Document zQnD8OZQBMOEO4QY7d78DmMx0

BETH IB MUBHM.L liBBiM UBM# CLASSIFIED - RESTRICTED BABBS Jttl/ 5. A*** r_/ "'NDEXED" jL 29'53 NEPCRT HO 900 Pi3- 8 7?67 REFERENCE COPY NOT FOR CIRCULATION PARZ3V LABORATORY REPCRV au&reoi SBIXPPABJJ; PROTECTIVE SPRAT 0GATIHO8 XAYT RESEARCH 0OKTRAGT HOrdja* PERIODS JARGART lp 19** 10 JURE 30, 19*1 HOlEBOOEs vo ton &* ^ ' ^fvL-u WfiXOBD **8 0, o HSHPST 4 i a p p r o v e d b x k j p ftxniAnsx DUP030000955 CONTENTS X INTRODUCTION XX - RESULTS AND CONCLUSIONS XXX - DETAILED RESULTS AND CONCLUSIONS IV - EXPERIMENTAL T - CHARTS AND GRAPHS DUP030000956 P*RLXX UtBOJUTQRX REPORT SO. TOO SUBJKOTb ASRSPPASUB PROfECTXVS SP1U7 OOATIBOS SAPS' HESBAR0H OQBWAOT S0rA521* *| ~ IHROPPOTIOI Tho onbjootroooaroh aaA Aovolopaoat projoot waa aaAortokaa at tho rooaoot of Oho Baroa* of riaaaoo.. Bpoolal Projooto Sootlen9 aaAor Bavp Dopartasat Coatraot KGrA $220 la ardor to provldo * oprapablo otrlppablo ftl* for M la protbotlag ailltarar *nA naval oqaipaoat froa otrroolono fhooo filao woald bo appliods <l> For Initial ohlpaont ovorooas bp doaootio aamifaetnror* and Aopotio 0) For tomroPF otorapo anA far ottor ororwator aoroiioat la thoatros of oporatto* (o) For otorago of rooorvo stoOka aaA roplaooA oqaipaoat InaoAlatolpp aaA at tho eoaolmatoa of hMttUtto9 at varloao Aopoto aaA la tho SaltoA Statoo* Tho Initial control roqniroaonta not wp If tho Savf for a prodaot of this tppo woe lo TrovtAo'oorrooloa. protootlo* to oqalpaamt oovoroA with tho' fU*. Ixpoapro woalA laoiaAn baaidity rain* salt oprap aaA aoa vator* toaporataro woalA njf fro* troploal to aratlOo ThofiX* ohoala bo watorproof aaA olumlA aot paoo aero thaa two or. thrto froao of wator vapor por sqaaro rotor por 20 hoars a$ XOOfF^ oat 7$0 *: 2d Bo applloablo bp opropla* at root toaporataro bp aaobillo* porooanol to Bo oapablo of bolnp ooaplotoly strlppoA off tho port qaiatop bp haaA la tho Uold t BrlApo oponlnpa of oahotaatlsl Alarotor 5 Roolot fangua iaaoet aaA roAoat attaak 60 Haro ao dolotorieno offoot oa.aotal or wooA oarfaooo or oa paint ovor whlOh It nop bo applloAo Soot of thoso palnto oro alkpA or phoaollo bato DUP030000957 I ?o Reuala reasonably flexible and not eraek or oraxe on exposure to various types of atmosphereso to Provide a dry exterior surfaaeo 9 Bo oompatlble with the standard preservative lit uaedby tha dray and Bavy0 This report oarara tha results of six months work to develop aueh a product or products II HKgPIigfl AMP OOBOLPBIOBB Pro* tha varies* potential film former* lnvestl - fatad0 aprayafelto strlppatie pfoteotlv# composition* wort eveloped based oa ethyl cellulose <> nitrocellulose and neoprene The athyl cellulose composition has tha boat all round combination of phyaloal and working proportion and, os tha basis of data sow availableD la oonaldarad to ha tha aiost promising tha aitroaalluloaa sempositiea la eraally satisfactory is soat raapaota? but duo to ita inflammability it is oonaldarad inferior to tha athyl sails losao tha neoprene composition ha* certain dafinite *A vantages over hath tha athyl aad altrosdlulos* type* hat haoanaa it must ha vulcanised to attala ita optima* film properties and msat also ha a two paokaga proposition? It also la oonaldarad soooad to the athyl oollaloao type0 Detailed data oa tha composition aad properties -of tha above throe products aah ha found la tha hody of tha roporto One of tha aajor problems oaoouatarad in thia work was to dowelop compositions hawing good initial strlppahUily and good rotention of atrippahility on agings Surface active agents as a ola* wore found to prodnoo thia affaot with oao partlaular agent? soya lecithin? telng out standing in ita roduotion of adhesion combined with no do leterioaa affaot on oorroalon resistance. Sarly in the work with ethyl oeUuloao? one of the problems to ovaroono was that of obtaining aatlafaotery outdoor durability a It was found that tha durability oould ho definitely improved to a point haliowed to ho aatlafaotory by the use of a combination of an anti-oxidant aad proper pigmentation Still further improvement earn ha jbtaiaod by applying a topcoat of a black or dark gray flexible lacquer DU font 29 023 Black Daeo* was used in our experimental work,. DUP030000958 I m DUTAILED RESULTS AMD gOMtPfllOHS * surrey *a* uado of the available film forming Materials and ths nest llksly candidates wore selected for lureetigatlon flinoe a quite satisf&otory hot Alp atrippabXe protective coating based on ethyl eellulose bad baaa developed bp various concerns for the imy Ordnanoe Depart ant against specification AXkll$7, and because Saval Ordnance had found la their preliminary work ea this problem that tha aaat prmining feraulatioaa developed at that tlaa eontaiaed ethyl oalluloaa, this fora farmer was considered tha aaat pronlalng aaadldata for Initial werlu Othar filn formers sonsldered worthy of lavoatlgatiea wspa nooprsno butyl rubber2 Buna 80 #Vietaaex* 0 ,Thiokolt0 tha "vinylites^ "BtttMlts^ ^Ssm*, butyl isobutyl aethaerylatec methyl f .vXats9 nitrocelluloseD ealluloee aeetate and nylono Of tha abort 11s tad materials^ atrlppabla sprayable formulations wart developed using ethyl cellulose ultra eellulose, neoprenea butyl rubbers Buna 8<> parbunan poly vlaylbutyral and tha 50/50 interpolyuer of nbutyl isobutjrl metheorylate* ire van haa pat baaa don* aa tha othar candldatsa because ef their lass promising aharaotgristles or availability: and la tha ease of tha "Vfaplttea'b to arold dupXleatloa af tha work Aready being dona at tha Baval Ordnance Laboratory at Silrar Bpr&agp harylando Of tha etrippable, sprayablt foraraXatloas developed three shew tha aaat promise of meeting the doalfad require neats for a product of thla typto These vara baaed reapeet ively ea ethyl cellulose altraoeXlulosiaD and neoprene o Tha remaining formulations based aa butyl rubber0 Buna 8,, perbunan^ polyvinylbutyral end tha butyl Isobutyl pethaerylate lnterpelyasr were found to be lass promising and no further word ea then la planned at the present time* Because of tha otherwise prodsing rasuita abtaiaad with nitrocellulose*, a high spat evaluation ef eelluloat aeate -butyrate is underway to develop a leas Inflammable ooating 8a partiaaat results are as yet available > ,, <";> m > t <l . > > i > . v > The composition haring the beat combination of propertlaa for tha subject purpose is based aa ethyl celluloseo fhe present preferred formula oarrlea the du Pont experimental ooda J20a=X-dh63 and has the following compositions DUP030000959 J~200x6h6i Ethyl Cellulose (Etype) 35Op* Raw taster Oil letle #kk oil (StdoOll of MoJo Soya lecithin Phenyl<a-naphthylaaine Oarfcon Blaek Zinc Oxldt Hexane Toluene Ethyl Alcohol B-butyl alcohol Hl-*olv*noy laphtha (Union ^ Oil #30) OoiO 0,90 0,50 20,00 12,00 *,00 12,00 20,00 SollAa Oeapoeltlon ( OCMOMOPMMnMnMMVICMIlMnMIK,<P Xthyl Cellulose Raw Castor Oil Xstlc #kk Oil Soya lecithin Phanyl-a=aaphthy laaino Carhon Black Zinc Oxide kl>5* lc.,0 35>0 20 0>5 ko5 2o5. loo~5^' Solvent Ooapoaltlon ?3Z*M olveno Xthyl Aleohol K-fcutyl * Union Oil #30 250? 15o0 10o0 15-.0 loO Gallon Weight 60S9 pound* at 250, Viscosity (#10 Cup) 13S coo, at 25*0, Total Solid* * 20o0jB Tsnsile Strength * 750 - SOO lh*o/*q,. In, Elongation at Break * 55 \ 60s Beraaahllity train* WO grana/100 *qD n*ter*/hr0 at 39o50^ at a film Build of S nil* Theoretical Coverage * 263 aq, ft,/gal, at 1 nil FormulatIon <J'200-X 4>*M>3 1* reduced te 17 5^ total aolld* for apray application with J^3ooo-X-et*7o a thinner cenpeaed of the cane advent* In the eaa* ratio aa contained in J >200 X &tijo A film hulld of 7 9 nil* can he laid down in two cmaqr application* nhlng a prosauro pet apray gun 0 A BeTUhlaa MBO typo apray gun with aa FF typ and a #70* *hot spray* typo head la reeonaended whan applying J 200X-6463< A pressure of $0 pound* on the line and 20 pounds on the pot la raeocaendedo A fun of J'200-X 6^3 of S alia thlokaca* will dry to handle in 3 5 hours and la aoaplttely dry In 2k hours at room tenparaturOo It eaa then he readily atripped froaeteel and painted eurfaee*& ether than the pyroxylin typ*o DUP030000960 Baaed on preliminary expoaure data and accelerated weathering teata8 outdoor durability equivalent fa af least 3 to 4 momtha la Florida can bo expectedo The period of durable lift aan be materially extended*, however*? by applying a topcoat iwb aa 259-023 0 Black *Dneo*'E iwr tho otrlppablo soatlag without advcraely affooting Ita etrippability or ro alatanoo to earroeioa Vo oarroaloa oooura oa pollahod eteol toat plaooa 00atod with #^200Xio3 whoa toatod uador tho following eonditlones JJP Tea ooaaaoutlTo oyloa of8 16 houra at loo* relative tumidity at 100#Fo 3 houra at,"40*Ft> 2 houra at 3US00fo 3 houra lamoraioa la a 50 aalt aolutloa at JO*To 11though J-200~X>6463 offora good protection from oorroaion* ita moiature vapor permeability value la ooaaider > ably higher than that of aolatureproof *Cellophane 0 In our eealo (PTe * grama/100 aquare metera/hour at 39^5*0^ nnder a vapor proaaure differential oorroaponding to 100a relative tumidity oa one aide of the film and leaa than 3a on the other aide),? the latter haa a value, of 20 < 30* uheroae J 200-X 4443 haa a value of approximately 400 at a film build of V mllo (floe Chart 1) tho nitrooollulooe atripping laequer ia conal&ered to ho loaa interesting than the ethyl aalluloaa type mainly baoauae of its questionable Inflammabilitya shojpresent preferred formula oarrlie the experimental oode J-243-X 6447 and haa the following compositions DUP030000961 Hitrooellulose (6 3soends) io;oo* Phosphate SCO Oil (Std Oil of HoJo o 60 Soya lecithin Oo4o Carbon Bi&k 0o$0 Zinc Oxide 050 Hexane floOO Acetone 19.90 Ethyl Alcohol 3JU90 N-butyl s SoOO N butyl Acetate Solids Opaposi>fon Hitrooellulose 49, Trierssyl phosph*.tw39 2 EftlO #44 Oil 29 Soya lecithin 20 Carbon black 44 Zing Oxide 24 'AOd'CSS Solvent Composition Hexane Acetone Ethyl Alcohol Hbutyl * H-butyl Acetate 10>Q* 25,0 15>0 iOoO 0,0 Oallen Weight - 7te IbSo at 25&0> Viscosityv#10 farlin Cup ) * 192 second at 25d< Total Solid* m 20,4^ Tonsil* Strength * 2500 - 3000 Ibao/sq in Elongation at break 50 - m Permeability Value * 300 grams/100 sqo metera/hro at 39-5' a build of ail* Theoretical Coverage * 196 sq fto/gal at 1 ail at /emulation J 243 X 44f is reduced to 17 -5^ total solid* for spraying with J 3000 X 451r, a thinner composed of the saae solTents in the sane ratio as contained in J 24J -X 44jo A film build of f 9 ails can be laid down in two spray applications using the saae spray equipment and under the saae conditions as reeoanonded for the ethyl cellulose stripping laoquer It is also equivalent in drying epeed to the ethyl cellulose stripping laoquer and is readily atrippabla froa both bare ateel and painted surfaces other than the pyroxylin type,, Based on preliminary exposure data and considerable durability background with similar pyroxylin typo formulations J 24j -X 447 is expected to have satisfactory outdoor durability possibly being bettor in this respect than the ethyl cellulose typo, DUP030000962 Vo ecrrosloa oosurs to polished stool test pises* coated with J~243>X-644f vbw tooted under the condition* previously outlined in the 10 cycle teat Moreover, J >243 is somewhat more impermeable to noloture vapor than J >200^X6463y having a permeability value of approximately 360 at a film build of 6 nllso (See Chart X) Beeauoe of lta better combination of tenaile trength and dlateaalbllitjr at rooa topperatore than the ethyl cellulose stripping lacquer J >243 X 6447 ia more easily strlppableo Ibis would probably be advantageous Whan stripping froa Irregular shaped parts The mu % d s advantage of the nltreoelluloee type is of oourse its Inflammability,, This howevers would only present a problem after the eeating waa stripped from the parts and it could be minimised by exercising normal aare la seeing that large quantities ef the stripped film were not allowed to aoouau late, She third of th* most promising stripping lacquers is based on neoprenen the present preferred formula is oodod jn2oo=XH453 and has the following compositions XXV Veonrcno Phenyl^bnaphthylamino 12*g* Stearic mold f Oo2 Extra light oalolnod magnesia 0 52 Soft carbon black 22,01 Oirco ito process oil 1*26 Zinc oxide ' .1 . OoU Soya lecithin f #$ Pout #552 localerator Toluene Industrial xylene 0*30 jiOeLi5r* loo o6jt Solids Oomposltlon KSR Veoprene Phenyl b naphthy lamina Stearls sold Magnesia Sort carbon blask l&rao Lt.prooess u Zina otldo Soya lsolthln #552 Moderator 100, 0 290 20 4<>0 175 0 10,0 10 2 ,0 log Solvent Oomposltlon Toluene Industrial xylene "plpcridtnlun pentaaethylcne dlthlsoarbarmats 60 0* 40 0 tarty DUP030000963 (Sailor weight <<>50 IbSo at 2J0o Viscosity IfXO Farlin cup) m lb h ^o at 25^0O Total Solid. * 37^ ' .. **Tensile Strength <0 900 Xbso/sq^ X. Hodulua at XOOp elongation * 300 > 350 Ibs/sq. In ^Permeability valuo * 50 grams/100 aq0 meter/br, a at an < all fil* build ThoeretieaX Coverage * 431 sq ft/gal at X all film Tally vulcanised (2b hours at 150EFo) Unlike the two preceding stripping laoquera based respectively on ethyl and nitrocellulose which dry to their final file properties tar solvent evaporation^ the above composition^ depends for Its final film properties on vulcanisation* This par either be aeeenpllssd at an elevated temperature rash as In 24 hours at 1509FoP or upon aging at rooa toaporaturo for a period of one month to six weeks . %rlng tbe air dry tnieanlsation period the neoprene film provides Sood protection from oorroslon to tbe parts ooatod and is only efiolont In film strength which df course reduces the ease of stripping during this porlodc However0 it is possible to strip J 20O-X-6453 from the substrate after drying only W hours but not nearly as easily as when the film is fully vul oanissd formulation J 200 X 4^53 will not vulcanite as packagedo JUst before using, a vulcanisation accelerator and activator oust bo addo&n The immediate offoot of aaklng these additions is to cause a rapid thickening of the solution almost to the gel pointo Howeverp within \*o to throe hours the vlsoeslty returns to normal at which time the solution eon bo applied by spraying In the same manner ms outlined for the ethyl cellulose stripping lacquer Hero again a build of 7 to 9 mils e&n bo lapd down In two appli cations Xt should ba pointed out0 however B that the atablll^y of the motivated neoprene solution Is relatively shorty from fg to 100 hourSn{ See Ohart III) ThereforeP only the quantity of neoprene stripping lacquer that can be used up In this period should bo motivated at ono time formulation I 2G0^X #53 dries to a substantially task free condition in Id hours at room temperature and as . stated above will vulcanite to a toughs raalllent, readily strlppablo film in 2h hours at 1507o or in one month to six weeks at room temperature It the parts 00ated with J >200 X -453 are to bo placed in contact with oaoh other DUP030000964 9- within a wsek after toting coatedt they should toe dusted with tale after drying 24 hours In order to prerent sticking Preliminary exposure tests Indicate that satis factory outdoor durability can too expected from J-200> X >6453 as panels exposed one month In Florida and for 500 hours to ultra-violet radiation show no apprselatols weathering When subjected to the ten cycle corrosion test outlined previously, steel test pieces coated with J -SOO^X >6^53 tooth whan started in the test cyole before vulcanisation and when started fully vulcanised show no rust or corrosion The neoprene stripping lacquer has a low moisture vapor permeability value at a film build of & mile,.;. using definitely better In this rsspsot than either the ethyl or nitrocellulose lacquers and only slightly Inferior to aolsturoproof Bflsllophanea 0 On our seals. J 200 X 6453 has n permeability value of 50 grans as eonpsred to 20 30 grans for nolstursproof * Oollophans* 0 Although * 20OX has ths disadvantage of having to too vuloanlsod in order to obtain the optima film properties., and hones oust Jmra^the aseslerator and aetlvator packaged and added separately^ its tough resilient less permeable film is superior to the ethyl cellulose and nitrocellulose types In providing pretootlon from noehanloal damagescuffing and abrasion* In the development of the above described stripping lacquersp the following data on the various factors affooting ths physical and working properties of ctrlppablc protective coatings has been obtained As In the case of permanent protective finishes,, the working properties and protection afforded by a given film is a function of its thickness.. With strlppable films, in order to got case of strippablllty the film must have a total cohesive strength greater than ths adhesion of the film to ths substrate Ths minimum film thickness necessary will vary depending upon the tensile strength of the film in relation to its adhesion to ths substratum Tests have shown that a minimum build of 3 mils is necessary to get easy strlppability with ths ethyl oelluloee nitrocellulose and neoprene compo sifelons0 The effect of film build on resistance to corrosion has also been studied ard it has been found that corrosion increases as ths fS&m ckasss decreases , A minimum build o* 7 mils for the eihy. and nitrocellulose types Js necessary DUP030000965 to provide adequate protection fro* ecrreeieisp and that a slightly lover hull* of 5 Bile for the neoprene type will provide the tame protection These facts eerrelate to son* extent with the remits of the effeot of film build on . permeability^ HoweverP the property of corrosion rosistan*s involves fastore other than moist*** vapor ptftMabiliiij, Chart X shove that;1 within limits the moisture vapor per meabllity of a film varies almost inversely as Its film bail* It is therefore Indleated that in order to obtain naxinan ease of strippings minimum permeability and good oorroeion resistance a build of 7 9 nils .is essential Although the durability of a ftripplhg lacquer is affeetod by my factors it was found in the work done to improve the durability of the earlier ethyl cellulose etripp lag lacquers^ that major improvements can bs obtained by (i) proper pigmentation and (2) the use of anti oxidants such as phenyl * naphthylamlne end the monobeniyl ether ef hydro quinoneo Figc I shews the effeet of the use ef phenyl a naphthylamlnee while Figo XX ehewe the effect of pigmental!? on durabilityc In figo X both panels have bee* exposed one month in Florida The panel on the left le a oloar ethyl oolluloso stripping lacquer, consisting of ethyl oolluloso 40: blown castor oil 20, and Setie #44 Oil 40o Xt has failed by becoming very brittle and is unstrippable he panel on right le the sane ae the other except for the addition ef O phenyl a naphthylamlne Although it le not readily etrippable and has lest eons of its flexibility! it earn e . be stripped with difficulty I Fig XX all panels have been exposed one monvh in Florid* Looking fro* left to right the first panel is the clear described in the preceding paragraph the second is the cane pigmented with sine oxide the twd with red lead: and the one on the extreme right with carbon b&.a*4r. All have failed except the carbon black modification a*.though the sine oxide and red lead modifications are in better shape than the elear. In all oases it le only the lover throe quarters of each panel that was exposed An interesting effeot le noticeable in the red lead modification in fig XX . The red eolsr is oonpletely gene an the exposed portion becoming a dijrtjjf; grey.'. Fig' XXX Illustrates the offset ef applying a top seat over the elear composition . The panel on the right is the same as the one on tbs loft except that 2 coats off 259 023 Black "Dueo" was applied as a topcoat Xt Is still easily etrippable and exhibits good retention of flexibility DUP030000966 IX-- Pigmentation also hat & definite effect on ^ moisture vapor permeability of a xilm= Up to a eertaji poini an inoreaa* in pigment content doorcase* the permeablliy Value hut beyond this pointy it tends to rise again. This is particularly true in thinner lilme (See Chart II) One of the major problems oonneeted with the subject development was in obtaining easy strlppablllty and retention of strlppablllty on aging.. A search for a suitable stripping agent Inoluded examination of earnauba vaxn petrolatum a 'Searic aoid aluminum stearate^. a lead soap sold by the Union Oil Company of Oallfornia under the name Btoprust D , and a variety of surface active agents. Garnauba wax waa the only material tested which did not doorcase the adhesion of the stripping lacquer to the sab stratum., Stearic mold,, sine stearate, aluminum stearate and petrolatum improved the etrippabillty but only under certain conditions. Stopruat D. 1 and the eurfaee motive agent a as a class were found to promote easy strlppabllltyc but in most oases, they also tended to promote corrosion Ons surface active agent, soya lecithin,; la outstanding in its capacity to decrease adhesion and rather than promote corrosion it tends to improve the corrosion resistance of the lacquer to whioh it is added.. Stopruat B 1 also gave good strlppablllty with out promoting corrosion,. Soya lecithin is a o~lc^Aal materia, consisting of approximately phosphatide* and 35$ soya beau oil., It was found to be effective in ethyl cellulose nitre cellulose.? cellulose aceto butyrate, neoprene., polyvinyl- butyral and methacrylate type stripping lacquers < It is interesting to note that the Rustbans (standard preservative oils used by the Army and Havy) promote easy strlppablllty but have a definitely deleterious effeot on eorroslon resistance when used in nitrocellulose and ethyx cellulose competition*. These oil* are believed to contain odium petroleum eulphonat*Q a surface motive agent., which in Itself Imparts good etrippabillty;: but definitely poor oorreslon resistance to a stripping lacquer . Ill EXPERIMENTAL A, Bthrl Cellulose Stripping Laeoumr The work loading up to the development of the present preferred formula for the above compound is outlined below^ DUP030000967 12- (X) ShTl O*lluloa Ethyl cellulose is the most important ingredient in the for. ula because of Its outstanding retention of toughness and flexibility oror a wide range of temperatures Meet of the work has been dons, with the following grades of ethyl eellulose8 Hercules V14;, 142,, B-5 and S-100 grades^ ethoxy content * 46.2 to 4dn5J0 and with Dow s Standard 100 20 and 50 eentlpoise grades (ethoxy oon tent 4$ 5 to 45o5B)r, It has been determined that in order to obtain the maximum total solids at spraying risoosity eon elatont with good etrlppabllltyo toughness and flexibility and using the present plasticiser It is nsosssary for the film to contain a minimum of 4lo* ethyl eellulose with a Tlsooslty in the range of 30 > 35 eentlpolses Lower ethyl cellulose content. er elhyl cellulose having a lower risoosity yields films with lower tensile strength and elongation and impairs the strippabillty,. Higher ethoxy oontent as exempli > fled by Dow0 s Standard Sthoeel in comparison with the Hercules Btype tends to lower toughness also a but this difference is rather slight.. Chart 2? shows the offset of e thyl oellulose risoosity and ethoxy eontent on the tonsil# strength and die feasibility of a typioal ethyl eellulose stripping lacquer. <2> &&S&2&I2SS A wide variety of plasticisers were evaluated for use in this oompoun&o Among those investigated were8 a) Blown oastor oil b) law eaetor oil e) Processed soya oil d) Prooessod linseed ell e) Hovinol fj Vertex 10 gj Dibutyl phthalate h) HydrogemtttUfcmastor oil phthalate 4$ two rieinoleate plnetleisere (Baker s PB 16 , and PB 161) U) Triorssyl phosphate (k) dl (ptert butyl phenyl) non (5 tert butyl 2xsnyl) phosphate (l) Butyl phthalyl butyl glyeolate (mi o and p toluene ethyl sulphonamlde (a) Butyl stearate Of the above0 blown east# oil was unique in that it imparted satisfactory sirippabillty without the use of a DUP030000968 xy tripping agent 8trappable film can be formulated with the remaining plasticizers with the use of a surface active type tripping agent Raw sastor oil when need In conjunction with a stripping agent sueh as soya lecithin has the best combination of properties Judged from the standpoint of film properties;; outdoor durability corrosion reslstanoe and availability Blown castor oil yields a slightly better oon bination of teneile strength and distsnslblllty but It is slightly poorer in reslstanoe to ultra violet radiations and henee would not bo expected to have quite as good outdoor durabilityn (y) OllSn Rosins Wanes Etc (a) Sstlo jM&n a paraffin bass mineral oil supplied by Standard oil or Mow Jersey has been found to give the best all round properties;; yielding films with good stripp abilityp tonsils strengths distsnslblllty and provides good corrosion resistance, (b) Marathon Hyol #402,, a naphthenlo base mineral oii0 yields films with satisfactory strength and die tenslblllty and decs not impair the strippability However,, oorroeion,, testa indicate that it is inferior in this re apest to Sstlo #44 Olio (o) Armr and Hyy Rust Inhibiting Oils A number of rust inhibiting oils suoh as . Rustban 6oy and 6o60 St&norust 702,, W&540 and wa-466 have been evaluetedo Zn general,, eaoh of these oils im ported better etrippabllity than the Satie #44 Oil, with %athan 6o6 and VX466. Prservatlre Oil being outstandingly setter,, However,, Rustban 6o6ti which Is believed to contain a considerable percentage of sodium petroleum sulphonate, increases the moisture vapor permeability value and in oorroeion tests it is definitely inferlo: to Sstie #44 Oil, specially in the pressnoe of aoid accepting pigments such as sine oxide,, red lead and basis sine chromate She addition of sodium petroleum sulphonate to either Sstie #44 Oil or Marathon Hyol #402 produoas the sens deleterious offset oa permeability and oorrosion reslstanoe as does the use of Rustban 6o6 in the formula,, An Interesting sidelight oa the use of sodium petroleum sulphonate is its offset on the oorrosion re sistance provided by a film of either Sstlo #44 Oil or Marathon Hyol #402, When added to these oils in the peroentags believed to bo contained in Rustban 6o6. the oils so modified DUP030000969 when used directly over steel offer corrosion resistance equal to that of Rustban 606 and definitely superior to either of the unmodified oils However, when used in ethyl cellulose oeatings the effeot is Just the reverse (d) Petrolatum of Various grades has also been evaluated AlthoupTVe have obtained sons erratic results with petrolatum-; la general it has been found to Impart Improved strippablllty and oorrosien resistance to a film with a slight loss in tensile strength and dietenaibUlty, Amber Panao or fellow Parmo supplied by Standard Oil of New Jersey are the two most satisfactory grades from the standpoint of compatibility, but. do not appear to give enough added corrosion resistance or improved strippablllty to warrant their usto Amber Petrolatum supplied by L > Sonneborn A Sons,; Ins of Petrola Pennsylvania, imparts improved strippablllty but has poor oompatlbllity and does not improve the eorroslon resistance enough to warrant its use<> .(e) Lanolin was examined as a potential film modifier but doss noflppear to have any speoial merit,, neither detracting from nor Improving the characteristic* of the film-, (f) OumarMH was the only resin examined;It improved the oompaWHiity of tho other ingredients with each other, yielded good strippablllty-: toughness and flexibility, and tended to improve the impedance to moisture, vapero However-; In aotual corrosion tests it had poor ro slstanoe to corrosion with the film showing a high degree r? emulsification under high humidity conditions,, (g) Paraffin Wax was examined but only from & ademle standpoint as formulations oontalning paraffin wax mast bo hot sprayed and dried at an elevated temper- . ature However,- it materially lowered the permeability value and provided good protection from oorroelon. (h) Antioxidants A number of anti oxidants were evaluated for their anti corrosion and film preserving effects among which wore phonyl alpha aaphthylamino; Agerito Alba Agsrito Rasim and ligssjff Hipar Although none appeared to give any added proteot&Mt from corrosion and In some tests appeared to have a slightly deleterious effeot, phenyl a naphthylamine and Agerito Alba (commercial monobeaayl-ether of hydroquinone) DUP030000970 definitely inproire the durability of a% ethyl cellulose filfto with, the former being slightly "battor la this respe*. than tho latter Apparently their effeot la to slow down the degradation of the ethyl cellulose caused by the actinic rays or the sun in combination witheygoa fro* the $&&<. Phany: naphthylaaine was judged to have the aost benefioial effeot oa outdoor durability without haring aay deleterious effeot oa corrosion resistance figure Z illustrates the effeot of phenyl a riapb . laalne on outdoor durability0 As discussed la the early part of this report, tho panel oa the left la a olsar ethyl oellu lose flla while the oae oa the right is the sane eoapoaltloa plus Oo5> pbenyl^anaphthylaaine Both panels have been exposed oae aonth la Florida.-, the general effeet of plgmatlag this type of conpound is <lT a gradual rsdustion ia distensibillty and strlppabillty (2) no appreolable effeot oa tensile strength within the prastieal Unit of pignoatatloa (3) an improvement la the durability and corrosion resistance sad (A) a reduction ia the permeability value up to a certain point beyond which further plgwentaioa causes the flln to beooae acre permeable (Boo Ohart II). Among tho plgnents examined wore sine oxide., nag no slum oxidey red lead., basio sine chromate carbon black notalllo aluminum.. talc and ammonium forro phosphate Form iations hare been prepared with taeh of tho above plgnents which yielded flint with good strlppabillty , toughasss and flexibility Zinc ex?'de? aagneaiun oxide p red lead and basis sine ohronato have boon tasted clur their effect oa corrosion resistance and hare been found to be benefioial. Oarboa blaok apparently does not naterially affect tho oorrosion realataaoe but has been found to be the best single weans of Improving tho outdoor durabllltyo Zlae oxide and red load improve the durability somewhat but by themaelvea fail fairly rapidly (one aonth la Florida?o-Figarc ZZ l*ows the effeet cm durability of pignontlng tbs clear with sine oxide . red lead and earbon blaok The panels illustrated bars been exposed for one south in Florida.. Panel F--X Is the TfcdsiVgaeated lacquer In this exposure period it has boeone very brittle and ia unstrlppabls Panels 7 13 F lh and F 15 represent the olear plgnented with sine oxide.. red lead and earbon blaok respectively. Although the sine oxide and red lead nodifioatlons have rot failed as badly as the olsar,, it can be seen from the knife scratches that both arc quite brittle and do not have enough cohesive strength to he DUP030000971 u strippablCo The red lead formulation has also lost its original color with ths exposed part of the panel 'soing a dirty gray She carbon blaok Modification (F -155 ^ str .lx readily strlppable and has retained nest of its original flexiblli^r, Bencer from the standpoint of durab*,l1 y and corrosion resistans* ths present preferred formula contain, carbon black for maximum durability and a email er amount of sine oxide as an aoid acceptor to Insure good corrosion re istanoe Xt should be pointed out that only the lower three quarters of saeh panel has been exposed This accounts for the difference. |n depth of shade between the top and bottom of each panel particularly In the case of the red lead forme latioa0 (6) Stripping Agents One of the major problems in this work has been the development of a means to reduce the adhesion of the stripping lacquer and the retention of this reduced adhesion on aging Among the agents tried for this purpose were eamuntba wax stearic add; aluminum stearate dno stearate petrolatum a lead soap manufactured by the Union Oil Company of Calif ernia under the trade name Stoprust -1,, sod a variety of surface-active agents representing different typosn With \-2,* exception of camauba wax. %he remaining compounds wore found to promote strippabillty when added to the lacquer in miner quantities Stearic acid aluminum stearate., sln& stearate and petrolatum wore found to lessen the adhesion of ths lacquer to the substrate only under certain conditions and in several cases erratic and seemingly contradictory results wire obtained? The surface active agents which arc listed below were found as a olass to have a definite effeot on reducing adhesion Aerosol Of an alkyl aryl sulphonate Nsomerpin 5t n&phthlans sulphonlo aoid Alox 350) complex methyl esters of high Alex 850) moleunlar -weight. alcoholsadds and laotones Yslkin TT3 oil solublo organic phosphatlda Ultranate Ho 2 - sodium petroleum aulphonate Several other surfaoe active agents were tested and found to bo Incompatible DUP030000972 The first of these agents tasted was Ultr&a&te Bo 2 which is reported to be the anti oorrodeat ageat mss* fia the Ruethane o Bltranate Boo 2 dofinitely lowered the adhesion to equal, that obtained when Bn*than 606 was used m place of Katie #44 011r eaased an lnerease In the permeability value and had a definitely deleterious offset on corrosion resistanceo Xelkin ITS soya lecithin* was then tried and found not only to doorcase the adhesion equal to that offooted by Ultranate Vo 2. but at the sane tine tended to increase resistance to eorreelbno this van alee found to bo true of Stopruet Jl-lo Tests lndleate that the optimum asiount ef soya lecithin ia 2m ef the rohielo oolids The use of a tripping agent such as soya lecithin which will not only decrease adhesion but will pronoto corrosion resistance is valuable not only fro* this standpoint but it allows (l) n older choice of plasticiser, aa blown castor oil was the only plasticizer found that could bo used without a stripping agent. (2) higher pigmentation te get maximum durability and (3) leas lnerease in adhesion on aging m Solvents c~jr wmaeomo-wBamw The solvent mixture used is designed to have the optimum selvenoy to provide the minimum vlseosity at the maximum solids and to bo fast evaporating enough to allow a heavy build te be applied without sagging and without trapping air bubbles in the film* The fallowing mixture Is new needs hexane (25^) toluene ethyl aleohel (10^) butyl aleohel (15m) and a medium high boilings high selvenoy naphtha which corresponds to Salon Oil #30 (35m)n However under advoreo spraying conditioner, it may be necessary to nake eons adjustment in this mixture0 Senes a retardsr J-JOOO^mSp consisting ef 25 parts butyl aleohel aad 75 parte Salon Oil #30 is recommended to make this adjustment *ork to date to determine the optimum spraying conditions to obtain the maximum build in the minimum number of eoate indicates that (l) The optimum spraying viscosity la 70 te tfO secondsNm a #10 ?arlin eup at 25*00 Higher vlseosity causee bubbling while lower viscosity increases the number ef coats to obtain the desired film build (2) The air pressure at the gur should bo as high as praotleal: prefer ably above $0 pounds and as near to 100 pounds as possible Lever lino pressure causes bubbling by not producing a fine enough atomisation of the lacquer (3) The pot pressure DUP030000973 should be between 20 and 25 poundsa Higher pressure for09a more material through ths spray gun so that poorer mtemL.sai'., takes place< ill of the abort recommendations are based on the uae of DeVilblSf spray aqulpnent, using a type MBO epray,, gun fitted within S' tip and a 'hot spray* type head #y<A. Although 0tiier types of heads and. tips nay be used , the abort yield the maximum build in the minimum number of ooate without entrapment of air bubbles Other types of spray equipment ean undoubtedly be used jou^ the conditions of application would probably have to be changed aoatwhat tinder the above recommended eonditlone for spray S.ng a dry f11a build of 4- ails can be IS&d down on a vertical panel by continuous spray application before sagging beginss and without trapping any air bubbles Another appll nation of 4 ails ean be made within one half hour after the first Although the present preferred formula far J 200 X646J, ethyl cellulose stripping lacquer, represents the best composition we have been able to develop based on the work covered and may represent the optima percentages of the a.. desirable components further work le neeesa&ry to determine the beet method of manufacture > Zn order to obtain the maximum durability from the present composition it is planned to study the various methods of dispersing the pigments, th e factor being known to have a definite effect on outdoor dvrs billty <- treoelluloae Stripping League-.- She work leading up to the development of the present preferred formula for the above compounds is out lined below (1) nitrocellulose Nitrocellulose with a viscosity of six seeostde was chosen tor this work in order to iembine maxims* nos* with the maximum solids at spraying viscosity, &...* viscosity also oorresponds vary closely to the visooslty of the ethyl cellulose blends namely 35 eentipoiees (2) ..?la*t'.oisers, The following plastiolxers were evaluated^ DUP030000974 49 Trl-.^resyl phjSphat# 1 nh.K)nA!iAli(i HyW, gaaated wflfcor oil pfcth&^av* &a* castor oil Blow* -aetosr oil Blown cottonseed oil Of the**, dltmtyl phthaiate( hydrogenated castor oil phthalate and trieresyl phosphate gate filns with the 4^aaa% adhesion and .had the heat eoapatibili'-'y vi'^h. numeral ol;v- Due to the ana 4nfaaabilii/iJ non 'VoAav.Jlity m:A the good combination of flexibility and toughness vha^ triorssyl phosphate Imparts to nltroeelliiloee ^oapoibt ,o j 1b ; this plaatief.se*- was selected 03 Oils and Rosins etco Based on $he work done on the ethyl cellulose development asd to obtain the optima flexibility at lew temperatures ombSJWM%lth lack of thermopiastlcity at high temperatures., isejreaia ms contained ia this comp eitioii'. Baaed on thsjbaekground gained la the develop > aeat of the ethyl cellulose composition Bstio #44 Iras OOS.eeted aa the oil in* nitrocellulose eoaposition isannotn however tolerate the amount of oil that the eJhyl cellulose type ear (Jp versus 376i) vfc) Asfca Oxidants Although anti -oxidants sush aa phenyl a aaphthy laalne and Agerite Alha were tried0 there were sons indications that they promoted <aerrosiott,- Therefore:; the nitrocellulose stripping laequer contains noaSo i5) P:l.g*e#t# Based m the background developed &or pigmenting the ethyl cellalose stripping lacquer on corrosion and pro llalnary durability t^sts carbon blaok and sine oxide wer-i selected 4a.v C$3 stripping Agents Because of the good adhesion of the nitrocellulose stripping laeqtter regardless of the plasticiser used, a stripping agent is essential The following ooapouado wore tested for their offeot on strippablilty^ / DUP030000975 20 Ca> Petrelatw* -,b} 0*eag&<j Afi;.d ) Sine stearate ,d] Aluninun stearate a) Garnavba Wax If) Ultranate #2 (gi Soya leoithiu Hone of the above gave the desired degree of strippabllity except Ultranate #2 and soya lecithin Th. fmey, aa in the ethyl cellulose composition; had a deleter tone effdot on oorroaion reaiatanoe While the la&er tended to pronete oorroaion resistance Teats indicate that 2% aoya lecithin on the solid vehicle is ep;&!araR:. {y) Solvents Again, aa in the ethyl cellulose compose iio the aane general principlea were need to fonmlate tho solvent composition* Based on laboratory tests the present preferred composition is hexane <10>) sumtone (25>) y ethyl alcohol (l^K) n butyl alcohol (10). asd n butyl uaetate For advorso spraying conditions a retarder <J JOOC X W-52 eopposed of BO parts n tarty! aostato and 20 parts n bu.tyl alcohol is re.ommended for tho reducer, (B) Application The aane conditions of application are reeonmeadta, for the nitrocellulose lacquer as for ths ethyl cellulose aansly a DcTllbiss type KBC gup #704 head; FT Up vith an air pressure of 96 pounds on the line and a pot pressorof 20 25 pounds , The optinun spraying viscosity s s 0 80 seconds 'in a Parian #10 msp When applied under these conditions a dry filu build of T 9 nils can be laid down in two application apply isg tho second one half hour sartor tho first , further work on tho nitrocellulose stripping lacquer for the present will be confined to establishing the best nethod ef Manufacture to insure the naxlnuu outdoor durability.- 0 Booprone Stripping Lacquer 1* j. mm miTpnm <r ^ OwTrufTirmrw--nCi^iTr A modification of a neoprene paint developed by the Rubber Chemicals Division of the du Pont Oonpaay was used as DUP030000976 the baeie foraulatlon is the fallowing work dona '** de-*el<> ft strippable sprayable coating This product had prodded good protection from ecrros.ji.os is a previous evaluation isads by this laboratory and had exhibited poor adii.osJ.oa t<> stse?: {!>} Neoprene The neoprene used is this composition is the KlfR. grade* OK Neoprene, while being hcraical .*-siilar to tbs vther types and like them has good resistant to oils ** gasolines In the yuleenlsed state... is better adapted is thi s purpose i&r the following reasons- it gives lower solution vtstfoelt^ea. per fitting higher solids at spraying wl.soosj.ti.es {2 } ay the use of suitable accelerators and activates-* :.t an lew mil^aniaed faster than the other types at lower iesperataree.. and without applied pressure C2) FtasiaentatioB As m the *ase of natural rubber, the best re informing agents for XHR Neoprene are the arboa blacks <. Of those ordinarily used h&nnel black seal reinforcing black and soft blafc (Thcraax}. the latter gives the aaxiwua water resistance consistent with good tensile strength, resiliency and abrasion resistant.* Laboratory testa indicate that 175 parts of Sharas* per 100 parts of neoprene is opt* won Saallsr amounts of ^fcerwax: increase the *a*& m the Ills during the vttiUMulsat on period and tend to lower the water resistance : 'Larger Moan?* decrease the diet*'" . ,:ty a < Ensile strength. Ct) Xodmtre Marion* <gilfter are included .in the formula for specific purposes- 1^ Ca) *her: % auft 5ia,; Oxide . MagaeEU {extra light calcined} is a very important neoprene fi&epousyling ingredient ^hen need in eenju&etl'.oa with sinf oxide., it performs a 'Mwf8l4 fw.ct`<m {1} Xfc has the effect of increasing aodulus of elasticity and teneile strength of the vaXuanieed fils*' DUP030000977  >22 ' (2) It retards scorching during nixing and processing O) neutralizes any snail quantities of hydrogen chloride that nay be evolved during the vuloani zatlon period or when the filns are exposed to sunlight or other severely oxidizing conditions Zino oxide when used in conjunction with nagnesia laproves the physical properties of the vulcanized neoprene Alone it le not praotioal since it causes eooreh ing and prenature vulcanization, Based on the neoprene 1# zino oxide and nagnesia are considered to be optimum W terns. M Heozone S (phenyl betanaphthylaalne) is used as A stabilizer of the unvuleanized compounds and as an antl~oxidant in the vuloanized film-, Co) Oil, She oil used.; Oiroo Light Prooeaa Oil/ which is a high solvency petroleum derived oil.., aots as a softener for the neoprene It Improves the flexibility at lower temperatures but tends to decrease the resistance to gas diffusion (d) St eario Acid Stearlo acid has a threefold offeot on the neoprene stripping lacquer- (1) It acts as an aid in processing# preventing the neoprene stock from sticking to the rolls., (2) It reduces the tine for the sprayed film to oone to the tack free stage due to its blooning to the surfaceo (3) It decreases the adhesion# making a more easily strippable film Ho deleterious effeet on film properties or stability has been found Tests indicate that 2# stearlo acid based on the neoprene is optimum DUP030000978 Soy* lecithin is used 19. the neoprene compositilofe m promote stripping Teats indicate vhat Z% soya lecithin oa the neoprene is the optima amoun:; So deleterious effsfe<fc oa film properties- solution stability or vulcaniat.on "a obtained from its ust* (4) Vulcanisation As discussed in a previous section of this report, unlike the ethyl eSllulose sad nltroeelluloee types of stripp lag lasquer? which dry by evaporation of the solvents: the neoprene stripping lasqusr anst he vulcanised hr the addition of a vulcanisation aooolorator and aetlva^oTo The sprayed parte are allowed te dry lo to 24 hours la order that all the solvents are elialaated and then can he vuloaalsed in 24 hours at 150*F or la about one nonth to ala weeks at roost twperstiroo She fllas do net reach their optima physical properties end strlppablllty until fully vulcanised;, hut enough vulcanisation takes plaoc in 42 hours at rooa temperature so that the films are atrappable with difficultyHowever^ during the air dry vulcanisation period good reoistaaoo to corrosion is provided^ The addition of vulcanisation accelerators and activators to the neoprene solution as paskagsd causes an lamsdiats thlsksaiag of the 0elution which approaches the gelation potato However after one half to aa hour the viieoslty begins te return to normal and at the end of 2 ... 3 hours ie back to a normal spraying range for neoprene (5^/5 eeso in a farlta HO cup) > Tbe solution renatae stable for only a relatively snort tine of 50 to 100 houroo CSee Chart III} r, However even before the solution reaches a viscosity above the spraying range0 a dropping ofin good sprayability is saeountersd with the solution showing strtaginoss on spraying.. This sondition begins to oecu;a . between 24 and 42 hours after the addition ef the activate^ and accelerator la order to obtain the fastest room temperature vuleanlsatlon consistent with the maximum solution stability., a carefol belanoe ef aooolorators has boon worked out > It has boon found that l >2jf Aooolorator 552 (plporidtalum fentanethylene dithlocarbarmato) and 4jl Aooolorator 233 a hutyraldohydo aonobutylamino oondonaatlon product} based DUP030000979 0% the &soprens give the optimum resultsn Larger amounts of Accelerator 552 which also sots as a chemical plastic ^ for tbs neoprsne ant as a solution stabiliser slow up the galvanisation rats and laoroaso tbs stability of the f.vatot neeprea solution while nailer amounts hare tbs re erse offoot Smaller amounts of Aooolorater 233 ole* np \he mii .anlacatilon rate and benoe favor solution stability while larger amounts do not appear to bare any appreo.ii.able effect An either direction sine parts of a 50$ litharge slurry 3n xylene art used with oa4i part of AooeXerator 253 to Improve the motion of tbs latter flinoe a mixture of one part Accelerator B33 and nine parts litharge slurry loses its pottnoy in approximately ona month it will bo necessary to pmokago taob separately this should not present an ?nsurmountabls problem however as tbs sxaot amounts of Accelerator 233 and litharge slurry noodsd to aotiyato any given unit quantity of neopreve solution could bs packaged* It should bs pointed out that tbs. rssuits discussed above vers obtained from work dons on one lot of neoprene.. Although tbs conclusion* drawn are tbs reqplta of a number of oarefully run toots and are believed to bo reliable, tbs present unavoidable variation between batches of neoprene require that several lots of aeoprtns be evaluated along the same linos before positive conclusions can bs drawn, (5) SolT.aU Using the same general principles as were used in tbs sthyl sad nitrocellulose type stripping laequtrs to formulate the solvent composition; tbsjars sent preferred combination is as follows? toluene (60p) industrial xylene MM The recommended conditions for spraying the ethyl cellulose and nitrocellulose compositions are also applicable to tbs neoprene When applied tinder these conditions 7 9 mils man be laid down in two application with a half hour wait between application* For adverse spraying conditions Industrial xylo. is recommended as a retarder,. Bo further work is planned on the neoprene stripping X&oqusr until the results of the field test on J 200 X >6453 point the wayo DUP030000980 25 Do Butyl Rubber fwT caifc nww>wi w. A high spot evaluation of butyl rubber as a trlppablo proteotlTo coating vaa made beoauso of its h.gh degree of impermeability to gaaes lta exoellent resistant to eraeking at low temperatures and lta exoellent aging propertitan bating the broadeat plateau in lta ouring evr\|re of any of the other aynthetie rubbers. The exauinatlon of butyl rubber for the purpose indicated that It was inferior to neoprene In the following roepeoteg (1) Zt yield*lower eolide at praying viscosity (12,05) aa compared to 37 55 for neoprene.. making it naeeaaary to apply aiere eeata to get the aauae film build (2) It oebweba on spraying: waking it note dlffloult to applyo With a alow enough solvent mixture..; howeverr the fila will coalesce to a oontinuoua film- (3) urlng the drying period it tenda to trap bubble* in the film* duo to ita exoellent impermeability o To oteroowe thla it would bo woeoaoary to apply vesy thin ooate ao that aoro than two application* are naeeaaary to get the minimal til* build. (k) Zt Will not vuleanisu auffioiontly at room teape rature to yield films with enough cohesive strength to bo stripped^ Whan vulcanised for 3 hour* at SfiO'-T.. ,, the film* are atrlppablo with difficulty being still quite tender. Zt doea. kenreyer provide good eorroaion resistance to 00ated part* oven :'in unvuicaniasd state., S0 PerbnranC*C ,.\fc -aUMRMKJR. Z* A high spot evaluation of porbunaa indicatea that it does not have much promise aa a strippable protective ooatlng Forbunan has the f ollowing desirable oharacterist.,1 a (1) films of porbunan arrive at the completely s**t free state aa aeon aa the solvents are evaporated and (2; when allowed to air dry. its adhesion to oteel la very poo;, tripping very easily from the substratum in aa little aa 6 2 hours after application.. It however has the following properties which makes it loss desirable than neoprene aa a strippable protective coating DUP030000981 2$ , ^ .. (1) Xt yields lobar solids at spraying viscosity (18 0*j as ooapared to 37c$n for neoprene,, asking &t neoeeaaj? to apply more eats to got the saao build <2} St cobwebs on spraying Making It uora diffieulv to apply "iih. a alow enough solvent mixture however bill coalesce to a continuous filn <3) It vill not vulcanise sufficiently at roou teupsrature to develop desirable filn properties, bith t-.k, unvnleanlssd filn providing poor protection froa oorrosio^ to the parts on bhioh it Is eoatado (4) It is definitely Inferior to neoprene in aoistnro vapor pemoabillty after air dry vulcanisation (See Short I) Fv Buna S This oopolyaer does not appear to hare any advantages Obtr neoprene an a strippable protective oeating, and has the following disadvantages(1) It yields lover total solids {3A%) at spray viscosity than neoprene <37o5jl)o (2) Oobvoba on (praying bat coalesces to a eon iinaons filn if alow eaaggh solvents are ueedo (3) Mr toy vulcanlsates have poor adhesion to steel but hare beak fllaa bith very little teneile strength Oo Poly-iayl Butyral in evaluation of polyvinyl butyral an a filn forao;. in otrippahXe protective oeatings for the subjeot purpose indioates that it has sene outstanding properties but that its disadvantages sake it loss daairable than the ethyl cola loae^ nitrocellulose and neoprene types, Zte one outstanding ad^Tantages ia the tough, distensible fila it proriAes, When plasticised to have a tensile strength ef approxlnately $000 pounds/sq inch it has a distensibility of 130jf at the breaks Utrceelluiose oonposltlonn bith a tensile strength of $000 pounds/ sq in*h have only an elongation ef 4o% at the break,, fhs preferred fornula for polyvinylbutyral has a tensile strength of 3170 pounds/sq,. lnoh and an elongation at break of 3$0,,0p, DUP030000982 27 Polyvinyl bniy^ai compositions be made <> givs good protection iron corrosion and to have at,,>:"n*tcL i tripping ^Vi'S.vV -V The aals d sadvantagas at polyvlnylbutyra*'. ans in it* applisatioiio Total solIda in ths range of 10 is peasant art maximum Ana to tha oobwebbing asaountared on praylngo This alloira only vary thin films to ba applied at one flaw,.. This situation la aggravate* because oi tbs loir solvents necessary to keep csbvsbbing am paying to a minimum ever. at such lav total solids > H H-Batfrl Taoism nethaersrlate A sprsyable initially strippable lacquer was formulated with tha abive antsrpolymevn Bowever Ilka polyvinylbutyraX its main disadvantage is :Va application Sea to its poor spraying properties. whieh are characterised by oobwebbing only a very thin film ean ba la d d -m, in ona applioatio t On aging 2 weeks at 150Po tha film gains anough j l A adhesion to ba non atrippabla oven though it contains soya lecithin as tha strapping aganto This is thought to bs duo to ths thsmoplastioity of this composition at 150G0 Although nothing is known at ths peseni tisa && tha prateation Irron corrosion it nay provids. .its nolaturs yapor permeability conforms vary alosaly to that of tho ethyl and nitrocellulose * dispositions (See Ohart 1} OOXEli y/5M DUP030000983 rv DU P030000984 |$oo o-5 .<( <.$ o.t 0.7 o-6 o*$> & 7/OOH/2$V3J3V00//$UV^t> DUP030000985 DUP030000986 DUP030000987 DUP030000988 MURE II J DUP030000989 DUP030000990