e speak on development trends in the cellulose fiber
Windustry in Europe from our own viewpoint as head
of the Research and Development Division of one of the larger European viscose staple fiber manufacturers, Chemiefaser Lenzing Aktiengesellschaft, located in one of the smaller European countries, Austria. The position of our company is unique inasmuch as from Lenzing’s 65,000 metric tons of yearly viscose staple fiber production nearly 707&--i.e., 45,000 metric tons-are exported to all parts of the world each year. This comprises approximately 20% of the world export volume in viscose staple fiber. In addition to this, Chemiefaser Lenzing up until now has been completely on its own with no direct ties to a large and widely diversified industrial combine. So far, viscose staple fiber production is our only asset, and we have to keep u p on top, utilizing all opportunities of rationalization and automation to survive and be capable of opening the doors to other fields of business. I n addition to this, we will incorporate into our presentation of the development trends in the cellulose fiber industry the views of other large European cellulose fiber manufacturers. Their views are known to us, partly from close technical cooperation, partly from our participation in Unicel Inc. in which a number of European manufacturers cooperate. T o speak on development trends in the cellulose fiber industry anywhere in the world is nowadays not too easy a task. There are many colleagues in the man-made fiber industry who consider man-made cellulose fibers as something not worth spending the time and money. They feel that the development possibilities in the cellulose fiber field are limited and that producing cellulose fibers of any kind is offering too low a profit margin. We do not blame them. However, we feel they are
‘35 1940 Figure 7. 4
‘45
1950
‘55 1960 ‘65
Development of the world production of man-made fibers (I)
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
I I
EUROPEAN
Trendsin buropean Ceflulose Fiber Industry forgetting a lot of facts, some of which may be true for all of today’s synthetic fibers sooner than they might expect. Cellulose Fiber the First Man-Made Fiber
As a first answer to these pessimistic views concerning man-made cellulose fibers, we take you back a few decades to 1930. As you see from Figure 1, a t that time the total production of all types of man-made cellulose fibers, including cellulose acetate, amounted to not more than 200,000 metric tons. Other man-made fibers were not in existence a t that time. During the years until World War 11, the increase in world production of artificially made cellulosic fibers was indeed as spectacular as the development of the synthetic fibers. This development of cellulose fiber production was the more spectacular since the cellulose fibers had to pave the way for artificially made fibers in general. They had to carry the fight against the label of being a mere substitute product. I t did not help that during World War I, as well as during World War 11, they had to be used by European textile industry in disregard of their suitability in textile fields, as well as for other applications, in which they were unable to meet product requirements. The “substitute” label still sticks from that time. In our opinion, it is really necessary that man-made cellulose fiber manufacturers come together to fight for the acceptance of unbiased generic terms by trade administration authorities and to conduct jointly sophisticated marketing and advertising campaigns to overcome public reservations. We should at least learn from the synthetic fiber people who understood enough to glorify their new fiber developments with an aura of glamor. There are some signs in the European cellulose fiber industry that more people realize the necessity of such steps.
Future of man-made cellulose fibers in Europe depends on strong technology, bold new financing
HANS A. KRAESSIG
If we disregard the setbacks during the last war, and the Korean War, and during the recent recession, we notice the rapid production development continued a t a nearly constant and remarkable pace from 1945 u p until today. There seems to us no reason for being alarmed or even discouraged by the small decline in the period from 1965 to 1967. As shown by Table I (7) in 1968 also the cellulose fiber production gained a new momentum. I n addition, Table I shows that regenerated cellulose fibers are still by far the class of manmade fibers with the biggest volume, and they will hold this position for several years to come. However, it seems to us worthwhile to spend a few moments critically analyzing the situation created by
TABLE I.
the recent recession. T h e cellulose fiber and the synthetic fiber industries both were hit alike. T h e development of the world production of synthetic fibers was slowed to about half the expected progress. T h e blow was, in its consequences, much harder on the cellulose fiber industry. Some plants were shut down throughout the world, especially in Europe and in Japan. T h e reasons, however, were purely financial and economic. Due to the higher profitability of synthetic fiber manufacturing, some companies involved in both cellulosic and synthetic fibers had neglected their cellulose fiber production facilities with respect to building up rational unit capacities in regard to systematic replacement of obsolete equipment.
DEVELOPMENT OF WORLD PRODUCTION OF MAN-MADE FIBERS, 1966-68 (1000 M E T R I C TONS) Fiber type
Viscose (and other cellulose fibers) Celluloseacetate
1966
World production in 1967
1968
3000 360
3000 450
3105 510
Increase over 1967 +lo5
7 0 of Total man-made fibers
42.3
-
-
Total cellulosics
3360
3450
3615
-
-
Polyamide Polyester
1215
1315
1615
$300
21.7
Polyacrylonitrile Others
590 460 220 -
750 540 255
1085 725
+335 +185
15.1 9.9
2485
320 -
+65 +885
4.1 __
Total synthetics Total man-made fibers
5845
-
2860
6310
7360 3745
6.9
+60 +I65
1
+lo50
VOL. 6 2
NO. 3
49.2
50.8 100.0
MARCH 1970
5
Under the strain of the recession this forced them, or encouraged their decision, to shut down facilities too small for rational operation or technically outdated. This caused the world production capacity for cellulose fibers to drop by approximately loyo. Since the recession has been overcome, the world production of cellulose fibers has made a recovery. The remaining manufacturers have not only balanced the loss in production capacity, their output amounts today to a substantial increase in overall production. The conclusion from this analysis points to the fact that cellulose fiber manufacturing calls for increasingly larger unit capacities, for constant efforts to keep production facilities up-to-date, for introduction of advanced automation equipment, for getting more self-supporting with respect to raw materials such as pulp, caustic, sulfuric acid, carbon disulfide and others, and for neverceasing action in order to reduce production costs. Modern Technology and Financing Needed
Our company, as rnany other European cellulose fiber manufacturers are, is working hard to meet conditions. O u r large production capacity and our past and constant efforts to keep our plant modern and technically u p to date have saved Chemiefaser Lenzing during the last crisis, although the price fight was apt to hit us harder because of our high dependence on exports. Furthermore, the development of modern automation equipment, such as the complete automation of our viscose processing plant, and of specialized automated analytical tools for process control, has helped our efforts to reduce man power requirements, thus increasing productivity and helping the cost balance. Four years ago we built our own plant for sulfuric acid, and a few weeks ago we succeeded in buying the 250-ton-per-day pulp and paper plant adjacent to our mill. Last year we developed the so-called “Split-Weaving” (trade mark) process for polyolefin slit band fabrics using film rolls as beam on the weaving loom to replace jute fabrics for staple fiber packing. We will advance along this line. We feel that the time has arrived when the cellulose fiber industry can no longer afford to pay profits to suppliers of base materials. All the larger manufacturers of synthetic fibers have, for a long time, been their own suppliers of raw materials, such as hexamethylene diamine, adipic acid, caprolactame, terephthalic acid, ethylene glycole, or acrylonitrile. I n addition to this, all cellulose fiber manufacturers seek better stability through diversification into other products, such as synthetic fibers, nonwovens, artificial leather, and others, and through merger with partners strong in other fibers or in chemical products. Good examples of these tendencies in Europe are the “Xylee” of Vereinigte Glanzstoff, the diversification Courtaulds has achieved in recent years into nylon and acrylonitrile fibers, the development of “Split Weaving” of polyolefin ribbon fabrics by Chemiefaser Lenzing, and the recent mergers of Phrix with Badische Anilin & Sodafabrik, of Zellwolle Kelheim with Farbwerke Hoechst, and of Vereinigte Glanzstoff with AKU. 6
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Properties of Man-Made Cellulose Fibers
Speaking of development trends for industrially produced products, it is always a good starting point critically to analyze the benefits and the shortconiings in meeting application requirements. Cellulose fibers in general have quite a number of properties highly desirable in textile use. In Table I1 we have summarized all the properties relevant for an ideal textile fiber. We have evaluated the property characteristics of cellulose fibers with respect to the use requirement of textile goods. Man-made regenerated cellulose fibers have sufficient tensile strength for most applications. Their elongation a t break is high enough for textile use. Cellulose fibers show high thermal and good light stability, The excellent water vapor adsorption and desorption properties give cellulose fabrics a high wear comfort even under conditions of elevated temperature and humidity. Fabrics made from cellulose fibers are easy to dye. The chemical stability is sufficient for normal use and cleaning conditions. Discoloration is, under customary treatment, no problem a t all. Pilling or tendency to develop electrostatic charges is unknown with cellulose textiles. As with natural and synthetic fibers also, the cellulose fibers have, in fact, some shortcomings. Some of these disadvantages only became apparent with the introduction of the synthetic fibers into the textile market. High abrasion and crease resistance, fast drying and good crease recovery have gained ever-increasing importance with the growing demand for “easy care” textiles. Almost all the shortcomings of cellulose fibers and of textile goods made therefrom are related in one way or another with the hydrophilic nature of the cellulose molecule. Closely connected with the high degree of water adsorption are the low cross-dimensional strength, the low abrasion resistance, the low fatigue strength, the relatively low initial modulus, the low resistance toward creasing, the low crease recovery ability, and the somewhat flabby hand of cellulose fabrics. Water penetrating into the fibrillar interstices and being adsorbed on the surface of the fibrils competes with the interfibrillar hydrogen bonding. The rupture of these bonds allows molecular and fibrillar slippage and prevents the buildup of strains counteracting stress forces to help recovery after creasing. For the same reason man-made cellulosic fibers tend to defibrillate when abraded. The reduction of interfibrillar bonding upon wetting causes a marked loss in tenacity and a substantial lowering of the initial
AUTHOR Hans A. Kraessig is the Director of Research and Development, Chemiefaser Lenzing AG, A-4860 Lenzingl Oberoesterreich, Austria. T h i s paper was presented as part of the Symposium on Novel Processes and Technology of the European and Japanese Chemical Industries, 158th National A C S Meeting, N e w York, N . Y., September 7-12, 1969.
TABLE I I .
PROPERTY EVALUATION O F REGENERATED CELLULOSE FIBERS
Advantages
Disadvantages
Tenacities, sufficient for most applications
Loss of tenacity on wetting
Elongation properties, suited for most applications
Low cross-dimensional strength
High thermal stability
Low abrasion resistance, especially when creaseproof treated
Good light stability
Low fatigue strength
Excellent water vapor adsorption and desorption properties
Increase in elongation on wetting
Good washing and dry cleaning behavior
Relatively low initial modulus, especially when wet
Excellent dyeability
Low resistance toward creasing and low crease recovery, unless creaseproof treated
Reasonable chemical stability
High water swelling and low dimensional stability, unless resin treated or mechanically treated
Low discoloration tendency
No pilling No exceptional soiling tendency; easy to clean No tendency for electrostatic charge development
High water retention causing long drying times Low mildew and fungi resistance Relatively high specific weight Flammable, unless flameproof treated
TABLE 111. EFFECT OF TOPOCHEMICAL ACETYLATION O F COTTON W I T H REACTION M I X T U R E OF BENZENE-ACETIC ANHYDRIDE-PERCHLORIC ACID (30°C, 45 M I N ) AND O F EXTRACTION PEELING W I T H CHLOROFORM (10)
Sample
Tensile strength, g/den Cond. Wet
Breaking elongation, yo Cond. Wet
Wet modulus, p/den
Loop strength, lb/den
Cotton, scoured, 1.43 den
3.7
4.6
8.3
11.o
1.4
2.6
Cotton, treated with model mixture,“ 1.39 den
2.3
2.8
9.4
10.2
1.1
1.9
Cotton, topochemically acetylated, 1.43 den Cotton, topochemically acetylated and extractionpeeled, 1.32 den
2.2
1.8
6.7
10.9
0.9
1.6
1.6
1.o
4.9
12.0
0.8
1.5
Cotton, treated with model mixture,“ mercerized Cotton, topochemically acetylated, extraction-peeled and mercerized
2.7
3.1
8.6
9.8
1.2
1.9
1.2
0.8
10.2
12.5
0.8
1.4
a Model
mixture = benzene, acetic acid, perchloric acid.
modulus of cellulose fibers. The high water swelling causes cellulose fabrics to have low dimensional stability and the high water retention gives rise to prolonged drying times in textile processing and after laundering. I n this connection it is worthwhile to mention that nature has a unique solution to counteract the adverse effects of the hydrophilic nature of cellulose. I n the outer layer of natural cellulose fibers the fibrils are layed down in spirals of high pitch toward the fiber axis and in a highly interlinked crisscross fashion. This layer, the so-called ‘‘primary wall,” prevents lateral swelling and compresses the more or less well-oriented fibrils of the inner layers forcing them to assume a better aligned structure. This causes the increase in tenacity experienced with cotton upon wetting or mercerization. This we concluded from results of some recent experiments listed in Table 111. The removal of the primary wall was achieved by
topochemical acetylation and removal of the triacetylated outer fiber layers with tetrachloromethane. The removal of the primary wall was proved by electron microscopy. After the primary wall was taken away the tensile strength dropped on wetting, and mercerization no longer caused an increase in tenacity. I n the same study we found, however, that the protective effect of the primary wall toward abrasive forces seems to be small. Apparently the long spiral arrangement of the majority of the fibrils in the inner layers, namely the so-called “secondary wall,” is enough to act against defibrillation during abrasion. The efforts to overcome the shortcomings of cellulose fibers reach far back. Methods to reduce water uptake and water retention causing most of the defects have been found. They are mostly based on chemical crosslinking. However, cross-linkage cannot be considered as the final answer, since all the treatments with a wide VOL. 6 2
NO. 3
MARCH 1970
7
variety of different cross-linking agents cause a marked loss in tenacity and abrasion resistance which, in many cases, cannot be tolerated. The development efforts in the cellulose fiber field everywhere in the world were therefore directed during the past 25 years to develop spinning technologies resulting in new man-made cellulose-fiber types having higher intrinsic fiber strength, increased fiber stiffness, good dynamic relaxation properties, higher degree of lateral order and orientation, and a more highly interlinked structure. This seemed in the late forties still a very difficult task. All early attempts to produce artificial cellulose fibers with high tensile strength and high stiffness had resulted in products unsuited for textile use. The high-strength Lilienfeld fibers had failed since they were too brittle and had almost no abrasion resistance. From this and similar experience the belief had originated that contrary to the case in thermoplastic polymers, fiber making was limited with cellulose to a certain range and combination of low-strength and medium-elongation properties. This picture has changed completely since the early fifties. The finding of Cox and coworkers (2) of Du Pont showed that additions of so-called “modifiers” to viscose in combination with zinc ions in the spin bath retard dexanthation, hinder the formation of established regions of order, and enhance the possibilities of stretching. This made it possible to produce cellulose fibers with tenacities up to 8 lb/denier still having over 10% elongation a t break and loop strengths approaching 2 lb/denier. The advances made after this discovery are demonstrated by Figure 2 showing the improvements in conditioned tensile strength and in fatigue resistance of rayon tire yarn since the year 1940. This progress was the result of intensified research and development work. It has helped man-made cellulose fiber manufacturers to
i
2
‘* 1200 aJ Y
3 C
.-I .-C
0,
.-
L
300
m
C
. U
-
m
800-
.-C
200 $ x
5m
J aJ
m
-0
C
?
7
.-
m
C 0
5;
c.
2
3
400-
b, U
100
*
Figure 2. Improvement of strength and of fatigue resistance and reduction of secondary swelling of viscous tire yarn in the period 7940-62 (3) 8
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
maintain their position in the highly competitive tire yarn field, losing ground much more slowly than most experts expected. New Spinning Techniques
Initiated by this development of technically used regenerated cellulose fibers, new technologies for spinning textile types were being worked out everywhere in the world. As a direct brain child of modifier tire yarn spinning, the so-called “High Wet Modulus” processes were created in North America by the American Viscose Division of Food Machinery Corp. and in Europe by Chemiefaser Lenzing Aktiengesellschaft. The fibers “Avril” and “Hochmodul 333” are well introduced in the textile trade and are gaining increasing interest. Their well-balanced properties and good strength combined with a medium range elongation to break and a high but not overexaggerated modulus give them their good performance. Parallel to the development of the high wet modulus fibers, Tachikawa in Japan developed a spinning technique for high modulus fibers based on the spinning of viscoses with a high degree of xanthation and high viscosity into spin baths of very low acid and salt concentration applying high stretch to the resulting xanthate gel filaments. This technology gained wide interest throughout the world especially in France. Fibers spun with this technology were marketed under the general term “Polynosics.” Their benefits were high strength, elongation to break below 11%, low water swelling, very high modulus under dry and wet conditions, and good resistance against alkali in which polynosic fibers are somewhat superior to high wet modulus fibers. However, polynosic fibers have a very expressed fibrillar structure and tend much more to defibrillation than the high wet modulus types. These developments have also initiated substantial improvements of other types of regenerated cellulose fibers. The scale of such fibers is today a very diversified one and also cellulose fibers can be designed especially to meet end-product requirements. I n Table I V we have listed the wide variety of regenerated cellulose fibers the industry can produce and offer today. This summary illustrates the wide range of properties these fiber types cover, namely tenacities in the conditioned state from 2 g/denier up to over 7 g/denier and in the wet state from 1.2 g/denier up to over G g/denier. I n addition to this, we have added in this listing also the major structure characteristics of the various types of regenerated cellulose fibers mainly responsible for their properties. It illustrates that the cellulose fiber industry has learned to produce fibers from longer cellulose molecules up to over 500 glucose units long, and to alter by means of changes in viscose characteristics, by applying modifiers and spin bath additives, by adjusting spin bath composition, and by optimizing spinning conditions structure characteristics, such as the length of the morphological units forming the network of the fiber structure, the degree of order, and the alignment of the structure elements along the fiber axis.
TABLE IV.
STRUCTURE AND PROPERTIES OF VARIOUS REGENERATED CELLULOSE FIBERS (12)
Fiber type
DP
f?
Tensile strength, g/den Cond. Wet
Breaking elongation, yo Cond. Wet
Viscose fibers Normal Medium tenacity
290
95
0.79
0.312
2.21
1.17
26.9
28.5
295
80
0.66
0.356
3.16
2.07
15.5
25.5
High tenacity
285
77
0.69
0.358
3.82
2.92
22.3
30.3
HWM American origin
440
115
0.67
0.495
4.19
2.86
11.2
13.2
Hochmodul 333
360
99
0.70
0.458
4.15
2.73
13.5
16.0
Polynosic, elder type
500
172
0.74
0.538
3.38
2.41
7.0
9.9
Polynosic, newer type
490
130
0.72
0.520
4.25
3.00
10.2
12.0
290
97
0.66
0,421
3.36
2.26
10.0
18.3
Viscose tire yarn Low tenacity
Medium tenacity
340
93
0.76
0.416
4.14
3.11
11.3
26.3
High tenacity
500
70
0.66
0.409
5.32
4.21
10.9
31.4
Meryl
490
124
0.76
0.571
5.83
4.66
6.7
7.8
Fortisan
310
120
0.85
0.712
8.55
6.78
7.0
7.0
High Wet Modulus vs. Polynosic Fibers T h e development efforts in the man-made cellulose fiber industry in Europe were also influenced in the past years by some kind of tug of war whether to concentrate on the high wet modulus or the polynosic type. It seems to us worthwhile to analyze the properties of these two fiber types from our knowledge of the relations between fiber structure and properties. From the work of many scientists over the past 50 years the fiber structure can be considered, as shown by Figure 3, to be, in a simplified manner, a network of morphological units formed by the aggregation of fibrils and interlinked either by fringing molecular strands or isolated fibrils. From extended studies performed during the past 10 years, we could show (7, 9, 77, 72) that the basic fiber properties such as tensile strength and specific extensibility can be expressed by defined relations with structure characteristics (Table V). With the use of Table V, let us take a closer look a t the benefits and the shortcomings of high wet modulus and of polynosic fibers. T h e tensile strength in the conditioned state (Table VI) is determined b y the length of the macromolecules forming the fiber and the length of the morphological units (DP,) in accordance with the expression 1/DP, - 1/DPas wellas by the degree of orientation expressed by the square of ft and by the degree of order expressed by the crystallinity index, CrI. T h e product fo these three parameters is in good relation to the actual tensile strength. The square root of the orientation factor f T is a good measure of the relative reduction in tensile strength on wetting the fibers. These values also demonstrate that although the cellulose molecules are much longer, the degree of crystallinity is higher, and the orientation is better in the case of the polynosic fiberstheir tensile strengths are lower or only just the same as
Figure 3. Models of jiber structure A = Fringe micellar structure B = Fringe jbrillar structure
VOL. 6 2
NO. 3 M A R C H 1 9 7 0
9
those of the high wet modulus fibers-explained by the relatively long morphological units causing the number of molecular breaks in the interlinking areas for a given molecule length being higher. The figures in Table V I show also that newer modifications of Polynosic spinning reducing the length of the fiber building stones have led to a substantial improvement in strength. T h e larger the morphological units forming the network of the fiber structure so fewer are the number of interlinkages per unit surface area and so all the more easily will an abrasive action defibrillate the fiber. I t is
TABLE V. RELATIONS BETWEEN STRUCTURE AND PROPERTIES O F CELLULOSE FIBERS
I 1000/DP,
-
1000/DP
.- 1
DP,
E. wet T.S. wet 1 1000/DP,
- 1000/DP
. - 1. DP,
1 f,
our opinion that the long morphological units are the cause of the brittleness and of the lower abrasion resistance of polynosic fibers as illustrated by the figures given here. This deficiency has caused polynosic fiber manufacturers a lot of headaches and forced them to extensive development work which so far has not yet brought the solution. I t is our feeling that only a reduction in the length of the morphological units coming closer to the structure of the high wet modulus fibers will bring the intended improvement. Such changes would furthermore bring the effect of the longer cellulose molecules into better play justifying the difficulties in handling spinning solutions of remarkable higher viscosity. Also the elongation properties, the wet modulus, and the alkali sensitivity (Table VII) can be explained on the basis of structure data. Here the polynosics have advantages over the high wet modulus fibers. Their high degree of orientation and the bulkier morphological units more than balance the adverse effect of the lower degree of interlinkage of the structure network giving the polynosics their lower specific extensibility, their higher wet modulus, and their more expressed alkali stability. The advancement made in altering structure of viscose fibers to achieve lower water sensitivity is also illustrated by Figure 4 which shows the relation between improvement of structure and decreased water retention. Whenever today the high wet modulus fibers seem to have taken the lead over the polynosics, it is only due to the shortcomings of the latter with respect to wear resistance. I t is our conviction from the structureproperty considerations just presented that by steady development work aiming for a more interknitted structure, as already verified in high wet modulus fibers, and by maintaining a t the same time the higher degree of order and of orientation characteristic for today’s polynosic a good symbiosis between the two viscose fiber types should be achieved, bringing us closer to a more general accepted man-made cellulose fiber. New Fields of Application
Figure 4. Injuence of the degree of order and the degree of orientation on the water retention of various regenerated cellulosejbers ( 6 ) Normal viscose staplejber Viscose tire yarn H M = High wet modulusjiber Po = Polynosicjber 10
Tx
=
T7
=
M = Meryl F = Fortisan B w = Cotton
I N D U S T R I A L AND E N G I N E E R I N G CHEMISTRY
The future of man-made cellulose fibers, however, will not only depend on new and improved fibers for the textile trade. I t is a fact, as illustrated by the figures in Table VI11 ( 7 ) on the consumption of man-made fibers in the main end-uses for 1964-1966 in Western Europe and in the United States that the share of natural and man-made cellulose fibers in various end-uses is constantly decreasing. Efforts to open new fields of application are necessary to keep this trend under control and to replace losses. The high wet modulus fibers and the polynosic fibers have the potential to open new fields of application. Their stress-strain properties in the conditioned and in the wet state are closely matching those of cotton and of synthetic fibers. This makes them good blending partners. Blends of high wet modulus fibers or of polynosic fibers with cotton allow replacement of expensive combed cotton and better fabric uniformity. Blends with synthetic fibers have, for the textile trade, the incentive of
TABLE VI.
RELATIONSHIP BETWEEN STRUCTURE AND TENACITY OF VARIOUS REGENERATED CELLULOSE FIBERS Relative Tensile wet Product strength, strength, CrI ( 3 ) [(7-3)] g/den fioJ (4) %
AlOOO/ Fiber type
1000/DP, 1000/DP
Normal viscose fiber High wet modulus, Americanorigin Lenzing H M 333 Polynosics Elder type Newer type
TABLE V I I.
DP ( I )
fr2
(2)
10.30
3.45
6.85
0.099
0.79
0.53
2.21
0.559
50.2
8.70
2.28
6.42
0.245
0.67
1.05
4.19
0.704
68.5
10.10
2.78
7.32
0.210
0.70
1.07
4.15
0,677
65.8
5.80
2.00
3.80
0.290
0.74
0.82
3.38
0.733
71.3
7.50
2.04
5.46
0.270
0.72
1.06
4.25
0.722
70.5
RELATIONSHIP BETWEEN STRUCTURE AND ELONGATION PROPERTIES AND ALKALI SOLUBILITY OF VARIOUS REGENERATED CELLULOSE FIBERS
-
f,,O.S
(+) (7)
Fiber type
2
10 -
1000 -
18% Product Alkali (1 ) (2). (3) Specific extensibility, Wet solubzw % ElT.S* modulus, bility, ( 7-4) Dry Wet p/den yo
.
1 -
(21
Normal viscous fiber
0.622
1.46
10.3
3.18
9 . 4 [29.7]
12.9
[24.3]
3.8
8.3
High wet modulus American origin Lenzing HM 333
0.177 0.228
1.56 1.36
8.7 10.1
2.02 2.18
2.4 [4.6] 3 . 1 [6.8]
3.2 3.9
[4.6] [5.8]
14.5 12.5
3.7 3.4
Elder type
0.134
2.53
5.8
1.86
2 . 0 [3.7]
2.9
[4.1]
25.2
3.5
Newer type
0.148
1.83
7.5
1.92
2.0
[3.9]
2.7
[4.0]
27.0
3.1
Polynosics
TABLE V I I I .
FIBER CONSUMPTION I N M A I N END USES, 1964-1966 (in %) Man-made fibers Cellulosics
Areaof application Wear
Home furnishings
Industrial uses
Tire yarn
Share in total consumption
Year
Cotton EU USA
Wool Eu USA
Yarn Eu USA
Staple ’ EU USA
Synthetics Yarn Staple Eu USA Eu USA
1964
35.6
58.2
24.8
9.5
9.1
9.4
10.8
7.7
10.8
7.7
7.0
9.6
1965
34.8
54.8
24.6
9.3
9.2
9.0
11.3
6.2
11.7
8.3
8.4
11.9
1966
33.6
53.2
24.0
9.3
8.9
8.9
9.9
6.1
13.4
8.8
10.2
13.7
1964 1965
51.9 50.1
53.6 52.0
17.0 15.9
5.9 5.1
3.4 4.1
5.1 4.9
20.0 19.9
16.9 16.3
3.0 4.0
9.1 10.4
4.7 6.1
9.4 11.3
1966
49.1
51.2
16.4
4.8
3.7
4.3
17.9
15.9
5.0
11.2
7.9
12.6
1964
68.7
75.3
2.8
1.1
4.1
8.3
7.2
3.8
15.7
9.1
1.5
2.4
1965
65.1
72.4
3.4
1.0
4.1
8.7
8.6
3.3
16.8
12.4
2.0
2.2
1966
63.2
70.6
2.5
1.1
5.4
9.1
7.0
3.5
18.9
13.8
3.0
1.9
1964 1965 1966 1964
9.3 8.3 8.2 41.3
2.5 2.0 1.7 53.3
...... ......
... ...
8.8
49.8 52.9 61.5 10.6
...
13.8
10.3 13.1 14.4 9.1
...
7.0
47.7 45.1 36.8 10.2
...
20.1
80.3 78.5 77.3 10.2
5.6
8.5
1965
40.1
52.2
19.2
6.7
10.9
10.1
13.1
9.1
9.9
11.8
6.8
10.1
1966
38.9
50.9
19.1
6.3
10.6
9.5
11.5
9.0
11.5
12.9
8.4
11.4
. . . . . .
... ...
VOL. 6 2
NO. 3
...
MARCH 1970
11
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I I I 67-55-40 PE- 0 ‘10 33-§0.60-HM333-100- HM333-50-30 0 0 Cotton 50 80 -inn
- - I
-
cellulose fibers for paper and felt reinforcement. Also this calls for concentrated development work to supply products easily separating in stock preparation but giving good fiber-to-fiber bonding in the end product. As you all know there is an ever-increasing demand for flameproof fibers coming through legislative public security measures from governments throughout the world concerning nonflammable textiles. Although, we are of the opinion that, apart from the necessity of such measures, the economic volume for flameproof fibers will develop only a t a slow pace and that there will be difficulties in convincing the consumers and in creating potential markets. However, large fiber producers like Chemiefaser Lenzing AG cannot stand aside. For this reason we, like other companies throughout the world, have started a very substantial development effort toward the goal of flameproofing viscose fibers. Outlook
Wash & wear treated Figure 5. Tensile strength ( b ) , abrasion resistance ( c ) , water retention ( a ) , and creaxe recovery angle ( d ) of blended fabrics from Hochmodul 333 and polyester and from Hochmodul 333 and cotton (in each of the two series the highest value of the corresponding property is designated as 700%)
lower production costs and give the textiles better wearing comfort. Fabrics and knits made from blends of 70y0 polyester fibers and 3073 high wet modulus or polynosic fibers or from similar blends with polyamide fibers are already well accepted by the textile trade. For some years we have been aware of the benefits of these blends advertising the use of textile goods made from 7oy0high wet modulus and 30y0polyester fibers, or from 809;b high wet modulus and 20y0high modulus polyamide fibers. We call these blends “Hochmodul 333 SV” (SV = synthetically reinforced), so far they have been made with our high wet modulus fiber. The goal we believe reached in this development was to produce goods having tensile properties and wear resistance similar to nonresin-treated cotton and wash-wear characteristics similar to resin-treated cotton goods. The results of corresponding investigations ( 4 ) shown in Figure 5 demonstrate that these synthetic reinforced goods comply with the set goal. Blend fabrics of this nature are being introduced today for several end-use applications, such as sport shirts, work clothing, and others. Everywhere new stimulus for man-made cellulose fibers is coming from the fast development of the nonwoven field. The industry manufacturing dry-laid nonwovens is rapidly expanding and consumes increasing amounts of man-made cellulose fibers. This brings new problems for the fiber industry, such as finding a proper finish to allow a good felt formation but giving enough fiber bonding for high production speeds. Aside from this, manufacturers of paper and of wet-laid nonwovens show more and more interest in short-cut regenerated 12
l N D U S T R l A L A N D E N G I N E E R I N G CHEMISTRY
All in all, we strongly believe in the future of manmade cellulose fibers. This future will be-as is the case in all fields of industry-a never-ceasing struggle to be u p to date and with topmost efficiency. The “centers of gravity’’ will change-sometimes financial problems will be taking our time and attention, sometimes new development tasks will be on the top of the list, such as today’s efforts of all fiber manufacturers to produce a nonflammable fiber. Nevertheless, it will be necessary always to work on: -Establishing rational unit capacities -Always keeping up to date in equipment, methods, and products --Increasing productivity through rationalization and automation -Lowering production costs -Establishing raw material self-sufficiency -Never-ceasing efforts for process and product improvement -Diversifying through development of new products and product application Aside from this, it is our belief that fiber making calls increasingly for a solid and strong background in a large, diversified, and well-integrated company. REFERENCES (1) Annual reports of the International Rayon and Synthetic Fibers Committee (CIRFS) 1967, 1968, and 1969. (2) C o x N. L., E. I. du Pont deNemours & Co. U. S . Patents 2 536 014 2,535,044, and2,)5’35,049 (12/26/1950); cf. CA, 45,2207i: 26G9c, and 267bb (l95i). (3) Goetze, K., in “Chemiefasern nach dem Viskoseverfahren,” Springer Verlag, Berlin-Heidelberg-New York, 1967, Chap. I , pp 3/4. (4) Herzog, XV., “Einsatzmoslichkeiten von Hochmodul 333,” Lenringer B e r . , 27, 23-7 (May 1969). (5) Kraessig, H., “Betrachtungen zum Problem der Beziehungen zwischen Faserstruktur und Fasereigenschaften,” Texlilueredlung, 4 (l), 26-37 (1969). (6) Kraessig, H. “Die besonderen Eigenschaften von Hochmodul 333 in ihrer Beziehung zur baserstruktur,” Lenringer Ber., 27, 5-11 (Mai 1969). (7) Kraesaig, H., “Der Strahlenabbau der Zellulose und sein Einfluss auf die Festigkeit von Zellulosefasern,” Das Papier, 21 (10.4), 629-35 (1967). (8) Kraessig, H “Struktur und Eigenschaften von Viskosefasern,” Chemiefasern, 10, 821-30 (1%7). (9) Kraessig, H., “Struktur und Eigenschaften von Viskosefasern,” ibid., 17 (lo), 821-30; LenningerBer., 24,66-82 (1967). (IO) Kraessig, H., unpublished work. (11) Kraessig H Kappner, W. “The morphological units in cotton linters,” Makromol. &hem’,: 44/46, 1-7 (1661). (12) Kraessig, H., and Kitchen, W , “Factors influencing tensile properties of cellulose fibers,’’J. Polym. Sci., 51, 123-72 (1961).
