis-cous. Open nozzles have a very simpledesign and therefore give particularlygood flow.

Shut-off nozzles have advantages whenhigh back pressure is being used orundesirable stringing has to be avoidedand thick-walled parts are to be manu-factured.

Mechanically or hydraulically operatedneedle valve nozzles have proven themost successful.

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Table 4Processing Mold Typicaltemperature (°C) temperature (°C) shrinkage (%)

Luran S (ASA) 240-280 °C 40-80 °C 0.4-0.7Luran S (ASA + PC) 260-300 °C 60-90 °C 0.3-0.7Luran S KR 2867 C WU 260-280 °C 40-60 °C 0.3-0.7

Feed characteristicsEven at high screw rotation rates plastifi-cation of Luran S moulding compoundsproceeds smoothly and without thermaldegradation. Plastification performancerises with increasing processing tempera-ture.

It is frequently possible to set the individ-ual heating zones of the cylinder to thesame temperature. For high processingtemperatures and/or for long cycle timesthe temperature of the first heater band(close to the feed hopper) should be setsomewhat lower in order to prevent pre-mature melting of the granules in the feedzone (bridging).

Mould fillingA relatively high injection speed is usefulsince little cooling occurs during mouldfilling; this gives a glossy surface, a lowvisibility of the weld lines and a high weldline strength. Too low a rate of mould fill-ing gives parts with unsatisfactory sur-faces.

When the melt is injected, care should betaken that the air in the mould cavity canescape at a suitable point, to avoid char-ring by compressed air (Diesel effect).

To obtain perfect injection-moulded partsand to prevent the formation of voids, thehold pressure and the hold pressure timemust be sufficient to compensate the vol-ume reduction which occurs when themelt is cooled. On the other hand over-feeding of the mould cavity must also beavoided, since this causes stresses in themoulding. The risk of overfeeding existsmainly in the vicinity of the gate, at highinjection rates and high hold pressure.

Flow characteristicsThe spiral flow test in Figs. 14 and 15shows the flow characteristics of Luran S. Although this test is not coveredby a standard, it gives an assessmentwhich is close to practical experience.

The flowability or the flow distance of aproduct depends not only on the pro-cessing parameters, such as injectionpressure, injection rate, melt temperatureand mould temperature, but also on thedesign of the mould.

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800

700

600

500

400

300

200240 260 280

Melt temperature (°C)

Flow

dis

tanc

e (m

m)

757 G

777 K

796 M

797 S

778 T

KR 2864 C

KR 2863 C

KR 2861/1 C

600

500

400

300

200260 270 280 290 300

Melt temperature (°C)

Spira

l flo

w d

ista

nce

(mm

)

Fig. 14: Flowability of Luran S (ASA) as a function of melt temperature (spiral flow test).Mould: Test spiral 2 mm x 10 mm;Injection pressure: 1100 bar;Mould surface temperature:60 °C

Fig. 15: Flowability of Luran S (ASA + PC) as afunction of melt temperature (spiral flow test).Mould: Test spiral 2 mm x 10 mm;Injection pressure: 1100 bar;Mould surface temperature:80 °C

Blow moulding

The Luran S grades most suitable forblow moulding are those with low flowa-bility.

The parison should be extruded at a melttemperature of from 220 to 230°C. Inindividual cases, the melt temperature canbe lowered to about 210°C in order toreduce stretching of the extruded tube.

In order to avoid a high material tempera-ture resulting from frictional heat, thescrew of extruders with a grooved, cooledand thermally insulated feed zone shouldhave somewhat deeper flights than those,for example, for high-molecular-weightPE-HD.

Short ejection cycles, as achieved whenmelt accumulators are used, are advanta-geous.

Undercuts in blowing moulds, eg. at thethread runout or as a result of the curva-ture of bottle bases, should be avoided.The pinch-off areas can be designed inthe same way as for PE-HD processing.The pinch-off edges should be as sharpas possible to ease flash removal. In thecase of engineering parts, the flash areasshould be sectioned off by well-definedpinch-offs.

Extrusion

Luran S is highly suitable for the extrusionof sheets, solid and hollow profiles andpipes. Specific extrusion grades are avail-able for this and are identified with an “E”(eg. Luran S 797 SE).

Sheet manufactureSuitable extru-ders for the man-ufacture ofextruded sheetscomprise thosegenerally used forprocessingimpact-modifiedpolystyrene andABS, having asheet extrusion

die. Vented extruders with a screw lengthof from 25 to 30 D and a compressionratio of from 1:2 to 1:4 are preferable.

In most cases the optimum throughput of sheets with superior mechanical properties and good appearance isachieved at about 230°C for the Luran S(ASA) grades or at about 260°C for theLuran S (ASA + PC) grades.

Pipe and profile manufactureThe same conditions apply for the manu-facture of pipes and profiles as for theextrusion of sheets. The melt tempera-ture, however, is generally set lower inorder to achieve sufficient melt strengthbetween die and calibrator. The recom-mended lower limit here is 200°C. Prefer-ably, the cooling conditions should be setto give an external temperature of about70 to 80°C for the semifinished productsafter passing through the waterbath.

Mould releaseLuran S can be readily demoulded, sothat even mouldings of complicateddesign are possible. Drafts of from 0.5 to0.9° are generally sufficient.

Textured surfaces require larger drafts: 1°makes it possibleto demould a partwith 0.02 mmdepth of texturefrom the mouldcavity and a partwith 0.01 mmfrom the mouldcore.

Shrinkage andpost-shrinkageShrinkage is sig-nificantly lowerwith Luran Smoulding compounds than with semi-crystalline plastics.

The processing shrinkage is usually from0.4 to 0.7%, and in exceptional caseswell below 0.4%. In regions of a mould-ing which experience high hold pressure(near to the gate) it may even be close to0%.

Post-shrinkage is negligible in most appli-cations, making up about 1/10 of theoverall shrinkage.

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Thermoforming

Sheets and films made from Luran S canbe thermoformed to give mouldings withgood wall thickness distribution. Thermo-forming of Luran S can be carried outwith standard machinery for the vacuumforming and compressed-air forming ofsheets and films. Recommended formingtemperatures are from 140 to 170°C.

Storage and packing of thermo-forming sheetLike ABS, Luran S tends to absorb mois-ture under poor conditions of storage. On thermoforming, sheets which havebecome moist can generate bubbleswhich make the moulding unusable.

Storage in dry areas (about 20°C, 30%relative humidity) prevents the absorptionof moisture which impairs thermoforming.However, if storage takes place understandard conditions of temperature andpressure (DIN 50014-23/50-2), the mois-ture content may reach levels which couldadversely affect processing after somedays or weeks.

Under standard conditions of temperatureand pressure, the final moisture absorp-tion value is about 0.4%, and it isachieved after about 20 days in the caseof 1.5 mm thick sheets. Even a moisturecontent of from 0.05 to 0.1% can, how-ever, impair the surface of mouldings.Wrapping in welded polyethylene film ofadequate thickness, ie. at least 100 µm,provides effective protection against theabsorption of moisture. This special pack-ing greatly delays the absorption of mois-ture, but does not prevent it entirely. Evenspecially packed Luran S sheets shouldtherefore be stored under dry conditions.

Machining and post-processing

MachiningSemifinished products made from Luran Sare easy to machine, ie. die-punch, saw,drill, mill, turn etc., using conventionalmetal- and woodworking machinery.

Tools used for machining brass andbronze are suitable. Because heat dissi-pation is slow, water cooling is frequentlynecessary even at low cutting speeds.Luran S parts can be stamped andflanged without difficulty and can be fas-tened using self-tapping screws.

AssemblyWeldingHot-plate and spin welding are suitablefor welding semifinished products andmouldings made from Luran S, and inspecific cases high-frequency and ultra-sonic welding can also be used.

Ultrasonic welding can also be used toconnect Luran S to a number of otherthermoplastics, such as SAN, ABS, PVCand PMMA.

Adhesive bondingExamples of solvents suitable for adhesivebonding are methyl ethyl ketone, dichloro-ethylene and cyclohexanone. Parts madefrom different grades of Luran S may bebonded to one another, and furthermoreparts made from Luran S may be bond-ed to parts made from ABS or SAN.

For more information we recommendcontacting the adhesives industry, whichoffers a wide variety of suitable specialadhesives.

Surface treatmentParts made from Luran S may be easilyand permanently printed, coated or paint-ed without any special pretreatment. Theycan also be metallized by the metallizingprocesses commonly used in industry.

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No substances which can damage theozone layer (ODC) of Class I (CFC/Halons)or Class II (HCFC) are used as startingmaterials or additives in the manufactureof Luran S.

Luran S in the medical sectorBASF does not carry out product devel-opments for applications in medical prod-ucts (including packaging) as defined bythe German Medical Product Act. Wetherefore have no in-house experience ofthe suitability of Luran S in applications ofthis type and, as a result, BASF is unableto make any product recommendationsfor this section.

For coloured materials the Rec-ommendation IX “Colorants forpigmentation of plastics and other

polymers for consumer goods” of theGerman Federal Health Office should

be taken into account.

The suitability of consumer goods in anyparticular instance should be tested bythe manufacturer or by the user with ref-erence to the maximum permissible

migration values which are establishedby law:

Acrylonitrile: SML = not detectable (detection limit = 0.02 mg/kg)Bisphenol A: SML = 3 mg/kgPhosgene: QM = 1 mg/kg

(SML = specific migration limit in foods orfood simulants; QM = maximum allowableresidual content of the substance in theconsumer good)

In cases where Luran S is to be used incontact with foodstuffs, we will be happyto provide more detailed information andconfirmation regarding compliance withregulatory requirements.

Safety information

Safety precautions during processingNo adverse effects on the healthof processing personnel havebeen observed when process-ing of the products is carriedout correctly and there issuitable ventilation of theproduction areas. Themaximum allowable con-centrations (MAC) of 20ml/m3 for styrene, 100ml/m3 for �-methyl-styrene, 10 ml/m3 for butylacrylate and the technicalreference concentrationof 3 ml/m3 for acrylonitrilemust be observed (GermanHazardous Materials Regulations900; MAC list 1999). Acrylonitrile is aGroup III, A2 substance for which car-cinogenic activity is assumed as a resultof toxicity testing. Experience has shownthat when Luran S is processed correctlywith appropriate ventilation, the levels arefar below the limits mentioned above.Inhalation of the vapours of degradationproducts which can arise on severe over-heating of the materials or during pump-ing out should be avoided. Our safetydata sheets give further information.

Food regulationsMost Luran S formulations fulfill therequirements of the German ConsumerGoods Regulations of 23.12.97 and ofRecommendation VI “Styrene polymers,copolymers and graft polymers” andRecommendation XI “Polycarbonates” ofthe German Federal Health Office as at01.06.98.

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Luran S and the environment

Waste disposalIn Germany, Luran S waste is classifiedunder Waste Code No. 57108 (poly-styrene wastes), except for the Luran S(ASA + PC) grades, which contain poly-carbonate and are classified under WasteCode 57117.

Under German waste monitoring regula-tions, solidified plastic waste of this typedoes not require any special disposalmeasures. Luran S waste can thereforeusually be disposed of to landfill (cf. Safe-ty Data Sheet). According to our knowl-edge, Luran S waste is inert in landfill.Luran S is classified as presenting nothreat to ground water.

Subject to official regulations Luran S mayalso be incinerated in a suitable incinera-tor, eg. a household waste incinerator.The fuel value of Luran S is about 10kWh/kg, about 70% higher than that ofdry wood. Complete combustion givescarbon dioxide, water and nitrogen, thenitrogen being oxidized to a limited extentto give nitrogen oxides.

RecoveryWaste consisting solely of Luran S can berecycled. Waste arising during injectionmoulding or thermoforming, for example,can be fed back to the process as regrind(cf. mechanical Recycling, page 19). Usedparts consisting solely of Luran S can alsobe recycled, after cleaning and sizereduction, to give new mouldings.Depending on the age and application ofthe used parts to be mechanically recy-cled, certain properties, such as mechani-cal properties, colour etc., may haveundergone change; it is therefore neces-sary to check the suitability of the recy-cled material for the intended applicationin each individual case.

The good compatibility of Luran S withABS also makes it possible to include alimited quantity of Luran S in the process-ing of ABS (up to about 25% of Luran S,based on ABS).

It should be noted that, under Underwrit-ers Laboratories (UL) regulations, theflame-retardant grade Luran S KR 2867 CWU does not retain its UL material classi-fication when more than 25% of regrindor recycled material is added.

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Literature references

BASF publications“Chemical Resistance of Styrene Copolymers” (TI-KTC/A 01 d 82 442 July 1995)

“BASF Plastics: Automotive construction”B 569

“BASF Plastics: Electrical engineering” B 570

Other literature“Design of thermoplastic injection mold-ings” VDI 2006

G. Lindenschmidt, R. Theysohn: “Styrenecopolymers (SAN, ABS, ASA)” Kunststoffe, 77 (1987), p. 982

K. Ruppmich: “ASA/PC - An interestingalternative to ABS/PC” Kunststoffe, 75 (1985), p. 740

B. Rosenau: “ASA plastics: Propertiesand applications”Kunststoffe, 85 (1995), p. 804

A. Zahn: “ASA and ABS compared”Kunststoffe, 87 (1997), p. 314

BASF DiskettesCampus

Download: http://www.basf.de/en/produkte/kstoffe/kstoffe/werkst/campus.htm

Internet: http://www.basf.de

Besides advising on measures toincrease the security of supply over theentire supply chain, our specialists canalso help with packing, transport andstorage problems. We can collaborate aspartners to offer help and solutions onany question which may arise.

Cooperation from order booking to deliv-ery brings the supplier and customeradvantages which are well worth having.

26

Supply

Product quality alone is no longer anyguarantee of success in the market. Weoffer our customers tailored supplyarrangements so that they can achievesuccess in the marketing of their prod-ucts. Our professional advice and cus-tomer care ensure that service and costsare kept in balance, from recognizingcustomer requirements at order place-ment, production, storage and distribu-tion through the receipt and use of ourproducts. We can help in finding the rightmethods for reducing raw materialsinventory or achieving service level tar-gets. Special measures can often befound to make shipments quicker andmore flexible. We will help you optimizecost-value ratios.

When the customer examines the wholeof the supply chain, certain questionsalways arise: In which situations doesfast and flexible delivery really make

sense? What are the consequences forcosts in the overall supply chain? What isan acceptable level for raw materialinventory costs? What degree of deliveryreliability is necessary to allow a continu-ing reduction in inventories?

Supply and literature references

27

Plastics from BASF

The product range at a glance

NoteThe information submitted in this publication is based on our current knowl-edge and experience. In view of the manyfactors that may affect processing andapplication, this data does not relieveprocessors of the responsibility of carryingout their own tests and experiments; neither do they imply any legally bindingassurance of certain properties or of suitability for a specific purpose. It is theresponsibility of those to whom we supplyour products to ensure that any propri-etary rights and existing laws and legisla-tion are observed.

Further Information:www.basf.comwww.basf.de

Additional information

on polyurethanes can befound at:www.elastogran.de

on polyolefines can befound at:www.basell.com

on PVC and PVDC can be found at:www.solvay.com and www.solvay.de

Products from BASF AktiengesellschaftTerluran® Acrylonitrile/butadiene/styrene polymer ABS

Ronfalin® Acrylonitrile/butadiene/styrene polymer ABS

Luran® S Acrylonitrile/styrene/acrylate polymer ASA, (ASA + PC)

Luran® Styrene/acrylonitrile copolymer SAN

Terlux® Methyl methacrylate/acrylonitrile/butadiene/ MABSstyrene polymer

Terblend® N Acrylonitrile/butadiene/styrene polymer and polyamide ABS + PA

Luranyl® Blend of polyphenylene ether and PS-I (PPE + PS-I)

Polystyrol, impact-modified Styrene/butadiene polymer PS-I

Polystyrol, impact modified Polystyrene PS

Styrolux® Styrene/butadiene block copolymer SBS

Styroblend® Blend based on styrene/butadiene polymer PS-I blend

Styroflex® Styrene/butadiene block copolymer SBS

Ecoflex® Biodegradable plastic/polyester

Ultradur® Polybutylene terephthalate PBT, (PBT + ASA)

Ultraform® Polyoxymethylene POM

Ultramid® Polyamides PA 6, 66, 6/66, 6/6T

Ultrason® E Polyethersulfone PES

Ultrason® S Polysulfone PSU

Styropor® Expandable polystyrene EPS

Neopor® Expandable polystyrene EPS

Styrodur® C Extruded rigid polystyrene foam XPS

Neopolen® P Polypropylene foam EPP

Neopolen® E Polyethylene foam EPE

Basotect® Foam from melamine resin MF

Palusol® Silicate foam® = reg. trademark of BASF Aktiengesellschaft

PolyurethanesLupranat® Diisocyanates PU

Lupraphen® Polyester polyols PU

Lupranol® Polyether polyols PU

Pluracol®* Polyether polyols PU

Elastan® Systems for sportsfield coverings PU

Elastocoat® C systems as coating and casting compounds PU

Elastoflex® Soft polyurethane foam systems PU

Elastofoam® Soft integral polyurethane foam systems PU

Elastolit® Rigid integral polyurethane foam systems PUand RIM systems

Elastonat® Flexible integral polyurethane systems PU

Elastopan® Polyurethane shoe foam systems PU

Elastopor® Rigid polyurethane foam systems PU

Elasturan® Systems as cold curing cast elastomers PU

SPS® Steel-polyurethane systems PU

Elastospray PU system PU

Autofroth® PU system PU

ElastoskinTM* Flexible integral polyurethane systems PU

Cellasto® Components made from microcellular PUR elastomers PU

Elastocell® Components made from microcellular PUR elastomers PU

CeoDS® Multifunctional composits made from Cellasto® components PU

Emdicell® Components made from microcellular PUR elastomers PU

Elastollan® Thermoplastic polyurethane elastomers TPU ® = reg. trademark of Elastogran GmbH®* resp. TM* = reg. trademark of BASF Corporation

BASF Aktiengesellschaft67056 LudwigshafenGermany

KTC

LS 0

001

B e

01.

2001

Do you have technicalquestions about styrenecopolymers?

We will be happy to answeryour questions at our Copoinformation point:

Internet: www.basf.de

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