The applications of cellulose acetate to the field of plastics

Abstract

Illie piist firc ycnrs Iiuvc sccn :I trenicntloiis iitl\~nncc-nicnt i n tlic npplicntion of ccllulosc ncetstc to the field of p l i i~t i~~, both in tlic inipro\wiiciit in pliysiciil eliririicteristics of tlic liiutcriiil iind in tlic grciitcr viiricty of forms in wliicli it can I)c producctl. A few ycrirs ago, wlicn cclliilosc acctritc bccninc cliciip cn011gl1 to iiiakc its cstensivc iisc on r i commcrciiil scnlc pmctic;ililc, it wis Iiut iiiituriil tlint one of its first iipplicntioiis slioiilrl he to ii protluct in wliicli pyrosyliii liiid bccn so cmiiicnt~ly successful, niiiiicly, in the production of i l tlicrrnopliistic iiiiitcriiil rcscnil~liiig cclluloid.Since 1869, when t.lic H y i t t lirotlicrs discovered tliiit ii tlit!riiio~iliistic ~niiteriril coiiltl IJC inride froiii nitrocelli~lose iilitl ciimplior, iiritl founded t lie orgiiniziition which later I)cciiiiic t.lic Cclluloitl C'orporiition, the prodiictioii of celluloid liris de\~clo~)ctl into ii trcinendoris iiitliistry. I n spite of tlic introduction of moulding iiiiitcrinl iiiutlc from synthetic resins, celluloitl h i s niiiint,iiinetl its importrincc in the Iditstic intlust.ry. Xow 110th of tlicsc iiiiitcririls arc bciiig rapidly rcpl:icctl by the cclliilosc iicctiitc plristic, tluc to tlic mnny iiiiiquc propcrties wliicli it po~scsscs. A~iiorig these 1iiiiy be cited its t Iieriiio~~liisticity, tlic cstrnorcliiinry riingc, delicacy, beiiuty, iiiitl stubility of the colours wliicli inriy bc produced, the ciise with wliicli innny of Sittiire's most oninincntiil materials, such 11s tortoise-slicll, oiiys, pciirl, qurirtz, i \ 7 0~, niiil)cr, I l l i I~~J~C , etc. pliisticiecrs. ITowcvcr, it may bc snid that no single plasticizer is suflicicnt in the mnnufacturc of cellulose iicctntc plnstics. It is ncccssnry to resort to a niisturc of plnsticiecrs, tlic ingredients of which dcpcnd on tlic method of processing, the nature of tlic ccllulosc iicctnte used, and tlic propertics which it is dcsirctl to impnrt to the product. Furtlicrmorc, siiicc cellulose ncctntc will stand n much Iiiglicr tciiipcrnturc tlinn pyrosyJin without any tlnngcr of csplosion, mnny new \vnys opcnetl up in tlic details of incorporating the plrist,icizcrs and processing tlic matcrial, to take ndwntnge of ivhicli n new tccliniquc was required. Most of the fundnnientnl ciiflicultics Iinvc now I)ccn ovcrcomc ; and tlic nest stngc in the dcvclopmcnt of cclliilosc :icctntc plestics lies in cstciitling the nppliciitions of tlic matcriiil. C'ELLUI.OSE th2ETATE PLASTIC ~h T E I t I A 1 , SA tlingrnniiiiiitic illustmtion of tlie methods of processiiig ccllulosc iicctntc is prcscntcd in tlic figure I)clo\v. ,, 1Iic first type of proccssing, stiirtiiig froin ti dope, criii bc ilidiciitctl in ii very few words. Tlic viscous solutiou ot ccllulosc ucctiitc iiud pliisticizcr, iiftcr bciug filterctl iind freed froin biibblc~, is clclivcrctl in the tlcsiretl tliickiicss u p " the highly-polished surfiicc of ii ivlicel, filiii is tlicii piisseil tliroiigli driers iiiid rolled up. 1 1 1 tlic produc...