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# OAR Box 

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## Document

Number: 

# 75 ) 11-1-7 6 Docket Number: 

# A-94-5 2

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### •-B W S?- ; 

### : T

# i Ho w Lo w i s "Lo w Styrene " Resin ?

:3 £ *&lv!i^$.iy*J ^^^^^^^^^^^^W^^^^S^^^Sy^^^^^f^t^fS

ow , tha t i s aloade dquestio ni f

ever ther e wa s one . A s th e composite s move s forwardint o th e nex t century , th e answer

t o thi s ouestio n i s goin g t c becom e 3 mor e an dmor e important . industry; !

Man y regulator s stil l d o no t fully understan dth e mfferen^fi^jffi& n a n u n;aturate di polyeste r resi n an dapain t

o r coating . T o man y o f

them , th e styren e i n aresi n i s n o differ

en t tha n th e lacque r

thinne r i na n automotiv e coating . Thi s means tha t ther e ma y continu e

j t o b e regulator s wh o tak e th e overl y simplisti c vie w tha t source s ca n simpl y choos e lo w J I styren e resi n system s a t an y time , an dfor

an y application . Thi s belie f

i n di e pas t

ha s le dt o som e stardingl y inappropriat e penni t conditions. :

•'28- i ~&\. Ther e hav e bee n report s o f facilitie s tha t

were require dt o us e 18 % styren e conten t systems , M f- I t turne dou t

t o b e arevelatio n t o everyon e involve dtha t thes e resin s simpl y di dno t exist . | f| t Ther e ar e stil l companie s wit hpermi t limitation s o n styren e conten t rha t ar e unrealistic, 1 an dunworkable . Man y o f thes e facilitie s hav e resorte dt o rh e us e o f iner t fillers t o "lower " th e styren e $ j conten t ofth e resi nunti l rhe y reac hrhe 30% , o r 33 % styren e conten t

"b y weight " require d i n thei r permit . Thi s i s a n approac htha t ha s bee nbolstere db y th e Sout hCoas t Ai r Qualit y Managemen t

Distria' s Rul e 1162 . Thi s regulatio ncontaine dlanguag e tha t require dth e us e o f resin s wit h35 % styren e conten t b y weigh t

"as applied" . Th e "a s applied " equate d inert fillers wit hth e polyeste r solid s conten t

o f th e resins . Som e woul dargu e tha t

i t i s probabl y les s importan t tha t asyste mb e a"lo w styrene " systemtha n i t

b e demonstrate dt o b e alo w styren e emittin g system . 

### B yStev e McNall y Composites

Fabricators

Association Composites Fabricationl)unt 1998P. 3

Th e questio n remains , i s thi s highl y e dsyste malo w styren e resi n system , e answe r is , no ! No t

i n an y meaning

sense . Th e emission s testin g whic hwa s forme db y th e CF A over th e pas t fe w r s ha s indicate dtha t

iner t fillers hav e tiima l impac t o n th e emission s froma ticula r resi n system . Th e testin g licate s tha t

takin g a45 % styren e ce man daddin g filler

unti l i t reache s Vo styren e conten t

b y weigh t

doe s no t duc e alo w styren e emittin g system ic hi s similar

t o a35 % styren e conten t t resin . On e o f th e uniqu e aspect s o f niposite s manufactur e i s th e way th e ustr y answer s simpl e questions . 

## Question : Ho w stron g i s acomposite? " Answer : Wha t d o yo u wan t

i t t o do? " Unlik e man y metals , composite s :erial s d o no t

necessaril y hav e ineerin g table s whic houtlin e th e sical propertie s o f

th e material , an ds o e are man y variable s t o b e considere d nyon e trie s t o figure ou t ho w stron g stuf f is . Th e reaso n tha t

thi s i s importan t

i n contex t o f thi s articl e i s tha t

strength , t g wit hcertai n othe r

importan t

physi

properties , ar e imparte da s afunctio n i e resi n chemistry . Base do n wha t

anyon e migh t

striv e t o eve'i n afinishedproduct , ther e i s a t variety o f

inpu t material s whic hca

n aried . Th e variou s anhydrides , acid s glycol s tha t

ar e use di n manufactur

th e bas e resin s eac himpar t specifi c iica l propertie s t o th e "backbone " o f resin . Thes e physica l propertie s affec t fina l engineerin g propertie s o f th e he dcomposit e product . Jus t a s afabricato r

ca n var y rh e typ e ber , fiber orientation , fiber

content , fiber length , i n orde r

t o affec t "ho w i g thi s composit e is" , th e resi n ufacture r can modif

y th e ratio s o f

ra w :rial s i n aresi n syste mt o achiev e dproperties . Al l o f thes e variation s impac t ho w ig , o r ho w resilien t

o f ho w resistan t

a cula r resi n wil l b e t o certai n chemical k . Thes e propertie s ar e vita l t o th e le dcomposit e produc t

bein g usefu

l icceptabl e i n it s intende dapplication . A n additiona l issu e regardin g th e resi n formulatio ni s th e ability o f th e manufacture r

t o proces s th e resi n in an efficien t fashion . Th e best-finishe d produc t engineerin g propertie s will no t mea n athin g if

th e produc t

canno t b e produce defficiently . Poo r processin g wil l ensur e tha t

th e produc t

wil l neve

r b e brough t t o market . Polyeste r resin s ar e comple x lon g chai n polyme r

chemicals . Locate dalon g 

### Styrene has been a Volatile Organic Compound

(VOC) for many years now, and

to the extent possible, regulators have put pressures

on facilities to lower their overall emissions

of VOCs.

th e molecul e ar e reactio nsite s wher e th e polyme r i s abl e t o crosslin k

wit hothe r molecules . Thi s i s wher e styren e come s in . Styren e readil y wit hth e crosslinkin g sites . Styren e form s bridge s amon g th e reactio n sites , an dthu s permit s th e material t o crosslin k readil y an da t

lo w temperatures . Goin g bac k

afew year s rhe compos ite s industr y ha dn o restriction s o nth e amoun t o f styren e the y coul dloa dint o th e resins , whic hwer e bein g used . A t tha t time , rh e resi n manufacturer s pai datten tio n to , primarily , rh e require dengineer

in g propertie s o f

th e finishe dproduct , an drh e proces s engineerin g demand s o f thei r customers . Ove r th e years , regulation s hav e begu n t o impos e aslightl y different poin t o f vie w o n th e industry . Styren e ha s bee n aVolatil e Organi c Compoun d(VOC ) for man y year s now , an dt o th e exten t possi

ble , regulator s hav e pu t

pressure s o n facil

itie s t o lowe r

thei r overal l emission s o f VOCs . ^ Thi s wa s don e t o lower th e amoun t o f "tropospheri c ozone " o r lo w leve l ozone . Hig hozon e level s are on e o f th e primar y component s o f "smog" . Th e EPA measure s overal l ai r qualiry b y evalu

atin g th e day s aregio n doe s no t excee d th e Nationa l Ambien t Ai r Qualit y Standar dfor

ozon e concentration . A s on e migh t

guess , th e Lo s Angele s basi n ha s lon g bee nth e hom e o f smog . Th e Nativ e American s inth e are aha d referre dt o i t

a s th e "Valley o f

Smoke" . Th e adven t

o f industrializatio n an dth e developmen t

o f th e Lo s Angele s Freeway syste m( asyste mo f

interlockin g roadway s precisel y designe dt o produc e gridloc k fo r extende dperiod s o f

tim e every day ) helpe dt o mak e th e naturall y poo r ai r qualit y i n th e are aeven worse . Th e Sout hCoas t

Ai r Qualit y Managemen t

Distric t

wa s give n th e almos t impossibl e tas k

o f improvin g th e ai r qualit y i nth e Lo s Angele s basi n t o th e level s mandate db y th e US-EPA . Overal l th e tas k befor e th e SCAQM D wa s t o reduc e VO C emission s fro mman y differ

en t classe s o f

sources . Thi s wa s th e motivatin g facto r

whic hle dt o th e devel

opmen t o f thei r Rul e 1162 . Rul e 116 2 wa s th e first

regulatio n t o hav e asignificant

impac t o n emission s fro mcomposite s facilities . Thi s regula

tio ntargete dstyren e conten t o f th e resi n a s aparamete r

whic hcoul db e quantified , monitored , an denforced . 116 2 becam e atemplat e fo r additiona l regulation s i nothe r area s o f California , an di ncertai n area s o f othe r states . 

### Force d to Chang e A s industr y becam e involve di n th e developmen t

o f th e MAC T Standar dfo r rh e composite s industry , th e industr y wa s force dt o chang e th e way i t viewe dstyren e an dstyren e emissions . Styren e i s no w a "hazardou s ai r

pollutant " (HAP) , accord

in g t o th e EPA . I t

ha s bee n aHA Pfo r som e time , bu t

onl y recentl y ha s thi s becom e importan t

fro maregulatory

perspective . A s Titl e V o f th e Clea nAi r Ac t ha s bee nimplemented , composite s facilitie s acros s th e countr y ar e viewin g styren e as a nindividua l pollutant . No t lon g ago , styren e wa s simpl y on e o f al l ofth e VOC s emitte dfro mafacility . I nsom e area s o f

th e country , afacilit

y coul demi t

u p t o 25 0 ton s pe r

yea r (tpy ) o f acombinatio n o f

VOC s before i t

wa s considere da"majo r

source" . Unde r

Titl eP. 4

V , ne w stat e emission s permit s hav e t o conside r rha t 1 0 ton s o f

an y individua l HAP , o r 2 5 ton s o f

an y combinatio n o f HAP s mak e afacilit

y amajo r source . Thi s get s aroun dt o aticklis hare ao f th e definitio n o f

a"lo w styrene " resi n system . Wha t

abou t othe r component s o f aresi n system ? Ther e are anumbe r

o f resin s whic h hav e combine dmonomer s t o sho w a lower "styrene " content . I s thi s a"lo w styrene " system ? Possibly ! Bu t

realisticall y th e indus

tr y need s t o loo k

a t thi s questio n very carefully . 

## Idea l Monome

r Ther e ar e certai n aspect s o f styren e whic h make i t a n idea l monome r

fo r th e indus

try . I t i s highl y reactive . I t

i s inexpensive . It i s marvelou s at

dissolvin g th e binder s i n fiberglass reinforcements . I t ha s afairly lo w toxicity . I t

work s extremel y wel l i n roo mtemperatur e an dlo w temperatur e curin g systems . Ther e ar e som e variant s o f styren e .vhic hhav e fairl y goo dpropertie s i n polyester resi n applications . Alph a Tiethyl styrene , par amethy l styrene , an d dny l toluen e are thre e tw o o f these . Thes e monomers , i n som e respects , nimi c styrene . The y hav e adea r regula

- :or y benefit , i n dia t

the y are no t

regulate d Tty th e EPA as HAPs . Currently ! Anothe r monome r

whic hsubstitute s b r styren e i s methy l methacrylate . Thi s rhemical i s aHAP , an daVOC , an di t ha s ;om e additiona l problem s whic hnee dt o ) e considered , whic hwil l b e addresse d hortly . On e proble mwit hEP

A classifica

- :ion s i s tha t

the y onl y reflec t

currentl y ivailabl e toxicit y an dcarcinogenicit y lata . On e o f

th e larges t

reason s tha t tyren e i s aHA Pan dalph aan dpar a nethy l styren e are no t

i s becaus e styren e s widel y use dan dha s bee n extensivel y tudied . I f

alph aan dpar amethy l styren e vere mor e broadl y used , the y woul db e inde r mor e scrutiny . Ther e is n o reaso n t o believ e tha t hes e styren e substitute s woul dno t >ecom e HAP s if

th e industr y were t o >egi n t o us e the min quantity . Additionally , thes e styren e substitute s lav e muc hgreate r

odo r problems . I n nan y case s odo r

complaint s are mor e of a egulatory proble mtha n anythin g else . Additionally , thes e monomer s ma y are 8 Composites Fiibrirntioiil}une 199 8 no t b e a s reactiv e a s styrene , whic haffects resi n curing. . Therefore , us e o f

alph aan dpar a methy l styren e o r

viny l toluen e offe

r limite dresolutio n an di s no t alon g ter m optio n fo r

achievin g "lo w styrene " resins . Methy l methacrylat e present s a differen t proble maltogether . Thi s monome r i s ofte npartiall y substitute dfor styren e i n ge l coats , an dsometime s i n resins . Methy l methacrylat e i s aHAP , an d aVOC . I t

i s mor e toxi c tha nstyren e i n man y respects . An di t

tend s t o emi t

a t a rat e significantl y highe r

tha nstyrene . 

## Methyl methacrylate presents a different problem altogether. This monomer

is often partially substituted

for styrene in gel coats, and

sometimes in resins.

Th e EP A sponsore dtestin g o n gel coa t emission s recently , i n partnershi p wit hth e NMMA . Th e result s o f thi s testin g gav e som e troublin g results . Styren e emission s fro mgel coatin g ar e approximatel y 50 % o f th e availabl e styrene . Emission s o f

methy l methacry

lat e i n thi s testin g wer e a t 75 % o f th e availabl e monomer ! Thi s i s increasingl y troublin g i ntha t man y companie s ar e no t

properl y consid

erin g th e methy l methacrylat e portio no f thei r resi n whe nmakin g report s t o th e EPA , o r whe ncalculatin g emissions . Fo r example , ther e i s a"lo w styrene " ge l coat o nth e marke t

tha t contain s onl y 16 % styrene . Thi s materia l als o contain s 22 % methy l methacrylate ! Simpl e arith

meti c woul dsho w thi s t o b e a38 % HA P conten t system , bu t

i t reall y emit s at

a highe r characteristi c rat e tha n a38 % styren e system . Th e EPA , currend y doesn' t wan t t o regar dth e differentia l i n emission s betwee n styren e an dmethy l methacrylate . Properl y addressin g thi s issu e woul d gread y confoun dth e developmen t o f th e MAC T standard . But , tha t doesn' t absolv e th e sourc e fro mproperl y regardin g thes e emission s withi nit s permit , o r

i n reportin g it s emission s i nth e TRI . Th e industr y i s currentl y sufferin g problem s associate d wit husin g inaccurat e emission s factor s (AP-42) . Improperl y regardin g emission s fro mmethy l methacrylat e wil l certainl y creat e thi s sam e proble mi nth e future . So ! Wha t i s a"lo w styren e resin" ? Well , i t i s agenera l purpos e resi n wit hles s tha n35 % styren e conten t "as supplied " (no t

"a s applied") . (Corrosio n resistan t resin s ofte n requir e muc hhighe r styren e contents. ) I t i s apigmente dge l coa t wit hles s tha n 30 % styren e conten t "as supplied" . (Clear gel coat s an dtoolin g gel coat s mus t contai nsubstantiall y highe r styren e contents. ) I t i s no t (i n ameaningfu l sense ) a resi n o r gel coa t

tha t ha s substitute d methy l methacrylat e for

styren e o n aon e for on e basis . I t may b e (fo r

th e tim e being ) a materia l whic hha s substitute dalph a methy l styren e o r

par amethy l styren e for styren e i norde r

t o get belo w 35 % styren e for aresi nan d30 % styren e conten t for a gel coat . An dth e challeng e stil l exist s fo r materia l supplier s t o d o abette r jo b towar dreducin g thes e number s eve n more , ft Steve McNally is Directror of Government Affairs for

the Composites Fabricators Association



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