Abs and Sans Processing in India

8/2/2019 Abs and Sans Processing in India

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EXECUTIVE SUMMARYINTRODUCTIONBoth ABS (Acrylonitrile-Butadiene-Styrene) and SAN (Styrene-Acryloni-trile) are versatile engineering thermoplastics, which have replaced manytraditional m aterials of cons truction like wood, glass, me tal, rubbe r e tc. inmany applications. Th ese polym ers can be easily tailored for specific us esthrough co-polymerising, blending, alloying and changing polymerstructure.Of late, with the advent of various speciality and advanced therm opla sticssuch as POM, PA, PBT, PET, PPO, etc. the impo rtance of ABS, SAN, as anindispensible engineering thermoplastic, has been slightly reduced. To-day, they are vised in low performa nce applications. Their bulk consu m p-tion in conventional applications has also reduced due to interpolymercompetition from cheaper commodity plastics.Thou gh know n to exist since 1930s, these polymers we re first intro du cedfor industrial applications in 1950s in U.S.A. Now, the se polym ers ar econsum ed in significant quan tities (especially ABS).PROPERTIESAs ABS and SAN are com posed of various bu ilding blocks (e.g. Butad iene ,Acrylonitrile and Styrene in ABS and Styrene and Acrylonitrile in SAN),various combination of properties can be available by varying composi-tion of these monomers. The properties offered by various monomershave been described here below:Monomer Propei~tiesButadiene 1. Impact resistance2. Toughness3. Low temperature

property retentionAc rylon itrile 1. Chemical resistance2. Meat stability3- Aging resistanceStyrene 1. Rigid ity2. High gloss3- Ease in processing

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The comparative p rope rties of ABS and SAN v /s . major them oplasticshave been given in the following table.COMPARATIVE PROPERTIES OF ABS, SAN V/S. OTHERMAJOR PLASTICS

ABSSA NPSH D P EP P

SpecificGr av i ty

1.01-1.051.07-1.08

1.040.960.90

Vicat Softe-ning PointC

100-11070-9074-105130-137160-168

TensileStrengthp.s.i

310-490700-840360-520220-310310-420

Izodimp ac tf t . lb /inch

10-5012-182-1222-6

C o m p r e s s i v eStreng thp.s. i

490-700-

910-1100190-250240-560

AP P LICATIONSABS may be processed into end prod ucts by m ost thermoplastic process-ing methods such as injection and compression moulding, extrusion,blow moulding an d calendering. Other ope rations such as vacuum form-ing, vapour metallizing, plating, hot stamping and painting may also becarried out.Different grades of ABS are available inter-nationally. Gradewise applica-tions of ABS have be en dep icted in the following table .

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ABS : GRADEWISE APPLICATIONSSr. Grad e Ap plicationsNo.1. High Impact Gra des Travelling bags, Helm ets, Furn iture, SportsGoods, Automotive Components2. Medium Impac t G rades Radiator and Air Co nd ition er grills, Heavyduty domestic appliances, Control panels3. Electroplating Gra des TV and Radio kno bs, Ba throom fittings, Re-frigerator han dles, Name p lates, W heel caps,Clockrings, Canopies, Flash guns, Torch lightsetc.4. High Flow Grad es Housing for dom estic appliances and officeequipments, Cabinets of TVs, Radios, Wallclocks, Tape recorders and Car stereos.5. High Heat Resistant Grades A uto m ob ile c o m po n en ts , H ou sin g forelectrictrical h eate rs & Dryers.6. Transparent Grades Used in areas wh ere high transparency &good impact strength is requ ired.7. Impact Modifier Grad es Modifier to PVC com pou ndin g industry, cov-ering all types of formulations-rigid, semi-flexible, clear and opaque.8. Glass Filled Gra des Used in applications requ iring a very highflexural strength, stiffness, maintaining theimpact and tensile properties.9. Extrusion Gra des Refrigerator linings and luggages

Note-.SeveralABS alloyssuch asABS/PCandABS/PVCare alsobeingnsedinmanyareas.

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Applications of SAN are listed below :Sr. ApplicationsNo. Articles

a) Houseware

b) Appliances

c) PackagingIndustrial

brush blocks and handles, broom and b rush bristles,cocktail glasses, disposable dining u tensils, hange rs,ice buck ets, jars,mugs, soap c ontainers and tum bler s.air conditioner parts, dec orated escutcheo ns, washerand dryer instrument panels, washing machine filterbowls, refrige-rator shelves and crisper pans, b lend-ers, mixers,lenses, knobs and covers.bottles, closures, containers, display box es and films

d) Automotive batterie s, business machines, apparatus and equ ipm ent, andtape reels.e) General (custommolding) batteries, bezels, lenses, signals, and interior trim,aerosol nozzles, bottle sprayers, camera parts, den-tures, pen and pencil barrels, sporting goods, toystelephone parts, filter blows, tape dispensers, termi-nal boxes, etc.Note : SANresinsarealsoiisedformakingABSresins. G?xijiedbutadiene latexis blendedin a matrix of SANresins toproducefinalABS products.4 ABS MANUFACTURING PROCESSES

ABS is manufactured by three different polymerization pro cesse s viz.,emulsion, suspension and mass process. Historically, emulsion and sus-pension pro cesses have dom inated the field, bu t recently continuou s an dmass process has achieved commercial importance due to its simplicityand improved ru bb er handling in the system.Since bulk proc ess do es no t involve process water, it consum es less energyper kg of product as dewatering and drying steps are eliminated. How-ever, the process has greater mechanical complexity and low conversionratio requ iring devolatization step for removal of residua l mo no m ersprior to compounding of the final product.

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ABS resins are m anufactured using styrene acrylonitrile co polym er dis-perse d in rub ber latex which can be either po lybutadiene (PB), styrenebuta dien e rub ber (SBR) or nitrile butadien e ru bb er (NBR). Other rub be rsystems such as ethylene propylene diene rubbers (EPDM) are alsoknown to be used for special polymers such as AES, but are relativelyuncom mon. Most commercial processes use a polybu tadiene ru bb er latexfor production of ABS. Besides, several other chemicals such as emulsifi-ers, suspending agents, initiators, chain transfer agents, additives andstabilizers are involved dep end ing on the proc ess used and gra de of ABS.Originally the elastom ers w ere mechanically bl en de d with rigid SANcopolymers, but now grafting technique is widely used to produce ABSresins. This is do ne to overcome the incompatibility betw een the rub be rparticles and rigid copolymer matrix which caused the dispersion to benon-uniform and resulting in und esirable physical pro pe rties . Th e d eg reeof grafting depends on the concentration of monomer, mercaptan (MWregulator), surfactant, monomer/ rubber ratio and polymerisation tem-peratures.SAN MANUFACTURING PROCESSESSAN copolymers are commercially produced as in the ABS process byemulsion, suspension and bulk processes. Amongst the various pro-cesses, emulsion process is quite popular but has the disadvantage ofgreater haze due to presence of emulsifying agents. Of late, continuousbulk polymerization has be com e po pula r and is normally us ed for. makingm ould ing gra de SAN resin. Specifie features of various pro ces ses aredesc ribed in the following table.

Sr. Process Specific FeaturesNo.1. Emulsion Process * Uses emulsifying age nts like dodec yl ben -zene sulfonate, polyorganosiliozanes andpolyethylene oxide grafted with maleic anhy-dride and vinyl acetate.

* This proc ess involves consid erable -water pol-lution haza rds as mo no m ers (especially ACN)are partially soluble in water.

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Sr. Process Specific Feature sNo.* The mo nom er conversion in emulsion pro-cess are veiy high (97%) as compared to66.5% in continuous bulk process.

2. Continuo us bulk process * Does not involve any emulsifiers, susp end -ing agents or water and hen ce n o waste treat-ment and environmental problems* Consum es less energy* efficient space and time utilization* Product has good transparency, lustre, melt

flow propertiesAES MANUFACTURING PROCESSAES is '' .,.-'"-ictured by th ree po lymerisation processes viz., em ulsio n,susp


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Si".N o.

1.

2 .

3.

4.

5.

6 .

7.

C o m p a n y

Synthetics andChemicals l id .ABS Plastics Ltd.

Polychcm Ltd.

Gujarat BinilChemicals Ltd.Bhansali Engi-neer ing PolymersLtd.GSFC

Poly Raj.

P r o d u c t

A B S

ABS

SA N

ABS

SA NA B S /S A N / H I P SA B S

S A N

S A N

Year ofStar t -up

1978

1978

1979

19901986

1990

1982

-

Locat ion

Bareilly

Baroda

Baroda

Anka lesh -w arM.P .

Baroda

Vap i

ProcessKnow-how

SRI I R/N R D CSRI I R/NRDC andJ a p a nSynthet icRubberSRI I R/N R D CP e n m a n a ,U.K.

In house

S u m i t o m o

I nhouse

-

C a p a c i t yM t / Y r .

PilotScale10,000

5000

30002200

7500

30 0

-

C a p a c i t yExpans ionPlanned &Schedu led

20,000 TPAABS-19925000 TPA

20000 TPA

5000 TPA

Plant isshu t down-

9 Altho ugh pr es en t installed capacity is qu ite large, th e total, es tim ate davailability of ABS resins (including im por ts which are m ino r) is only12,000 -13,00 0 MT in 1990-91. In the year 1989-90 the total c ons um ptio nof ABS in India was about 9,000 MT.10 In ord er to m ee t the long term req uir em en ts of ABS and SAN in thecountry, Government has issued several Letters of Intent to Indian

com panie s. These include projects of Indo Nippon, ABS Plastics, H industanPolymers, Suprem e Industr ies, RIICO etc . Out of the se only Ind o Nip ponand ABS Plastics projects are sche dule d to be im ple m ent ed w ithin th e 8thplan pe rio d. T hes e inc lude 5000 tpa of ABS and 5000 tpa of SAN for In doNippon and 5000 tpa of SAN for ABS Plastics. Polychem has commis-sioned a plant to manufacture 3000 TPA of SAN in March 1990.

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240002700029000

350004900046000

12. DEMAND SUPPLY SCENARIOBased on various projections made by different agencies regarding de-man d for ABS by 2000 A.D. and the estimated supply taking into consid-eration various expansion plans and new projects, the demand-supply islikely to be as given below :

ABS : DEMAND SUPPLY GAP(Quantity in tonne)

_ _ _ _ ^ _ _ 1990-91 1994-95 1999-2000Estim ated Supply 13300 31350 43300Estimated Demand

C.P.PC.E.WConsultants 14000

Demand Supply GapC.P.P demandC.E.W demandConsultants 700

C.P.P.- CommitteeforPeispectivePlanningonPetrochemicalsC.E.W.- ChemicalEngineeringWorld,Issue* Basedon 10%CARGover1994-95demand estimates byConsultants

No sep arate dem and projections for SAN copolym ers are available as theindu stry is still in infant stage. Not mu ch produ ctio n of com mercialsignificance is there and demand is likely to build up only when rawmaterials are available indigenously. It is estimated that a demand ofaro un d 4000-5000 MT wo uld b e the re by 1994-95, for m erch ant sale. Thiscan be adequately met by Polychem, ABS Plastics and Indo Nippon SANproject.(ix)

( 7 3 5 0 )( 4 3 5 0 )

( 2 3 5 0 )

( 8 3 0 0 )5 7 0 0

( 2 7 0 0 )


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Gu jarat Sta te F ertiliz er Co . Ltd., B aro da : GSFC's SAN plant was set upbased on in-house R&D effort. It is a small plant using suspension batchprocess set up mainly for scale up study and to produce material formarket study. Operations have been discontinued since last 3-4 years asthe plant o peration s we re unecon omical. Basically GSFC w ere unab le toscale up th e bench scale process and faced seve re operationa l and qualityproblems in the actual plant.Recently Polyraj has set up a plant near Vapi to manufacture SAN.

14 INTERNATIONAL SCENA RIOABS is the sixth largest consumed thermoplastic material in the world.1990 consu mp tion ofABS resins was estimated to b e be tw een 2-2.5 milliontons. SAN copo lym ers are relatively consu m ed in small am ou nts an d 1990consu mp tion w orldwid e is estimated to be 0.2 m illion tons. Major pro duc -ers in this industry secto r a re Dow Chemicals, Monsanto, GE Plastics, JSR,BASF, Mitsubishi etc. The consumption of ABS and SAN of late, hasstagnated and not many plants are coming up as is observed in othercommodity and high perfoimance engineering plastics.Con sump tion of ABS resins in advanced coun tries such as USA, Jap an,Canada and those of Western Europe is as shown below :

SALES OF ABS V/S OTHER POLYMERS - 1990('000 tonn e)

USAW. EuropeJapanCan ad a

ABS

55150160 7

63

LDPE

4941524516721254

H D P E

387029371113394

P P

370036852080

263

PVC

423051582003

45 7

PS

233717921183

184

ModemPlasticsInternational-Janiiaryl991Issue(3d)


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15 Study of consum ption pattern in the West European countries indicatesthat ABS is most widely use d in automotive com pon ent sector. Th e s hareof various secto rs is as follows :Automotive 26%Appliances 18%Electrical and Electronic Sec tor 18%Recreational items 7%Furniture 2%Pipes and Fittings 2%Others 27%SAN finds applications in appliances, autom otive com pon ents, batterie s,compounding, housewares, molded packaging good etc. One majorapplication for SAN is for blending it with grafted ABS resins.

16 The large pro du cer s of ABS and SAN resins normally use con tinuo usmass polymerisation pro cess. In case of ABS variations of mass proc essare also used. These include mass-suspension and mass-emulsion pro-cess. Solution process is used only for special grades and is gettingoutdated. For small size ABS plant, emulsion batch process is ideallysuited and is ado pted by leading Japane se p rod uce rs like JSR, Sumitomoetc. For SAN batch susp ension and c ontinuo us bulk p roces ses are no r-mally used.

17 Amongst various ABS processe s, emulsion and con tinuo us bulk polymer-ization are quite popular. Emulsion process offers wide variety of prod-ucts, high rubber content grades and superior conversion efficiency.Con tinuous bu lk is pop ular be cause of its low cost of pro du ctio n a nd lowinvestment costs. Normally this process is favoured for large size plants.Since water is not used, pollution hazards in this process are minimal.However, this process takes longer time in achieving steady state andconsiderab le off-grade m aterial is pro du ced during g rade chan ge over, orplant shut downs. Relatively, the other ABS processes viz. solution andsuspension processes are less popular.

18 In SAN proc esses, again emulsion and bulk proce sses pre do m ina te.Emulsion an d suspension SAN proces ses have very high conv ersion rateof 99.5% as com pared to 60-70% in bulk process. How ever, du e to pres enc e(xii)


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20 Th e NRDC pro ces s was actually dev elo ped by Shriram Inst i tu te forIndustr ial Research at Delhi in la te 1960s. Th e proce ss wa s dev elo pe d forgenera l purpose mould ing grade , ex t rus ion grade , e lec t rop la t ing g radeand gra de for impact modif ier for PVC. This pro ces s is ba sed on batchem ulsion p olyme rizat ion pro ces s in which ABS is pr od uc ed by graf tingacrylonitr i le and styrene onto PB or SBR latex. Conversions are usuallyaround 90% and reaction batch cycle between 15-18 hrs.

21 IIP pro ces s for SAN copo lym ers is bas ed on sus pen sion batch pro ces s.Since this process has not been commercial ly adopted, i ts performancecann ot be ascer tained . This proc ess also is a ben ch scale proce ss a nd is t r iedonly in a small 30 litre capacity glass lined rea cto r. B atch es of 10 kgs. havebeen ob ta ined and samples were d is t r ibu ted fo r marke t assessment . Butsti ll , th is proc ess was not ad op ted and c ontin ues to remain largely untr ie d.22 TECHNOLOGY ABSORPTION EFFORTS IN INDIA

Several effor ts have been put in by Indian manufacturers in absorbingind igenous as wel l as impor ted knowhow :Two of the Indian ABS manufacturers (Polychem and ABS Plastics)have be en involved in scaling u p a ben ch scale proc ess into com me r-cial size plant . This involved tremendous effor ts on their par t bothfor p rocess deve lopment and des ign of equ ipments .Capac i ty expansion by ex is t ing p roducers based on impor tedk n o wh o w h as b een smo o th b ecau se o f p r o d u ce r s ' p a s t ex p e r t i sebuil t u p in ABS industry . By im port of kno w-h ow the y have be enable to get State-of-the-Art technology.The se two produ cer s have bee n ab le to considerab ly red uc e cos t o fexpan sion of their ABS plants. Foreign exch ange ou tgo also wasminimal as they were able to indigenously procure most of thecapital goods.Through ind igenous R & D effor ts , pro du ce rs have be en able tosuccessfully absorb imported know-how for manufactur ing newgrades o f ABS. These include heat resistant , h igh f low, high impactand electroplat ing grades. Using special addit ive packages, gradeshaving UV resistance an d antistat ic pro per t ies are also p ro du ce d.Ind igenous vendor development ac t iv i ty has been prominen t wi thsome manufac turers . Number o f equ ipments a re ob ta ined f romwithin the country .

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23 TECHNOLOGY GAPSAlthough the ABS industry is now more than a decade old, significanttechnology gaps still exist. These are :

The process used domestically are comparable with the processesavailable abroad, but the indigenous process has poor yield and theproduct has low surface gloss and poor impact strength.Only emulsion batch polymerization process has been adopted inIndia. One plant using continuous bulk process is there, but it is ofveiy low capacity.Technology import dependence is likely to continue as developmentefforts in this area are lacking after having been initially started bySRIIR.Scale of operations are very small as compared to plant sizes abroad.New polymer materials such as ABS polymers using differentrubber latexes such as SBR, NBR and EPDM rubbers are not madein India. Overall grade availability is largely restricted to commoditygrades. New grades for speciality applications are being introduced.ABS blends and alloy industry is not developed. ABS manufacturersthemselves have not put in required efforts for this development,though there exists a good potential for this.Manufacturers of ABS should tiy to tap overseas market.Import dependence on capital goods and automation systems re-main to some extent.Cost of ABS products in India is almost twice the internationalprices, mainly due to lack of economy of scale of production and highcost of raw materials. Capacity utilisation is also low, as raw mate-rials are not readily available from indigenous sources.

24 In case of SAN, there is not even a single plant of commercial significance.Operations in two small scale plants are discontinued. Initial producttrials in these plants were not well received in the market due to pooroptical clarity. Again in this industry too, only suspension batch process

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Abs and Sans Processing in India

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