Document xjOoEXe84mpoLOZarV3V8vNM6

LI A 0CQ 4 4 't ?fc:r '* .-i.f, 1,'i,*, -' _- t - o tCi.- -; ,.') Ar_ ismr iv, a. r. rsTAtuc l e a b rr-puvc;-* c j .> ja, u"o r~ - - - -----r-,% 3? r* r ' - * LrLr:;a C-J-lca (cuapcasold) ?. Br.r-tte-rTH E. Z. (fc. "-ant Ci Knawsr* and Co., to date i the cle nanufeetur-T ef Teflon. They procesj it to produce * '*.<*> suspension which Is aold in turn to Industrial oovotoaerw Ouch a* the amfactuiKra of corrolr handlif^ equip* MBt. 3. nrRoepcTToa This Bulletin has been prepared in order to acquaint *cber of the * Lead Indurtrlea Association with new tank llmjvr raterial rtieh ia rtlU in the drealopetent etape but which cay conceivably coepeto with leed lining* * providing the Manufacturer's clalna ere realised. Teflon i a plartio developed by dupont which ha* been in u# for several ye'r * a corro*!co reslatint Mat'Tlcl far use aa packt-p, gasket# and In aixilv adnor application*, but bec-u*# of in poor working ehiracteriatiee and corpleta lack of solubility, It had net found each use aa a t*r.k lining r'terial. K-vsrrr, r?a-".rrh< r.a at duMont recently cTLrcrjv> the preties of applie/'tlcB to tanas by grinding the finiahod plwtlc into particle* fine eno^h to fon a colloidal auspension and applying thif to tank walla by the apeeial aethoda described beIce, The clairj being wade in tho technical press about Teflon aoepenaoida ar* preamted in thia &-jlltln. They hare net aa yvt b*-n aobetsnllatcd by Hold oxptrionce and cnnecp.rotly a*y nenr live up to thn, Beeaues of aindlarltlrr in installation .jr-Uods, It la no*t likely that they will e<*p<~tO with gl*aa and perhaps rubber-lined ln*t*ll tlona. Ir.til a yrar fros now when duPont yeta into co.r^rclal prod a: linn it any bo difficult to predict with what Kitcrlals it will ooat effectively oorrp*tc on a coat bia ard to what caVnt it co--. titlon RAy bo felt, tut in ar.y nr nt .-*y-rs of the L ad Ind utrlca is*oelatlon will b aware ef tho exlrtn-.ee of Teflon wiap-.n*r>lds *.od eer.i'-vjrntly will bo In a bott-T poaltion to eofo with wtstnrer co-petition way acre lop. 0 ii ! N 3058 CKJ55CU. BCIL5TX* . 33 2 J!r73X, 1*50 it. m'"~JTir3 Tho proportIsa (lten below srs based on clalns mde by th Mnufaetmr* teflon (tstraflooroethylsne polyaer) l resistant to best ti" to about 500 F ard practically all chemicals with the extepilon of Bolton calelun, sodisn and pota-rlua and, r>der certain cordillera, flucrlno, It* high corrcalon rsc's'-srcs la fetched only by its hipn eoft and difficulty of fabrication Into ttscf-.il font*. The latter characteristic has bn acsBCfvt ev'rreovs by the devslopBert ct sprtyaMc Teflon aoipenscldn, cococsllfhed by grlr.dlnc the Teflon Into parade* etU eriov-n to fora a colloidal suspension In water, The autpesianid ccr.ts.lr.lry fron 35 to 65 per cent solids look# mssh like allk or creaa and ecn b* stored for sees lsn^th of tiae with littla or no separation. Teflon finishes will adi're to aany astala such as steal, alaaimm, brass, copper and to (lass (aft-r aaad blasting}, porcelain and brick, Abov* 75CP T Teflon aay break down and dcooapoee. BuPoat advertises the feet that *ithine sticks to Teflon.* This to a feed Indication that applying Tr.flro Unity;* to tanks will certainly require special tntU-nt to obtain proper adherence. 5. Brers or kjmj mt o i There aro three type* of Ttfloc opray eoetlvei prlsra, lut-'racdlat*, and flniah. Ib. process for spplylnc each la a Idler. Before sprsylnc the prlarr It is iwecssary to clean the vttl surface washing off grrast with a no1rent and preferably sand blastlni to as euro tho btrt possible atfv.-slon. After spraying, the ooatln? Is sir dried or faroo dried at teepr rU.r s tx. low J00 T to drlvo off tho carrying water. The vessel being eovcrvd Is th n heated cither by balrtn* In an ev n or by spot h- sting until the te*peraturc Is brought to around 750 F. It tMi point th- tiny part lei o of solid T.flon turn to a jell aid fuse together girtr*- s contlnoous film As the aital cools the fll-r boccra.! solid. If thin snots aro found or d'asgo occurs after use, th' finish can be patched. However to scccrrllsh this, t.V> area west be cleaned down to the octal, nore spray finish tpnllud and fss-d with blow torch or (as flsoe. 7hc total tbleiuv.ss of Teflon Mr.ldv'* rv-cessary to five protection against corrosion d-p.-nda upon tho nature of the chealeal to Wilch the finishes arc to be cxpoa.d, It is clsln-d that in (cnrrsl, s prln-r coat shost 0.3 nil thick, an lot -mediate coat and four to tlx finish coats of 1 all each arc Tv<i-jirod. For ulttnctc pmt ctirn against Best ch-olels, s gneUr \rgln of safety Is obtalnd by building up s b>*.vt r fUa. Far noro Inportant to store of Tcfln lined edulP'-nt Is Ur. fact that suitable tc-ta Bust U> applied to asjro fro*-don fron pin holes and eraek* before tho eq-ilpncnt can b put Into servlet. LI A f o c. 4 f. u m mm CBBOtsa WLLR7I . 33 -3- *mry 31, 1950 6, COSTS The cotta given below are buc4 on rtatcxents wade by the manufacturer* Zt would not bo unreasonable to assure th't 'hey rewrotertt the most fmroreblo cstinato* and that lining coot* for most cbaic&l vtaacls would bo far in euui of theto figures, particularly the ir cost* of preparation and installation. tteflon sprayed finishes currently core fro* |45 to #55 per gallon, dojvmding Ufwn the mslidt corVrt, One cnllor *1U cover about 300 square fbo# with a 1 nil coat. DuPont estimates that at preaent it would onat about *0 cents for materials and #1 for labor on a four-coat lining of ona square fool* Tbo coat of lining large vessels will BDdoubtodiy cacecud this fifuro. T. mnxBiuTf The product ia atill aery nr* and at 111 in tbo domlopaont atago. Zt will bo about another year baforo Teflon-llnod v-ceel a e*n possibly bo arail* able. IbPoct'a new Teflon auaprnaoid plant in Prrkrsturg, Vest Virginia won't bo ia production until crowd July, 1950. 0. COKCinSIOS Tbo newly developed apray ooatlng method of rppllection atorially adds to th utility of Teflon, the moat inert of all plastics, but tbo uScfiilo i i of water suspended colloidal Teflon is definitely handicapped by tbo followings first, tbo rurf*co of the vessel to be cower'd oust be suitably pro* pared before spraying. This usually Beans sand blasting since Teflon is noted for the fact that it sticks to nothing.* Second, the material is >xpcnslva and the labor and lire nccossvy to line a wessol adds still more to the oost of application. Third, eft r linin';, the vessel rust be v,t.,-d for freedom from pin boles rind creeks beforo use, fourth, s vessel oust bw beetl'd in nn oven or by spot heating to 750 f, In large vessels this can bo an expensive and embersooc rt-qulivnnl. About 7500 f Teflon nay break down and decompose, fifth, coating snUils four to six separate spraying end busting operations and evon then the actual ecatinp offers little protection against mechanical abuse* fas >d on tbo above hero arc somo points that may be useful in competing with Tofloes 1* Teflon linings ,-rv extrasaoly thinj they nay bo likened to paint fils and hence the inherent possibility of film failuro by erackln; and pin holes is always present* t, for the asm or perhaps leas cost a far greater thickness of lead can bo utilised thereby offorln; much greater protection to the metal beneath. j ! j j j WP ascot! WUSTW . 33 -k- **** Ji, 1950 J. forte* prercratlsa f-r rr..;-d Teflon lining* 1* both ousber* tost and arptneiir* re .ilrir.j sand blastir.j equljsant and expanslT* occur 1 ltd batUs'.j iet, An expariessed and *r<'c1*Hy trained lndirtd'j.ii EJt b* t:id to apply a Teflon lining, Soaida* th* poMibility of peer bending. hsattnf abort 750* ? may ease* tho Teflon to break down and deccapoa*. k, Accordinf to th* maaafacturer. all 7a flea lined t o * sels met b tiuro-ushly teatad tefer* being put into sorrtia. Pm hole*, eracka and thin spots wjr b* pretest and ar* difficult to detect* If uncorrnoted, their presence would 1**4 to early failure of th* Teasel resulting in *n expact1# lot*. S, Like Most plastic asterlals. Teflon aay crack or rupture ehao subjected to a eerer* or sharp blots, Ko eridenc* haa been offered to the contrary by the Manufacturer. 'Tlth linings of paint film thicknesses it eon't take snob to penetrate the Teflon. la short. Teflon (sespensoid) is Mr* sad therefor* is untried end unpruT** outside of the laboratory. f mmm LI A * C8DaaX, BOUSTW MO. 33 -L- *nuery 31, 17$0 3* Marfae* prep*rutloo for era-eyed fitflon lining* la both oafc*r#os4t and trpor.tlvs retiring aand blasting equipaent and expensive controlled h**-ir drvicea, An asparlersced and peelally trained In*4' rid,ial rust bo uatd to i -ly a Taflon lining. boalde* the possibility of poor bondlry, bon-wig abort 750 F wy oauea the Taflon to break dove and dsoorroaa. it. Aoeording to tho aanufasturer, ell Teflon lined veaael* wet bo thorourMy tested before t-.- p.-t into aenrlea, ?ln holes, eracka ar.d thin aprta tsy be prcitr.t and are difficult to drtoct. Zf uoeorrected, their prerenr-s eovtld lead to early failure of the veaeal resulting in an expansive loaa. i 5. Like oit plaetle eiUrlili, Teflon aty crack or rupture *h*n i subjected to a eevaro or aharp bio*, bo evidence baa been offered ! to the contrary by the aereifacturer. *iith linings of paint fila ( thlckncsace it aon't take *uch to penetrate the Teflon. In short, Teflno (euspeneold) la no* and therefor* la untrlod and onprevea out* Id* of the laboratory. 0