Melissa Styrochem

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    StyroChem

    Expansion of Expandable

    Polystyrene (EPS)

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    StyroChem

    Expansion Basics Heat Is Applied

    Beads Expand

    Beads Cool Beads Age

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    Expansion - Behind the Scenes Heat Is Applied

    Blo!ing agent(s)

    "apori#es($%oC iso-pentane& 'oC noral-

    pentane& *+oC cyclo-pentane)

    Blo!ing agent(s)

    pereate thro,gh the

    polyer(n-pentanei-pentanec-pentane)

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    StyroChem

    Expansion - Behind the Scenes Beads Expand

    Polyer.blo!ing agent atrix reaches it/s glass

    transition teperat,re (0g)(abo,t %oC& "aries according to 1! 2 BA type)

    Polyer chains becoe fl,id

    Internal press,re created by blo!ing agent

    "apori#ation p,sh apart 3,nfold4 polyer chains&creating cells

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    Expansion - Behind the Scenes

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    StyroChem

    Expansion - Behind the Scenes Beads Expand (cont5)

    Air 2 stea pereate

    into the beads

    As expansion contin,es&

    cell !alls becoe thin

    and s,b6ection to high

    heat can ca,se the tobrea7 and r,pt,re

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    Expansion - Behind the Scenes Beads Expand (cont5)

    0hro,gho,t expansion& blo!ing agent(s)

    contin,e(s) to pereate o,t of the bead at an

    increasing rate 3depending on teperat,re andthic7ness of cell !alls4

    (8hen pereation rate 9.: "apori#ation rate& expansion ceases)

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    StyroChem Expansion of EPS(Endotherms, Expansion Rate, & Pentane Loss)

    25 50 75 100 125 150

    Temperature, C

    EndoExo

    vs!"#esh

    $%ass

    0

    1

    2

    3

    4

    5

    6

    7

    &'()e

    i*ht

    Differential Thermal Analysis Change in Volume n-Pentane oss

    1 !C

    5"

    10"

    15"

    +

    C

    #lo$ing agents

    %egin to &a'ori(e

    Polymer)%lo$ingagent matri* rea+hes

    its TgCell $alls %egin to

    ru'ture

    ,*'ansion

    %egins after

    rea+hing Tg an-'ro+ee-s ra'i-ly

    oss of %lo$ingagent %e+omes

    more ra'i- as

    tem'erature

    in+reases

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    StyroChem

    Priary Expansion Controls 0eperat,re

    0ie

    Time or Temperature

    -ensit(

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    0eperat,re Affects ;reater the teperat,re

    Softer the polyer

    Increased expansion rate

    1ay res,lt in ,ne"en expansion d,e to inconsistent

    pentane content

    bead si#e

    cell str,ct,re

    ra! aterial

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    StyroChem

    Expansion "erses 0eperat,re >??oC

    Expansion can be sl,ggish d,e to stiff polyer

    :>$?oC

    Polyer is too soft& blo!ing agent loss is too rapid

    >>?->$?oC 1ost efficient ,se of blo!ing agent& b,t beads becoe sensiti"e

    to shrin7age and heat

    >??->>?oC@ Best coproise

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    StyroChem

    Stea ,ality ey to Expansion

    Consistent ,tilities are cr,cial to achie"e consistent

    densities !ith consistent "olatile content

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    Secondary Expansion Controls ol,e of Expander

    1olec,lar 8eight

    Blo!ing Agent Bead Si#e

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    Expander ol,e

    Affects the total heat a"ailable to each bead

    0hings that can change it

    Drop.charge !eight

    ,ps in expander that don/t discharge

    B,ild ,p on !alls or stir blades

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    1olec,lar 8eight 0he lo!er the olec,lar !eight&

    Increased expandability

    Increased heat sensiti"ity

    Increased pereation rate of blo!ing agent

    Increased shrin7age

    Increased collapse

    Str,ct,ral strength

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    StyroChem

    Blo!ing Agent Ao,nt

    Higher percentages gi"e greater expandability (to a

    point)

    0oo high a percentage ca,ses rapid pereation

    th,s shrin7age& collapse and heat sensiti"ity

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    StyroChem

    Blo!ing Agent 0ype

    0he longer the blo!ing agent stays in the bead&

    Increased expandability

    Fed,ced shrin7age rate

    Increased prep,ff life (fro expansion to old)

    Felati"e retention

    n-pentane i-pentane c-pentane

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    StyroChem

    Blo!ing Agent Degree of Distrib,tion (has a direct affect on

    cell si#e)

    Expandability

    Heat sensiti"ity

    Str,ct,ral strength

    F-Gactor (ins,lation properties)

    Pereation rate

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    Blo!ing Agent.oo- Distri%ution of #lo$ing Agent

    Poor Distri%ution of #lo$ing Agent

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    Bead Si#e 0he larger the bead& the easier it is to achie"e

    lo! densities

    ess s,rface area for blo!ing agent to pereate

    o,t of

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    StyroChem

    Expander E,ipent Contin,o,s

    Batch

    8et

    Dry

    S C

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    Contin,o,s Expanders Description

    1aterial is fed into the botto of the expansion chaber

    !here it is s,b6ected to stea ,nder agitation& aterial

    expands and as density decreases& aterial rises to the topand o,t the exit ch,te5

    Fely on 0ie 2 0eperat,re

    S Ch

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    StyroChem

    Contin,o,s Expanders 1ain Controls

    Geed rate

    Stea press,re (teperat,re)

    Agitation rate

    ,tlet height

    Gresh air introd,ction (teperat,re)

    St Ch

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    Batch Expanders Description

    A pre-!eighed ,antity of aterial is dropped (or

    charged) into the expansion chaber !here either

    the expander !alls are 6ac7eted !ith stea (dry)2.or stea is in6ected into the chaber (!et)5 An

    agitator 7eeps aterial o"ing5 ac,,& p,rge or

    !ater in6ect ay be ,sed to stop the expansion5

    Fely on tie& teperat,re 2.or "ol,e

    St Ch

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    Batch Expanders 1ain Controls

    Stea press,re (teperat,re)

    ol,e or height

    0ie

    Charge !eight

    ac,, or p,rge tie

    8ater in6ect

    St Ch

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    Density Chec7 Consistency is the ey

    Proced,re

    Prep,ff is o"erfilled into a 7no!n "ol,e (pre-

    tared) container5 0he container is "ibrated or

    tapped ("ibration is ore consistent)5 A straight

    edge is ,sed to stri7e the top le"el !ith the canister5

    0he canister is re!eighed and the densitycalc,lated5

    St Ch

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    StyroChem

    Expansion - Behind the Scenes Beads Age& a575a5 1at,ring or Stabili#ing

    Internal oist,re 3fro condensed stea4

    pereates o,t of the bead

    Air pereates into the bead ,ntil internal and

    external press,res e,al

    Blo!ing agent(s) contin,e(s) to pereate o,t of

    the bead(n-pentane:i-pentane:c-pentane)

    St Ch

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    StyroChem

    8hy Age Prep,ffJ Goa becoes ore resilient after it/s

    stabili#ed Internal "ac,, a7es beads s,sceptible to deforation

    Fed,ces blo!ing agent le"els 0oo high a blo!ing agent le"el leads to excessi"e cool

    ties and heat sensiti"ity d,ring olding

    Dry prep,ff Ipro"es ease of transportation

    St Ch

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    olatile Content on Aging& .o%ati%es / 0123 R04235

    /2 074

    000

    100

    200

    300

    400

    500

    600

    700

    000 224 44 712 36 1200 1424 164 112 2136 000

    Time from Expansion

    &'(.o%um

    Volatiles Poly Volatiles

    St roChem

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    Aging ey

    A consistent en"ironent is iportant to pro"ide

    prep,ff to old !ith a consistent "olatile content

    StyroChem

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    Aging 0ie Controls En"ironent

    Air flo! 0ie

    0eperat,re 0ie

    Density 0ie

    Bead Si#e 0ie

    Blo!ing Agent 0ype(boiling point 2

    olec,lar coplexity) 0ie

    Polyer 1! 0ie

    StyroChem

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    StyroChem

    Expansion - 0ro,bleshooting High Density

    Ins,fficient stea press,re.teperat,re

    chec7 traps& "al"es& acc,,lator press,re

    stea flo! restrictedKoteL by onitoring both stea press,re and stea teperat,re& yo,/ll 7no! yo,r

    stea ,ality5

    Ins,fficient stea ties

    0oo high a thro,ghp,t thro,gh expander

    (contin,o,s) gi"es ra! aterial carry-o"er

    8et aterial

    StyroChem

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    StyroChem

    Expansion - 0ro,bleshooting High Density (contin,ed)

    Collapsed or o"er expanded prep,ff

    o! blo!ing agent content in ra! EPS

    Additi"e proble (bloc7 and shape EPS grades)

    Increased drop !eight

    Electric eye le"el too lo!

    StyroChem

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    StyroChem

    Expansion - 0ro,bleshooting o! Density

    High stea press,re.teperat,re

    onger stea ties

    Fed,ced drop.charge !eight 8et aterial

    "er dried aterial

    High blo!ing agent content

    S,rface additi"es (bloc7 2 shape grade EPS)

    Electric eye le"el too high

    StyroChem

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    StyroChem

    Expansion - 0ro,bleshooting

    Density Gl,ct,ations

    Inconsistent stea press,re.teperat,re

    Inconsistent stea tie

    Erratic drop.charge !eights

    Inconsistent eas,ring techni,es

    Inconsistent blo!ing agent content

    High static (affects electric eye)

    StyroChem

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    StyroChem

    Expansion - 0ro,bleshooting

    Density Gl,ct,ations (contin,ed)

    P,rge "al"e stic7ing

    ac,, probles

    Inconsistent !ater in6ect "ol,e

    Poor additi"e distrib,tion (bloc7 2 shape grade

    EPS)

    StyroChem

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    Expansion - 0ro,bleshooting 8et Prep,ff

    Coon on expander start ,p

    8et stea

    P,rge "al"e or "ac,, not !or7ing

    Poor air flo! thro,gh fl,id bed dryer

    0oo ,ch aterial in the fl,id bed dryer

    StyroChem

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    Expansion - 0ro,bleshooting

    Bead Collapse

    "er-expanded

    Excessi"e stea press,re.teperat,re

    Excessi"e stea tie

    0oo high an expansion rate

    0heral shoc7 after expansion

    Blades too close to !alls or botto of expansionchaber

    8rong additi"e pac7age (bloc7 and shape grade

    EPS)

    StyroChem

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    Expansion - 0ro,bleshooting ,ping

    0oo ,ch oist,re (condensate)

    Inade,ate stirring

    Excessi"e stea press,re.teperat,re

    Anti-l,ping agent le"el too lo!

    Hot spots in expander

    Excessi"e stea tie

    StyroChem

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    Irreg,lar Prep,ff (si#e.appearance)

    Poor or irreg,lar stea flo!

    Hot spots in expander

    Ins,fficient tie in expander

    Containation of prep,ff in ra! EPS (do,ble

    pass)

    Irreg,lar ra! EPS

    Expansion - 0ro,bleshooting