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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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
Secondary Expansion Controls ol,e of Expander
1olec,lar 8eight
Blo!ing Agent Bead Si#e
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StyroChem
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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StyroChem
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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StyroChem
Blo!ing Agent.oo- Distri%ution of #lo$ing Agent
Poor Distri%ution of #lo$ing Agent
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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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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StyroChem
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