p. 1



# OAR Box 1413 Prepped by Ollie Stewart



## Document

Number: 

# 77 ) 11-1-7 8 Docket Number: 

# A-94-5 2

Printed 7/9/2008 3:11:23 PM

Sheet 77 of 114P. 2 

# echnicall ySpeakin g y Bo b Lacovar

a 'irecto ro f Technica l Service s omposite s Fabricator

s Associatio n EP AAI R DOCKE T 

# ZD-X-7B
deducin g Emission s wit h Styren e Suppressants Ih e arsenal o f

styren e emission s reductio n technique s fo rope n moldin g include s lo w pren e resins , controlle d spray g techniques , non-spray appli ttion , an d th e us e o f film rmin g agents , whic h reduce i e evaporatio n o f

styren e onomer . Thes e film former s ar e calle d ipo rsuppressants o rstyrene suppres jits . Vapo rsuppressant

s ar e almos ta s ol d ; th e composite s industry , bu thav e ljoye d are-birt

h o f necessity , a

s amajor nission s sourc e reductio n metho d for i e ope n moldin g industry . Vapor-suppressant

s ar e aclass ofresi n iditive s typicall y base d o n aliphati c wa x impounds , suc h a

s paraffin, although roprietar y chemistrie s ar

e used i n hig h erformance formulations . Th e functio n f avapo rsuppressanti

s to rapidl

y phase :parat e fro m th e resin , an d for

m afilm o n i e surface o f

th e curin g laminate . Th e *ax y film inhibit s styrene evaporation , 'hich result

s i n reduce d styrene emissions . Paraffi n wa x was originall y used a

s a n lir-dry additive " o r rack-free additive " i assis ti n curin g a iminate , o rapost pplie d ge l coa t arface , s o i twoul d e sandable . ypically , sandin g a ured laminate wil l ;sul ti n "gumming p " th e sandpaper , whil e exposed t o di e oxyge n i n th e atmosphere . Th e airinhibi tion , however, onl y occur s i n a very thi n laye

ra tth e surfac

e o f alaminate . Th e laminate ma y b e ver y well cured , excep tfor th e boundar

y layer , whic h ha

s bee n expose d t o th e atmos phere . Thi s i s particularly tru e fo rorthophthalic , isophthali c an d viny l este rresins . DCP D resin s ten d t o air-dr

y o n th e surface and ar

e less pron e t o air inhibition . Th e use o f

paraffi n wa x a s a n "air-dry " additiv e cause s di e surfac

e to full y cure b y excludin g contactwit h th e atmosphere . Thi s result s i n asandabl e surface . I twa s discovered thata

n inciden ta l benefi to f

paraffi n wa x was thatth e film hindere d styren e evaporation , tiiroug h th e same mechanis m o f exclud in g contac twit h the atmosphere . Paraffi n wa x does hav

e adownsid e - di e wa x film ca

n reduc e the bon d betwee n laminates . Th e reductio n i n inter-pl y adhesio n can resul

tin serious structura

l failure i n cas e o f

delamination . However , mor e sophisticate d suppressan tformula owever , onc e th e surfac e gum " i s emove d th e iminat e sand s perfectl y well . Th e easo n forthi s i s tha

t nany polyeste r esin s ar e airinhib ted , meanin g they l o no tcure wel l
6 Composites 

### Interlamina r adhesio n

with parafin

with advanced

suppressant

formulation don s incorporat e adhesio n promoter s t o enhanc e bondin g o f

subsequen tplie s o f laminate . Additionally , dier e i s atimin g issu e whic h .effect

s laminate adhesion . Whe n usin g avaporsuppressantadditive , dier e i s a n idea l windo w o f

tim e forapply in g th e followin g laminate overacure d laminate . Thatwindo w may rang e fro m 2 hours to 2 4 hour

s dependin g o n th e specifi c additive , resin type , laminate ge l time , an d ambien ttemperatur e cur e conditions . Outsid e o f

di e window , th e laminate surfac

e shoul d b e completel y sande d t o insure a n adequat e bond . Becaus e adhesio n i s influence d b y a numbe ro f

factors , i ti s recommende d tha t yo u conduc tadhesio n testin g o n you r specifi c combinatio n o f material s an d conditions . Durin g the cours e ofth e CF A Styren e Emission s Tes

tProject , th e effect

s o f vapo r ("Technically Speaking" continued on p. 42)

*_:t_;_
. _/7?*__7-i_.: , r , ' " •'^-"

—• • • ' • .•. ' "_' a' ' " " , '.'_ V
_J Suppressant

with adhesion

promoter.

# •echnicall ySpeakin g (cont'd) P. 3

"Technically Speaking"

continued

fiom 36) ippressant s wer e examined , t o determin e i e exten t o f emission s reduction
. A s a suit , a n understandin g o f di e functio n o f ippressant s ha s bee n developed
.

. Fil mformatio n onl y occur s whe n th e surfac e i s i n quiescen t

state , tha t

is , whe n no t

bein g disturbe db y resi n transpor t o r b y manipulatin g th e surfac e wit h laminatin g tools
. Th e implicatio n i s tha t

th e suppressan t

i s onl y effectiv e durin g th e stati c (quies

cent ) curin g phas e o f

th e emission s profile
. (Fi g 1 ) 2
. Vapo r suppressant s produc e alarg e emission s reductio n fro mth e curin g phas e ofth e emission s cycle
. (Fig
. 1 ) 3
. Suppressant s vary i n effectivenes s wit h differen t combination s o f

suppressan t an dresi n formulation
. 4
. Suppressin g actio n varie s wit hresi n styren e content , wit hhig h styren eppm) 

## s o 

# iApplicationPhase \ RolK)u t \ Phas e Lugo Suppressant

Effect

" -_-»_____^ ^

Stati cCurin g Phas e Tim e

iStyre i Conten t % Weigh t 33 % 44 % 49 % t-Vapo r Suppresse dEmission s %ResinW t 4.6 % 7.5 % 9.3 % : ". Vapo r Suppresse dEmission s % Resi n W t 2.8 % 3.1 % 3.6% Emission s Reductio n -39 % -59% -61 %
fc -ft . J * ! 

## labl e 2 .{.f l Resi n Styren e Conten t % Weigh t 33 % 44 % 49 % .Atomized Spray Application (Chopping) Non-Vapo r Suppresse dEmission s % Resi n W t 8.2 % 11.5 % 14.0 % Vapo r Suppresse dEmission s % Resi n W t 5.2 % 8.0 % 9.2 % %

Emission s Reductio n -37 % -30 % -34 % resin s exhibitin g greate r overal l reduc

tion s dia n lo w styren e resins
. (Table s 1 &2 ) Th e difference s i n emission s reduc

tio n betwee n manua l applicatio n an d spra y applicatio n ar e aresul t o f th e emission s profile s o f

thes e tw o processes . (Table s 1 & 2)
. I n th e cas e o f spray appli

cation , alarg e portio n o f emission s i s los t durin g di e spra y transfe r process . Onc e th e resi n i s o n th e surfac e ofth e reinforce

ment , spra y applicatio n share s th e sam e profil e a s manua l application
. Becaus e th e vapo r suppressan t

i s no t effectiv e durin g th e sprayin g stage , emission s fo r thi s portio n o f

th e profil e ar e virtuall y th e sam e a s anon-suppresse dsystem
. However , onc e th e resi n i s les s disturbed , an dfinall y undisturbed , th e suppressan t begin s t o tak e effect
. Wit hmanua l appli

cation , styren e los s i s les s durin g th e trans
fe r stage , therefor e th e proportio n o f emission s reductio n o n th e back-en do f di e proces s i s greater
. Th e othe r

eviden t fac t i s tha t wit h manua l application , highe r styren e conten t resi n exhibit s agreate r propor tiona l reductio n i n emissions
. I t appear s tha t onc e th e suppressan t

filmi s forme d o n th e resi n surface , emission s ar e abou t th e sam e fo r

bot h hig han dlo w styren e resins
. Th e hig h styren e resi n emit s mor e styren e durin g th e transfe r stag e an d durin g roll-out , s o th e actua l amoun t o f emission s i s higher , bu t th e proportiona l decreas e i s als o greater
. Th e resul t i s tha t hig h styren e resin s rea

p agreate r

benefi t fromvapo r

suppressant s tha n lo w styren e resin s i n manua l application
. I n spray applicatio n th e difference s ar e blurre d acros s th e rang e o f

styren e contents , mos t likel y du e t o th e influenc e o f th e magni

tud e o f emission s durin g th e sprayin g phase
. Durin g recen t

testing , flow applica

tor s hav e produce demission s profile s tha t are similar

o r bette r tha n manua l applica

tion
. Th e combinatio n o f aflow choppe r ("Technically Speaking" continued on p. 35) Composites Fabricationl)une 199 8P. 4

Sectio n 112(d ) i s th e hear t o f Tid e III
. .d ) direct s EP

A t o establis hemissio n dard s fo r eac h category o r

subcategory jurce s liste dunde r

112(c)
. I t

allow s

. t o se t different standard s fo r

different s o f source s widii n acategory
. An dno w w e finally get t o MACT
. io n 112(d ) require s tha t

th e emissio n dard s (i.e. , NESHAPs ) establishe d e r thi s sectio n shal l requir e "th e imu mdegre e o f

reductio n i n •sion s o f th e [HAPs ] dia t

[EPA]..
. rmine s i s achievable..
. throug hth e icatio n o f

[contro l technology]... " ce , "Maximu mAchievabl e Contro l inology. " EP A i s allowe dt o tak e int o considera

costs , environmenta l impacts , an d g y us e whe n determinin g wha t i s evable
. However , 112(d ) tell s EPA th e standar dfor

ne w source s shal l no t •ss stringen t

tha n th e emissio n contro l sve di n practic e b y th e bes t controlle d la r source . An dth e standar dfor exist

- >ource s shal l no t

b e les s stringen t

tha n iverag e emissio n limitatio n achieve di n rice b y th e bes t

performin g 12 % o f in g source s (o r

for th e bes t performin g source s for

categorie s o r

subcategorie s

. fewer tha n 3 0 sources)
. Thes e imumstringenc y level s (o r "MAC T :s" ) are se t

withou t regar dt o cos t

o r r impacts
. Congres s assume dthat ,

. othe r facilitie s are usin g th e controls , the y are b y definitio n feasibl e an dachiev

able
. Thi s simpl e assumption , an dEPA' s derivatio n o f

di e floors for

composites , i s causin g u s n o en do f

trouble ; mor e abou t tha t nex t month
. Sectio n 112(e ) tell s EP A t o establis h thes e standard s accordin g t o aschedule
. EPA i s t o promulgat e al l standard s b y Novembe r

15 , 2000
. (There' s tha t pesk y Novembe r

1 5 again. ) Th e RP/ C NESHA P wa s originall y schedule dfor promulgatio n i n 1997 , bu t wa s recentl y move dt o Novembe r

15 , 200 0 t o allo w EP A mor e tim e t o collec t data
. Sectio n 112(f

) direct s EP A t o revisi t th e MAC T standard s an dissu e additiona l regulation s i f

th e MACT s ar e no t

suffi

cientl y protectin g th e publi c health
. 112(f ) i s know n a s th e "residual risk " provision
. Sectio n 112(g ) require s MAC T for new , reconstructed , an dmodifie dsources , eve n i f EPA ha s no t

ye t promulgate dth e appropriat e MAC T standard
. Yo u may recal l alo t

o f hea t an dnois e abou t

112(g ) afew year s ago . I n it s first propose drul e t o implemen t

112(g) , EP A classifie d styren e a s acarcinogen , an drequire dcase by-cas e MAC T an dpermi t revision s for man y o f th e day-to-da y operationa l change s commonl y mad e i n th e compos ite s industr y (like changin g t o ane w spra y gun)
. Th e composite s industr y wa s instru

menta l i n gettin g EPA t o limi t case-by

cas e MAC T requirement s t o constructio n

o f ne w source s an dreconstructio n o f exist

in g source s (wher e 50 % o r mor e o f

a sourc e i s replaced)
. An dEPA decide dno t t o classif y styren e o r

othe r HAP s a s par t

o f th e 112(g ) rule
. For industrie s wher e i t

i s no t possibl e t o enforc e an emissio n limitation , Sectio n 112(h ) allow s EP

A t o establis hMAC T as a design , equipment , wor k practice , o r operationa l standard
. Unde r di e RP/ C MACT , man y part s o f

th e indusn y will b e require dt o emplo y certai n equipmen t designs , materials , o r

work practices , rathe r tha n compl y wit h emissio n limitations
. Ther e ar e severa l othe r part s o f Sectio n 112(112(k) , fbr

example , require s EP A t o limi t

emission s fromnon-majo r source s t o reduc e cance r ris k i n urba n areas) , bu t

the y don' t

hav e muc h t o d o withMACT
. Nex t month : EPA' s developmen t o f MAC T for

composites
. O

chnically Speaking"

continued

from 42) vapor-suppresse dresi n ha s produce d .sion s i n th e rang e o f

1 -2 % o f

resi n ;ht , whic h i s extremel y low
. Th e flow ppe r ha s an advantag e ove r bucke t brus h han dlay-u p - th e flow choppe r ster
. Th e faste

r th e resi n i s transferre d he laminat e th e lower

th e emissions , itionally , cho p is generall y easier t o rat e an droll-ou t

tha n choppe dstran d

, s o bot h th e resi n applicatio n stag e th e roll-ou t

stag e ar e truncated , ltin g i n lower

emissions
. Shoul dyo u us e avapo r suppressant ? Th e answer

i s aqualifie dyes . I s secondary bondin g a

n issu e for you r products ? If

yo u are fabricatin g "on e shot " laminates , o r if structura l bondin g i s no t

a n issue , yo u are free t o us e almos t

an y typ e o f

suppressant
. However , i f

yo u are fabricatin g products , whic hus e multipl e laminate s an dhav e structura l requirements , yo u shoul d approac h suppressant s cautiously
. Yo u mus t selec t asuppressan t

tha t i s effectiv e wit hyou r

specifi c resi n system
. Additionally , yo u mus t

hav e procedure s i n place , whic hspecif y laminat e timin g and/o r sandin g schedules
. B y workin g closel y wit h you r resi n supplier , yo r

.a n tak e maximu madvan

tag e o f spec . t ii g avapo r

suppressan t tha t ha s th e require dadhesio n character

istics , an di s effectiv e i n reducin g emissions
. Whil e styren e suppressant s are no t suitabl e for

all applications , the y ca n offer

rea l emission s reductio n benefit s i n awid e rang e o n moldin g situations
. O 

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