CHLORINATED RUBBER THE HISTORY OF A NOTABLE ACHIEVEMENT

Onc of tlic most rciiinrkable sulstnnccs, espccinlly from IL clieiiiiciil engineering point of view, is clilorinntcd rubber, wliicli wlien properly mnde posscsscs cst,rn- ordinnry powcrs of rcsistnnce to ncids, alkalis, oxidizing ngcnts, nnd ninny other corrosivc nncl solvent ngents.

Tt is also pcciilinrly British in t l tn t its iliscorcry, cnrly devclopnicnt, nnd modification for nhpt ion to commcrcinl use linvc nll bccn the work of English chemists.

Chloriunteil rubber wns first prcpmccl in 1585 in tlic lnboratory by Glndstonc and Hil~bert in coiincsion with tlicir well knon.n rcscnrcli on the constitution of rubber. I-loivcvcr, t h y mndc no investigation of its propcrtics, which reiiinincd unknown until it wis again prcpnrctl by tlic 1:it.c S. J . l’enchcy, t,lic wcll-known rnbbcr clicmist,, in. 1915, wliosc nictliod of prepnrntioii in tlic first iiistnncc wis by the action of sulpliuryl cliloride on ru1)I)cr solution. %ntcr l’criclicy prc1)nrcd it Iiy the tlircct riction of clilorine nnd Iic soon rccognizcd tlic vnlu;iblc properties of the nintcrinl.

\\’lion first pl:iccd on the tiinrkct clilorinntcd rubber, though cstrcnicly inert, stiffcrctl from tlic disndmntngc tl int tlic solutioiis wcrc wry viscous imd the film Icft by tlicir cwporntion wis correspondingly thin niitl \rcnk. C‘onscqucntly, i t wns not till after tlic work of IT. C. I>ychc-‘J’cnguc sonic ycnrs liitcr, mlio invcntcil II iiictliod for producing low viscosity clilorinntcd rulibcr, thnt any rcnl coniincrcinl dcvclopiiicnt could lie iiiniic.

A s n result of tliis ndvnnce ii siiinll pI:int was stnrtcd in 1931 n t \\‘nltlinnistow by Ih t c l Products, Ltd., t o tlc\~clop tlic coiiiiiiercinl possibilitics, and i n 193.1 this comp:iny, of which Dyclic-’l’cnguc is tlic tccliiiical dircc- tor, trunsfcrrcd its nctivitics to ncw works n t Grccnfortl, Aliddlcscs.

J5sscntinlly Ilctcl is clilorinntcd rubbcr niridc i n t~

specinl iiinnncr, involving the prc-t,rcntnicnt of tlic rubber, tlic csiict dctnils of ni:iniifricturc, :is in iiiriny 0 t h importnnt clicniicril I)roccsscs, not being nwilnblc for publicntion. Tlic net rcsiilt, Iio\vcvcr, is n product of siicli n iioii-viscous clinriictcr t,liiit i f ncccssnry 1111 to 50% cnn lie dissolved in ti solvcnt, fortning a brusliablc soliitioiLl/lt should be c~iipli;isizctl t l tnt “ IIetcl ’‘ is iiot oiily tin cntircly British invcntion, but is rdso tlic origind rrtricty of clilorinntcd rubber to tic ~iiiitlc into ii coiiimwcinl proposition.

Tlic nintcriiil, 11s nlrciitly indiciitcd, is ~ipplicd wit,li 11 l J r i d 1 or s p y , like p i n t , and dries in abo~it, two Iioitrs or Icss, nicrcly by cviiporiition of tlic solvent, leaving n toogli, stroiigly atllicrcnt, non-poisonous iintl non- inflnmiiialilc liliii.

~\mongst~ tlic siirfriccs, non-poroiis or porous, to wliicli t l i e ~iiiitcriiil crin be iipplictl lire iron, steel, or tiny o t h r nictiil, including giilvrtiiizctl iron, wootl, stone, rirtificiiil stone, pltistcr, concrct,c, ~isbest,os, iisbcstos-cciiieiit pro- iliicts, piper, lciitltw, rind fiihics, ninny of which iirc cstrenialy tlillicult for piiint.

Il’lic list of products to wliicli “ Ilctcl ” is rilinost coniplctcly rcsistriiit iiiriltcs cstrriortlinury rcritling. \\‘it,li I I very l‘cw cscrptions it includes i i l l wirls, inorgiinic or orgiinic, coiicciit~rtrtctl or dilute, sucli its, for csaiiiple,

sulpliuric, hydrochloric, iii tric, i n i d acid, acetic, chroiiiic, and even hydrofluoric, ns wcll as carbon dioxide nnd ntniosplicric corrosion. In tliis conncsion r i spccinl vnricty for iron and steel and otlier iiictal surfaces only is “ D.1I.U.” (Dctcl BIctal Undercoat), which contains othcr ingrcdicnta so that tlie film lins n wry high proportion of fiilely dividcd nictnllic zinc which gives in adiMion true anodic resistance t o corro- sion. Siniilnrly Bctcl is rcsistnnt to cvcry known alkali in coiiccntrntcd or dilute solntion, such ns caustic s o h , caustic potash, nnimonia, and nniinoniuiii salts.

Amongst a large nuinbcr of otlicr corrosive and rcac- tivc substnnccs thnt hnvc no effect arc sca watcr (brine) oxygen, ozone, chlorine, bromine, iodine, potassium cyuntde, petrol, bcnzolc, nnd all tar fractions, alcohol, nnil nictliylntcd spirits. Thc filin also is not ntTcctcd by n dry lieat 111) to about ZOOo F. and a wet (wntcr s:rtnrnted) lient 111) t o 100’ l?. nncl is nn elcetrical insulator of liigli quulity.

INDUSTRIAL NOTES FROM ABROAD

FINLAND Of tltc totnl Finnish iiiiports for 1836 of clicniicnls

and allied products Great, 13ritnin supplied 9./,, vtiluc f350,OOO. lGnl:ind with her large forest rcservcs nncl licr ccllulosc, p i i l p , and p p c r industrics, draws upon othcr countries for npprecinble quailtitics of clilorinc, cniist,ic sodii, Glnu1)cr’s enlt, sotliuiii c;irbonatc, alumin- iuni siilplintc, r i d othcr industrial chcmicnls. Two nciv clilorinc plants I inw bccn cstnblislied as R result of t,lic cspnntling ccllulosc indust,ry.

DENMARK l h r i n g tlic pist ten iiiont.lis sltipmciits of cryolite

from C:recnlnntl to Dcntiinrk rc:iclicd II. totnl valuc of 4,302,000 kroncr, iigriinst 1,453,000 kroncr during the siinic pcriotl hist year. ‘J‘lic t,rcidc is being 1i;uidlcd by tlic Kryolit Jlinc tk I-lnndclssclsknb, n privntc coni- pnuy that has bccn given n nionopoly on t h opcriLtion of tlic Grccnlnnd cryolite niincs.

U.S.A. For tlic first nine niontlis of 1837 Anicricnii exports

of clicniicnls iintl rcltitctl products (coal tar, inilustrinl, tind iiicdicinril) showcil 11 slitirp rise ngiiinst tlic corrc- sponding pcriod hist yciir. Nsports in 1!)37 \vcrc vnliicil nt (i(i iiiillion tlollnrs, 11s conip i rd with 52.3 iiiillion ilollrirs i n 1836 iiiitl 31 * 1 inillion tlollrirs in 1935.

:\pirt front varions miir-riilibcr plrist,ics tlicrc nre two cfycctivc syntlictic rubhers on tlic U.S. iiiarltct., Neoprcnc a i d Tliickol, nntl a t lcrrst, one fiirtlicr product, will be iiviiila1)lc. lndustrinl clictiiisbs Iiivc bccn working on t h s c synthetic protlucts in nll piirts of t h c t country, for t,licre is r i witle nntl growing iiitirkct for ti Ilcsil)lc, wirtcrtiglit, itisiilritirig iiintcricil t,Ii;it will resist; corrosiori rind wit Iistiintl lieat,. ‘J‘lic production of Ncoprcnc iv now aboiit 35 toils 11 \vcek, tint1 iis 11. result of tcclinicril iinprovcments in tlic iiiaiiitfricturiiig process iluritig the lust tlircc ycrirs tlic price Iias bccn rcduccil froin .J;Od to 0.75 clols. p r 11). !l’lie oittput of l’hickol is sniiillw, tibout, 8 ‘tons 11 \~cek, but. its idoption for