Chemical Fibers GUSTAVUS J. ESSELEN Gustaius
the United States in 1934 more tliaii 199,000,000 pounds of rayon ( 6 ) as compared n i t h a little over 61,000,000 pouiids of silk, or more than three times as much rayon as silk. Although there were in Europe 3everal plants for the manufacture of artificial silk prior t o 1900, the first plant in this country n a s erected in Marcus Hook, Pa., by the Viscose Company in 1910; the following year the plant produced viscose yarn a t the rate of about 1000 pounds per day, the total production for the year being a little over 362,000 pounds. This factory was only about one-third the size of what is today considered the very sniallest plant that will permit of economical production. The next development in this country v a s the ectab1i.hinent of a small plant in Boston in 1914, for the production of cellulose acetate fiber. This plant uqed cellulose triacetate as the base, rather than an acetate corresponding more nearly to the diacetate as is the present practice. This attempt was somewhat ahead of its time; and epeii though considerable quantities of acetate fibers were actually sold to the textile industry and the possibility of cross-dyeing with acetate yarns was introduced, the company was unable to survive the difficulties of the post-war period. The Viscose Company was for many years the oiily large producer of chemical fibers in the United State.. I n 1916 i t .tarted to build a new plant a t Roanoke, Va.; and in 1920
LOCATIOS OF RAYONPL.4NTS BY STATES V=viscose; A =cellulose acetate; C = cuprammonium
N THE latter part of the first decade of the present century, when chemical fibers first appeared on the market under the generic name of Artificial Silk, a group of silk manufacturers appointed a committee to look into this young fiber and report whether it offered any possibility of ultimate success ab a textile fiber competitive with silk. After due deliberation, the committee reported that the fiber was so harsh in feel and so easily weakened by water that there Tvas no chance of its ever finding extensive use in the textile industry. That is what happens when men lack technically guided imaginations! Yet in spite of thi. report, there Tvere consumed in
R 0 4 N O K E , \'.4.,
J. Esseleii, Inc.. Boston, 3Iass.
P L 4 U T OF THE VISCOSE COMPkNY
642
JUNE, 1935
IhDDUSTRI \ L 4\!3 E \ G I \ E E R I \ G
PLAUT O F THE h i E R l C k S
CHEJIISTIII
63 3
BEI~BERG C O R P O R A T I O S , ELIZABETHTOS, TEXS.
its Leviistowii, Pa., factory was begun. I t was not' until 1921, however, that other concerns entered the field. The first was the Tubize Artificial Silk Company in Hopewell, Ya., using the nitrocellulose process, followed by the Indust'rial Rayon Corporat'ion in Cleveland, Ohio, and the Du Poiit Rayon Company in Buffalo, S.Y., both using the process. At present t,here are twenty-five operating u this country controlled b y eighteen concern?.
Adoption of the Name "Rayon" As the use of these n e ~ vcliemical fibers gradually expanded, it became apparent to one of the far-sighted executires of a large retail store in Boston that, as far as the public was concerned, these fibers were under a distinct handicap because of their name. He felt that the term "artificial" signified to iiiany people an inferior substitute, and he emphasized that in these new chemical fiber,. we had, not a n inferior substitute, hut' new and unique fibers with valuable properties of their own. For thip reawn he urged the adoption of it new name and finally "rayon" was agreed upon. This has since been accorded aliiiost universal acceptance as a generic name. In recent years, lin\%-ever,there lias developed a tendency for tlie textile mills t o develop, froni the \-arioiis cheniical fibers, new and distinctive fabrics for special purposes and to give each type of fabric a iianie of its own. These fabrics are being accepted by the purchasing public bec.ause of their intrinsic attractive qualities; and feiv, if any, questions are asked as to whether they are rayon or silk or both. The appeal of the fabric to sight aiid touch are sufficient.
Present Producing Units .It tlie prezent time there i j a total installed capacity for rayon iiiaiiufacture in the I'nited States of about 225 iiiillioii pouiida annually and a coiisiderable i1icrea.e in t lie celluloFe acetate capacity i s under way. Of tlie present, operating capacity, about 78 per cent is represented by the Tisense proce-
about 3 per cent by the cupraninioniuni process. tion of the-e various plants is as follows:
The loca-
Viscose process Viscose Co. Viscose Co. Viscose Co. Viscose Co. D u P o n t Rayon Co. Old Hickory. Tenn. Richmond, T'a. Cleveland, Ohio Covington, Ya. Rome, Ua.
D u Pont Rayon Co. D u Pont Rayon Co. Industrial Kayon Corp. Industrial Rayon Corp. Tubize Chatillon Corp.
Elizabethton, Tenn. Asheville, X. C . Utica. N. Y. New Bedford, Mass. Kocky Hill, Conn.
North American Rayon Corp. American Enka Cor Skenandoa Rayon S e w Bedford Rayon Belamose Corp.
&%,
Koonsocket Rayon Co. Delaware Rayon Co. Hampton Co. .Imoskeag llanufacturing Co. .kcme Rayon Corp. Cellulose acetate process: Meadvilie, P a . Waynesboro, Va. Amcelle, Md. Kmgaport, Tenn. Rome, Ga.u
Tiacose Co. Uu Pont Kayon Co. Celanese Corp. Tennessee Eastman Corp. Tubize Chatillon Corp.
Cuprammonium prooess: Elizabethton. Tenn. Gloucester City, N. J.&
American Bemberg Corp. Furness Corp.
Sitrocellulose process: Hopewel!, a N o t operating
Tubize Chatillon Gorp
Rayon Production During 1934 the total rayon proclucd in the 1-nited dtatenap 210,331,000 pounds ( $ ) of wliich 163,000,000 were viscoqe
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and about 40,000,000 pound. acetate, the balance being chiefly cnprarninonium. Figure 1 -lion the aimual production of rayon in this country m i c e tlie e-tablisliinent of the industry in 1911. I n the fourtem year- -ince 1920, donieztw
rayon pr(JduCtl011 has multiplied fourteen times. This r e n i a r h able growth ha. been due, in large m e a s u r e , to the relentless research n h i c h h a s been applied to the iniprovement of thiindustry. The first “ a r t i f i c i a l silk” waq harsh to the feel and e a d y disintegrated b y w a t e r . It waq the boast of silk buyers that they could tell fabric5 made of these nen fibers n i t h t h e i r eyes closed. Thi. boast iq no longei heard. I t i. said t h a t in thi. period a single one of the loiiger operating companies spent about $10,000$00 on rehearch and development. Rayon manufacture, considered as a .cries of clieiiiical reactions, i) a n intricate and complicated operation It took a number of years before the industry T\as able t o bring all of the variou5 operating variablei under control. Iluriiiy this period it was not i~~icc~i~iiiion to have trouble with iiiieven dying from batch to batch; but intensive study of the variou. -teps, together with rigid control based on the re-ult- of t1ie.c studiey, has happily eliniiiiated this particular difficiilty Thi5 TI a- the firqt major contributioii of chemical re-earcli to the rayon industry. At the -ame time that uniformity \\ah being attained, the itrength of the fiber, and their resistance to water was a1.o being improved. In 1928 a modification of the visco.e proce.s wac announced XT hich claimed to give yarn.: nh1ch, even nlien wet, nere a i strong a \ natural silk, and n h e n dry were several times stronger However, thi. modification ha. not as yet achiered any wide coniniercial application. The yarns were harsh to the feel and tended more to break nlieii bent tlian iiornial rayon fibers. Thiq tendency interfered
lvith its use in weaving and knitting, and this fact, combined with the high acid costs involved in its manufacture, seems to have prevented its becoming a commercial success.
Delustering From the very beginning the chemical fibers have beeii characterized by a luster even higher than that of natural silk. For a few uses this was a n advantage, but for moht purposes this high luster was generally considered not so attractive as the more subdued luster of natural silk. Here again, chemical research developed methods of modifying the luster, and it is estimated that today approximately 70 per cent of all chemical fibers are made wit’h a more or less delustered effect. There are two general types of process for delustering, one producing a greater effect in this direction than the other. T o produce a fully delustered yarn, a pignient, usually titanium dioxide (S), is dispersed in the cellulosic solution from which the fibers are made. A surprising feature of this process is that the pigment is introduced liefore the cellulosic solution is filtered, the pigment being >() adjusted in amount and in particle size that it is not removed in the careful filtering steps which are an inherent part of all rayon proceses. i i n unexpected result of this introduction of pigment into chemical fibers was an unusually large increase in the wear on the mechanical equipment, particularly the metering pumps. This feature will he discnssed in detail later in the paper.
Coiirtesu, Z e n i t h Productr Company GE4R FIGCRE 3. HIGH-PRESSCRE
P U M P FOR ACET4TE PROCESS
When a less drastic deludering effect is desired, mineral or other oils are dispersed in very finely divided droplets in the -pinning qolution ( 2 ) . While the oil in this condition is not actually opaque, its different index of refraction produces an attractive semi-dull effect.
Strength I n considering the matter of the strength of chemical fibers, a word of caution must be emphasized. A number of complicating factorq prevent the making of any flat statement with regard to it. In general, however, there has been, over the 1a.t seven or eight year.:, a real improvement in the itrength of these fibers, particularly of those made b y the viqcobe procesq. This applies to the wet strength quite amuch as to the strength when the fibers are dry. The following figure. (for which the author is indebted to one of the large rayon manufacturers) show the strength of 1.50-denier viscose yarn: 192T Coiutes~Z , e n i t h Products C o m p a n y
FIGCRE2.
METERIXG GEm
P U M P FOR I-ISCOSE P R O C E S S
Dry Wet Dry Wet
tenacity, erams/denier tenacity, grams/denier elongation, Ye elongation, Yo
1.43
0.53 14.5 12.7
1930 1.59 0.79 23.5 26.2
1932 1.58 0.79
27. 30.
1931
1.65 0 75 24. 28,
fields of knit. goods and xoveii good*. F I Jthe ~ four yearprior to 1934 there v a s a gradual iiicreaie iri the liroportioii o f synthetic yarn ~x-hicli\\-as used for woT-eii goods a n d a gradual tlecrease in the proportion used For knit goodr. In 1934, however, this trend TTaZ: reversed, ant1 in that, year the proportion of rayon used in s-oveii good. as coiiiparetl x i t h knit g ~ d vsa s only two to o n e ; in 1 , the pru::mrtioii had been very iiearly three to one. Tliii may also 1i:ive hat1 ail influence on tlie changed denier trend noted in the foregoing. There are several treiids in the chenii>try (if the synthetic film industry Iyhich are noticealile at tlie nionient. ('nrefully detailed studies of the cheniidry of lioth the +core ai!d the acetate processes are yielding re.wlt; which are IJeiiig applied i n intliistry to improve the quality of tlie reFultiiig yarn. The significance of >mall aniounts of impurities in the raw riiaterials ih being recognized, antl the influence 01' thc iinpurities oil the iuiiforniity of the cheriiical trea tillelits !la> I)een worked out. 8 t u d k such as there alioiiitl logically lead to methods of reducing the time cycle of tlie \-iscose p r w e.., inasinuch as they may lie expected to show vays of securing, in a brief tinie interval, change; which are now dependent upoii time-corisun~ing"aging" iir "ripening" procer-er. From the mechanical -taiidpoint, improvements are a1.o tlJ lie expected, and bhere is already the Furness process wliich i* a n iiidicat,ion of some of the possibilities along thi. line. From the standpoint of the yarns theinselvei! \\.e may lock
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for iiiiproveiiients in tlie n.earinq properties a i d al:o i i i thc ye&tance t o water. Khile cellulose will 1iruIial)ly aln-ays be in the picture as one of tlie chief r m - materiala in the nianufacture ( i f -ynthetic fibers, it i- not at all unlikely that our rapitl!y increa.;ing knowledge of organic coiiipr~und~ of high iiiolecular weight will tli.clo-e highly polynierizetl *iil)>t:iiices n-liicli eaii lie inatle a t low cost and v h i c h can lie convxtetl inti, ryitlietic filier- with properties distinct1 niore tlesirable tlmi tll(Jh? of our preqeiit-(lay chemical filler . The tlevelopineiit of clieiriical fillers during the l a d twenty-five year- in this country ha- Ijeeii plienoiiienal. -It thr iiionieut tliiarc. swiiis to Ix! :i lull in the hitherto .teady expan-ion, but thwe x ~ iei i ~ i i yiiidieation. that, the continuecl application of cheniicxl research to this industry will result ill an early resumption of this iinusual rate of growth. proliably along quite now1 lines. Literature Cited ((1) Schwarz, E. JV. I- layer from this treatment also yielded water-white oil. The tarry layer separated in the acid washing of the third portion recluired that the treatnient outlined be repeated before it yielded a water-xhite distillate. RECEIVED August 29, 1934.
