Content uploaded by Anders Persson
Author content
All content in this area was uploaded by Anders Persson on Oct 25, 2017
Content may be subject to copyright.
Original article
Textile qualities of regenerated cellulose
fibers from cotton waste pulp
Stina Bjo
¨rquist
1
, Julia Aronsson
1
, Gunnar Henriksson
2
and Anders Persson
1
Abstract
Cotton is not the answer to meet the rapidly growing demand for textile fibers. Wood-based regenerated cellulose
fibers are an attractive alternative. Since wood is a candidate to replace fossil raw materials in so many applications of the
circular economy, other sources need investigation. Cotton linters work in the viscose process – can cotton waste be
used to make dissolving pulp? We describe the textile qualities of lyocell fibers from (i) pure cotton waste pulp and
(ii) blending with conventional dissolving pulp. The staple fibers were tensile tested, yarns spun and tensile tested and
knitted, and tested for shrinkage, water and dye sorption, abrasion resistance, fuzzing and pilling, staining and fastness.
TENCELÕstaple fibers and off-the-shelf TENCELÕyarn were used as references. The results show that the two study
fibers had tenacity and an E-modulus that exceeded the staple fiber reference. Also, the study yarns were at least as good
as the spun reference yarn and the commercial off-the-shelf yarn in terms of wet tenacity. Single jerseys made from the
study yarns shrunk less upon laundering, which is surprising since they could absorb at least as much water at a
comparable rate as the references. Dyeability, staining and color fastness, durability and pilling tendency showed that
the two study fiber tricots performed at least as good as the references. This study suggests that cotton waste is a
promising candidate for special grade pulp to suit niche regenerated fiber products or to spice up conventional wood-
based dissolving pulp.
Keywords
cotton waste pulp, staple fiber, circular economy, environmental sustainability, spinning, fabrication
As textile consumption has been growing and continues
to do so, the demand for fiber supply grows too. Based
on global population and wealth increase, forecasts
suggest that the textile fiber demand will grow
from 87 Mton (2014) to 240 Mton by the year 2050.
1
Cotton production has leveled off at about 25 Mton,
1
and due to sustainability reasons cannot increase sig-
nificantly. The increasing demand is mainly met by syn-
thetic fibers; in particular, polyester fiber production is
growing rapidly. However, the comfort properties of
cotton are not matched by polyester. Hence, there is
an ever-growing need for fibers with comfort qualities
that resemble cotton, that is, cellulose-based fibers.
Furthermore, there are sustainable arguments against
the increasing use of synthetic textile fibers; besides
that, they mainly are made of non-renewable
raw-materials – with uses that contribute to climate
change,
2
the use of synthetic fibers makes a significant
contribution to the increasing environmental problems
of persistent micro-plastics.
3
Besides cotton, natural cellulose fiber production vol-
umes are small. Even if there is a huge potential to use
agricultural waste
4
or increase the cultivation of natural
fibers, such as bamboo, flax, hemp and ramie, it would
take a major shift in global-scale agriculture politics to
generate a significant contribution in comparison to
regenerated cellulose fibers. In 2014, approximately
1
Swedish School of Textiles, University of Bora
˚s, Sweden
2
Re:newcell, Birger Jarlsgatan, Stockholm, Sweden
Corresponding author:
Anders Persson, Swedish School of Textiles, University of Bora
˚s,
Skaraborgsva
¨gen 3, Bora
˚s, 50190, Sweden.
Email: anders.persson@hb.se
Textile Research Journal
0(00) 1–8
!The Author(s) 2017
Reprints and permissions:
sagepub.co.uk/journalsPermissions.nav
DOI: 10.1177/0040517517723021
journals.sagepub.com/home/trj
5 Mton of regenerated staple fibers (4.6 Mton) and fila-
ment yarns (0.44 Mton) were produced.
1
Wood is the
dominant raw material for dissolving pulp, but many
other sources are plausible. In a future circular econ-
omy, non-renewable resources must be replaced and
wood would be one of the main raw materials in a bioec-
onomy. Wood could be the chemical feed stock for vari-
ous chemical raw chemicals. This could threaten the
abundantly available supply of cellulose for dissolving
pulp. In addition, it takes a lot of energy and chemicals
to produce dissolving pulp from wood. Thus, more
accessible cellulose sources with a lower ecological foot-
print of the ready-made fibers need to be considered.
Cotton linters have long been utilized as a cellulose
source in the viscose process. It is therefore logical to
investigate the applicability of cotton waste as a raw
material for dissolving pulp. This opportunity has
been appreciated by the Mistra Future Fashion program
that investigates how to make dissolving pulp from
cotton waste.
5,6
Also the Dutch company Saxcell,
7
the
American company EvRnu
8
and the Swedish company
Re:newcell
9
show similar objectives. Both Saxcell
7
and
Haule et al.
10–12
have taken another step by utilizing
their cotton waste pulps to make fibers. Saxcell claim
to have succeeded both by the viscose and lyocell pro-
cesses,
7
whereas Haule et al.
10–12
utilized the lyocell pro-
cess. In a recent press release, Lenzing
13
announced the
launch of Refibra
TM
, a version of TENCELÕfiber made
out of cotton scrap and wood pulp. Researchers from
Aalto University reported that they used cotton waste
pulp blended with dissolving pulp in their Ioncell pro-
cess.
14
According to a recent paper by Schuch,
15
the
Aalto activities were conducted under the Horizon
2020 Trash-2-Cash project umbrella where also the
Finish research institute VTT was enrolled in the prep-
aration of cotton waste. Even if activities on cotton
waste pulp and the properties of their regenerated cellu-
lose fibers have been reported, no studies on the textile
qualities of such fibers for textile manufacturing have
been published. In this study, staple fiber and yarn ten-
sile properties of lyocell fibers were investigated. The
quality of the finished textile, as knitted single jersey
samples, regarding the important properties of shrink-
age, wicking, dyeability, staining and color fastness, and
abrasion and pilling resistance were evaluated and com-
pared to appropriate references. Both fibers manufac-
tured from 100% cotton waste pulp fibers and fibers
from 90/10 juvenile birch/cotton waste pulp blends
were included in this study.
Methods
This section specifies the utilized materials, how they
were made into textile structures, treated and
characterized.
Materials
Lenzing AG kindly provided 1.3 dtex and 38 mm long
commercially available TENCELÕstaple fibers, from
here on denoted TENCELÕ.
Also, a ready-made commercial 25 tex ring spun
TENCELÕyarn was used as reference. A Frank-type
ku-212 twist tester operated in accordance with ISO
2061:2015 was used to determine its mean twist
number to 490 tw/m. swas 32 tw/m and CV was
6.6%. This yarn is from here on denoted RefYarn.
Vibroskop was used to determine its TENCELÕfiber
titer to 1.78 0.20 dtex (mean s).
Fiber spinning. Textile pulp, prepared from post-consu-
mer denim garments by the Swedish company
Re:newcell in a process that removed color, adjusted
the degree of polymerization of the cellulose and
increased the chemical reactivity was the textile pulp
used for this study. The lyocell staple fibers were regen-
erated from (i) 100% post-consumer denim waste pulp
and (ii) 90% birch-based Kraft dissolving pulp and 10%
cotton waste pulp. The 10% addition of cotton waste
was based on considerations of solubility, rheology and
material management. Both fibers and their yarns are
from here on denoted (i) textile pulp and (ii) birch/textile
pulp, respectively. The pulps were then processed with
dry–wet technology spun into 1.7 dtex and 38 mm long
staple fibers by direct dissolution in aqueous 4-methyl-
morpholine 4-oxide, NMMO solution by the contract
laboratory; Thu
¨ringisches Institut fu
¨r Textil -
und Kunststoff-Forschung, TITK in Rudolstadt,
Germany. Cuoxam-DP’s and a-cellulose contents were
406 and 508, and 92.9% and 94.4% for cotton and birch
pulps, respectively. The spin dopes had a 13.2% dry
content and the zero shear viscosities were between 5.6
and 7.6 Pas at 85C, which was the temperature of the
nozzle. No finishing agent was added to the fibers.
Yarn spinning. Batches of 35.0 g staple fibers were manu-
ally opened and carded twice on a Mesdan-lab Felt
carder 337A, where the web was wound up on a
1.2 m circumference drum with a 90turn of the web
between cardings. After the second carding the webs
were rolled up to a 1.2 m long sliver that was sequen-
tially drawn in a Mesdan-lab Mini Stirolab 3371 into
rovings that were spun to yarn of 25 tex target linear
density. The spinning was conducted on a Mesdan-lab
Ring lab 2108A with a 90 mg traveler, Bra
¨cker AG90-4
SAPHIR. A series of 500, 650 and 750 twist/m was con-
ducted to find the minimum number of twists where the
mechanical properties leveled off. It turned out that
650 twist/m was a suitable setting for the targeted
25 tex yarns. The draft was in the range of 28.7–29.5
times and the spindle was run at 6400–6500 rpm.
2Textile Research Journal 0(00)
Knitting. Single jerseys were knitted on an 18 gauge
Camber Ltd International Velnit N.S. circular knitting
machine. Eighteen spools of yarn were utilized to feed
the machine.
Fabric area weight and shrinkage determination
Three 1 dm
2
pieces were cut from each undyed single
jerseys before and after the first laundering for area
weight determinations. Laundering was conducted at
40C in accordance with ISO 6330, program 5 a with
30 g of a commercial domestic liquid white wash deter-
gent [ICA Skona Vittva
¨tt, flytande]. The laundered
single jerseys were hung to dry in a drying cabinet for
30 min at 40C. Before weighing, all samples were con-
ditioned at (65 2)% relative humidity (RH) and
(20 2)C for at least 24 h.
Dyeing. Four single jersey samples, each 10.0 g, knitted
from each yarn type were dyed by reactive dye,
LevafixÕBrilliant Blue E-BRA Macrolat, concentra-
tion 1.0% by weight in relation to the fabric and 5%
NaCl concentration. The single jersey pieces were
folded, rolled and put into Pyrotex MB2 stainless
steel containers of 150 ml volume. Dyeing started at
room temperature and was heated by 2C/min to
60C. After 30 min, 3 g of NaOH was added to each
container, which was resealed and maintained for 1 h
at 60C and then left to cool to 40C, which took about
30 min. Each sample was individually rinsed in 1 l of
cold tap water followed by boiling in 1 l water with
3 ml Skona liquid white wash detergent for 1 min.
After another cold water rinsing, the single jersey sam-
ples were manually squeezed out, centrifuged for 30 s
and hung to dry in a drying cabinet at 40C for 30 min.
The samples were then stored for at least 24 h in an air
conditioned environment at 20 2C and 65 2% RH.
Tensile testing
Tensile testing concerned both staple fibers and yarns.
All samples were stored in an air conditioned environ-
ment, 20 2C and 65 2% RH, for at least 24 h
before tensile testing.
Fiber tensile testing. Twelve fibers of each kind were ten-
sile tested on a Vibroscop/Vibrodyn, Lenzing instru-
ment at 20 mm gauge length, with 20 mm/min
deformation rate and 100 mg pretension weight.
E-moduli were determined by curve fitting of the
linear part that followed the straightening of the crimp.
Yarn tensile testing. Tenacities of all yarns were tested in
accordance with ISO 2062:1993 on a Mesdan Tensolab
2512A/2512C electromechanical 3 kN tensile tester
equipped with 100 N load cell and pneumatic grips.
A gauge length of 250 mm, elongation rate of
250 mm/min and 0.5 cN/tex preload were applied.
Thirty samples were tested for each yarn category.
Statistical methods. Statistical analyses were carried out
for fiber and yarn tensile tests by one-way analysis of
variance (ANOVA) and Tukey simultaneous tests for
differences of means at the 95% confidence interval
level. Regarding the quality tests of the single jerseys,
the numbers of samples were too few to conduct any
statistical analysis.
Water sorption
The water sorption ability was assessed in accordance
with standard ISO 9073-12:2002. Three 55 mm diam-
eter circular pieces were cut from each single jersey
and weighed on a Sartoruis LP220P analytical balance.
The set-up consisted of a water filled beaker, on the
reset balance, connected by a siphon to a porous glass
plate where the sample was put under a 605 g soft-foam
covered dead weight. Sorption kinetics and saturation
were recorded as MAR,t
f
and DAC, respectively. MAR
is an acronym for Maximum Absorption Rate [g/s],
while t
f
[s] denotes that the absorbed mass variation
in the previous 5 s time period is lower than 1% of
the absorbed mass and DAC, Demand Absorbency
Capacity, is the ratio of the maximum absorbed mass
divided by the sample mass [g/g].
Dyeability
A calibration curve of absorbance at 594 nm wave-
length was established by concentrations of 12.5, 25,
50, 100 and 200 mg/l dye stuff in the dyeing bath, mea-
sured by the absorption spectrophotometer Datacolor
Check run in single scan mode. With this curve, the
post-dyeing residual dye stuff concentration in the
color baths could be determined. The calibration
curve had an R
2
of >0.999.
Staining and color fastness
Staining tendencies and color fastness of the single
jerseys were evaluated in accordance with SS-EN ISO
105-C06:2010.
Samples, cut to 10 cm 4 cm, sewn side-by-side to
multi-fiber strips along the 4 cm fringe, were prepared
for each single jersey. The sewn samples, put in sealed
stainless steel vessels together with 25 stainless steel
balls (0.9 g/ball) and 4 ml/l white washing detergent,
were washed at (60 0.2)C in a Gyrowash 815 for
30 min. After separation and rinsing in 1 l cold tap
water followed by centrifugation and drying in
Bjo¨rquist et al. 3
a drying cabinet for 30 min at 40C, two non-biased
observers independently assessed the color changes of
blinded multi-fiber strip samples compared to
unwashed reference strips according to the five-grade
gray–white scale SDL ATLAS G246B. Assessments
were made under D65-light in a light cabinet where
grade 5 meant no color change of the washed multi-
fiber strips.
The washed single jersey samples were compared to
unwashed reference single jersey of the same quality.
Also, the color fastness was assessed under D65-light
in a light cabinet independently by two non-biased
observers on blinded samples. Color changes were
graded according to the five-grade gray–gray scale
where 5 meant no color change compared to the
unwashed references.
Mean values of the graded samples in terms of stain-
ing and color fastness were calculated.
Abrasion resistance and pilling
The abrasion resistance was quantified on dyed single
jersey samples on a Martindale 2000 Abrasion tester in
accordance with ISO 12947-2:1998. Three samples of
each yarn type were abraded against a woolen cloth
until yarn breakage was visually observed and the
number of revolutions was recorded.
Pilling tendency was assessed intermittently by visual
inspection in a blinded manner of two non-biased
observers who independently graded the degree of pil-
ling in 0.5 increments. A Martindale 2000 Abrasion
tester fitted with the sample also as abradant, face to
face, with a dead weight of (595 7) g equivalent to
9 kPa pressure was applied on a total of three pairs of
samples. Samples were assessed after 125, 500, 1000,
2000, 5000 and 7000 revolutions.
Results and discussion
Fibers
In order to make really fine yarns that are both strong
and compliant, the staple fibers have to be strong and
fine. According to Table 1, the mechanical properties of
the study fibers were both statistically significantly
stronger (Tenacity) and stiffer (E-modulus) than the
reference TENCELÕfiber. In particular, fibers spun
from the mixed pulp source rendered exceptional
tenacity.
Haule et al.
10
airgap spun NMMO solutions made
out of (i) simulated post-consumer cotton waste by 50
repeated washing cycles of 152 g/m
2
plain cotton
weaves; (ii) the same weave that was first easy-care
treated and subsequently removed by acid–alkali
treatment and blended with 80% wood pulp; and
(iii) washed waste indigo dyed denim. They found tena-
cities of 48.7, 42.5 and 37.2 cN/tex for (i), (iii) and (ii),
respectively, and 34.7 cN/tex for a reference lyocell
staple fiber that they used. Furthermore, they registered
E-moduli that were about 50% higher for (i) and (iii)
than (ii) and the reference. Unfortunately, they did not
state what wood pulp they utilized. The tenacities of
the wood-based cotton waste blends came out very dif-
ferently: 54.7 cN/tex for the present study versus
37.2 cN/tex for the values reported by Haule et al.
10
;
while we report the highest molar mass for the birch/
textile pulp they reported their blend pulp,(ii), to have
about half the molar mass of the simulated post-
consumer textile pulp, (i).
Thus, it appears that the regenerated cellulose fiber
made from the textile pulp possesses very good mech-
anical properties. The question is why this is. The
explanation is most likely not that the cellulose chains
should have a higher degree of polymerization. From
the present data it is not possible to explain this, but
one can imagine at least two different explanations as
follows.
.The cellulose from the textile waste is purer than
the cellulose from dissolving pulps,
16
that is, it con-
tains less or no hemicellulose and this could give a
stronger interaction between the polymers in the
fibers.
.The cellulose could contain residues of pigments and
other chemical treatments covalent attached to the
chains. They could work as ‘‘hooks,’’ thereby
increasing the friction between cellulose chains and
thereby improving the chemical properties of the
regenerated fiber.
Yarns
As shown in Table 2, the pure textile pulp-based yarn
turned out to be statistically significantly stronger (ten-
acity) than the yarns we made from TENCELÕ
Table 1. Staple fiber properties given as mean s
Parameter Textile pulp Birch/textile TENCELÕ
Fineness [dtex] 1.65
a
0.21 1.65
a
0.17 1.32 0.10
Tenacity, dry [cN/tex] 46.9
b
5.5 54.7
a,e
5.6 39.9 2.5
Elong at break [%] 11.3
c
1.6 13.4
f
2.1 13.4 1.9
E-modulus [N/tex] 8.3
d
1.5 10.6
a,g
1.5 7.0 1.9
Superscripts a, b, c and d denote statistically significant difference from
TENCELÕfibers at adjusted P-values of 0.0001 or less, 0.0028, 0.0215
and 0.0467, respectively, while e, f and g denote statistically significant
differences between textile pulp and birch/textile of 0.0009, 0.0279 and
0.0032 P-values, respectively. All in accordance with Tukey outcomes.
4Textile Research Journal 0(00)
reference staple fibers. This goes both for the dry and
wet strength. It is striking how much less the tenacity
drops upon soaking for both study fibers compared to
the references. Haule et al.
10
also noted that their
cotton waste pulp-based fibers with the highest molar
mass were less sensitive to humidity. In both studies it is
the high-strength fibers that are less affected by
humidity.
According to Table 2, both studied fiber yarns dis-
play significantly lower elongation at break, both in
their dry and wet states, compared to the reference
fiber yarns. Considering the lower twist number of
RefYarn, its elongation to break should be higher.
Table 2 also shows that the tenacity data of the yarn
made during this study scattered to a high extent. This
is definitely according to expectations from our small-
scale lab spinning. The yarn index of quality displayed
in the second-to-bottom row of Table 2, which is the
ratio of the mean tenacity times the mean elongation at
break divided by the yarn linear density coefficient of
variation,
15
clearly illustrates the difference between the
commercial yarns and the yarns made we made.
Although all studied yarns were ring spun, it is fair to
claim that the conditions in the ring spinning varied
with the small-scale manufacturing compared to the
industrially manufactured RefYarn. Furthermore, the
twist multiple, TM, of the RefYarn indicates use in
knitted structures. According to Lawrence,
17
aTMin
the range from 2050 to 2550 is suited for hosiery,
whereas TMs of approximately 3300 are better suited
as weft yarns in weaves. Another significant factor may
have been that no spin-finish was applied on the studied
fibers.
It should be noted that the TENCELÕreference
yarn was made from finer fibers. The link between fine-
ness and strength of fibers transforming into yarn
strength was described by Simpson and Murray,
19
who found that the tenacity of 25 tex ring spun
cotton yarns increased with fiber fineness. Their views
suggest that the finer staple fibers of TENCELÕwould
render higher tenacity than the yarns from the courser
study fibers. However, the results from this study show
the contrary. As could be expected, Simpson and
Murray also found fiber strength to be an even more
prominent factor for yarn tenacity.
Single jersey area weight and shrinkage
upon laundering
Limited shrinkage, which is linked to water sorption
characteristics in warm water, is important in order to
accomplish high-quality single jerseys. Data on the
mass of 1 dm
2
samples cut from as-received single jer-
seys or cut from once laundered single jerseys are pre-
sented in Table 3. Due to the limited sample size, no
statistical significance analysis has been conducted but
a qualitative comparison shows at hand that textile
pulp single jersey shrunk the least while the commer-
cially available yarn, which also rendered less dense
single jersey from the beginning, shrunk the most.
Given the lower number of twists of the RefYarn that
also rendered a looser structure, as indicated by its
lower mass before laundering, it had a higher gain
upon laundering. Compared to the TENCELÕrefer-
ence, the study single jersey shrunk the least.
Water sorption
Yet another important textile quality is the single jer-
sey’s ability to absorb and transport humidity. This is
essential for comfort properties. Figure 1 shows the
absorption ability for the different single jerseys.
Surprisingly, it is the birch/textile-based single jersey,
made out of the strongest and stiffest fibers, that
Table 2. Yarn properties given as mean s. Index of quality according to Barella et al.
18
and twist multiple in
accordance with Lawrence
17
Parameter Textile pulp Birch/textile RefYarn TENCELÕ
Linear density [tex] 26.1 3.6 24.7 3.7 25.4 0.5 26.6 4.7
Yarn twist [tw/m] 650 650 490 650
Tenacity, dry [N/tex] 27.6 7.0 22.6
a
6.7 26.6
c
2.6 23.3
b
5.7
Elong at break, dry [%] 8.4 1.0 8.9 1.1 10.5
d,e
0.8 10.2
d,e
0.9
Tenacity, wet [N/tex] 23.1 5.6 22.3 5.4 18.1
f,g
3.0 16.5
d,e
3.9
Elong at break, wet [%] 10.2 1.1 10.5 1.0 11.7
d,h
1.5 12.8
d,e,i
1.3
Index of quality, I17 14 129 14
Twist multiple [tw/m tex
1/2
] 3321 3231 2467 3352
Superscripts a, b, d and f denote statistically significant difference from textile pulp at adjusted P-values of 0.0069, 0.0272, <0.0001 and
0.0003, respectively, while c, e, g and h denote statistically significant difference from birch/textile at adjusted P-values of 0.0489,
<0.0001, 0.0037 and 0.0007. Finally, superscript i denotes a statistically significant difference between RefYarn and TENCELÕat an
adjusted P-value of 0.0058. All in accordance with Tukey outcomes.
Bjo¨rquist et al. 5
stands out with a mean 4.5 times water DAC sorption.
The MAR, as shown in Figure 2, was highest for the
birch/textile single jersey. The saturation time, t
f
, was
also recorded but it is not shown graphically here.
Commercial TENCELÕsingle jerseys reached satur-
ation after about 26 s, while it took birch/textile
about 32 s and textile pulp and RefYarn single jerseys
both took about 37 s to level off. The limited number of
samples does not make it possible to conduct statistical
analyses and to draw solid conclusions. Hence, the dif-
ferences are merely qualitative. It needs pointing out
that neither of the study fibers had received spin-
finish or other additives, which are known to alter the
hydrophilicity of regenerated fibers. The difference in
twist between the RefYarn and the other three yarns
should also, to some extent, affect the hygroscopic
nature of the yarns given the interfiber capillary forma-
tion difference.
Dyeability, staining and color fastness
Dyeability quantified by the remaining dye stuff in the
color baths after 2 h immersion time showed virtually
unison values of 96.3–96.4% for all four single jerseys.
This is indicative of good dyeability. No measure-
ments regarding dye saturation was conducted
during the dyeing process. Results from the single
jersey staining tendency are shown in Table 4. While
the commercial RefYarn showed no tendency to stain
and the equally commercial TENCELÕfiber-based
single jerseys only stain wool, both study single jerseys
showed a noticeable yet modest staining tendency. The
color fastness data in Table 5 show that the textile
pulp single jersey is by far the most sensitive single
jersey among the four. The off-the-shelf RefYarn
had the best color fastness. Since neither the chemical
structure nor the ultrastructural properties of the
investigated fibers were investigated, there is no basis
for a discussion on the reasons behind the staining
tendency and color fastness variations among the dif-
ferent single jerseys.
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Texle pulp
Birch/Texle
RefYarn
Tencel
DAC [g/g]
Figure 1. Column heights and error bars represent the mean
and sof the Demand Absorbency Capacity (DAC) of the
various single jerseys in accordance with the legend.
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
Texle pulp
Birch/Texle
RefYarn
Tencel
MAR [g/s]
Figure 2. Column heights and error bars represent mean and
sof the Maximum Absorption Rate (MAR) of the different
single jerseys in accordance with the legend.
Table 3. Mass of single jersey samples given as mean s
Parameter Textile pulp Birch/textile RefYarn TENCELÕ
Before laundering [g] 122.7 2.7 117.9 7.3 99.0 3.5 112.7 2.8
After first laundering [g] 133.0 2.4 138.2 3.8 131.7 4.4 144.1 4.4
Gain after first laundering [%] 8.4 17.2 33.0 27.9
Table 4. Results from staining tests as judged by two
non-biased evaluators. A score of 5 represents no staining
Single jersey Diacetate Cotton Polyamide Polyester Acrylic Wool
Textile pulp 5 4.5 5 5 5 4.5
Birch/textile 4.5 5 4.5 4.5 5 4.5
RefYarn 5 5 5 5 5 5
TENCELÕ5 5 5 5 5 4.5
6Textile Research Journal 0(00)
Abrasion resistance and pilling
Data from Martindale abrasion resistance testing are
presented in Figure 3. Qualitatively, the birch/textile-
based single jersey was the most durable of the four.
As pilling is considered the Achilles of fibers made by
the lyocell process, it is essential to compare the study
single jerseys to the references. Figure 4 shows
how pilling evolved during Martindale testing and it
was apparent that the pilling rating did not stay con-
stant with the number of cycles. Except for the birch/
textile, which according to Figure 4 appear to increase
the pilling degree for every assessment, the general
trend seen in Figure 4 is that pilling intensity went
through a minimum during the course of the 7000
cycles. The number of cycles to these minima was indi-
vidual for each single jersey. Notice that neither spin-
finish nor other additives were added to the two study
fibers or single jerseys. The lower number of twists for
the commercial RefYarn should make it more sensitive
to abrasion and potentially also alters its pilling
characteristics.
Conclusions
Dry–wet spinning of pure cotton waste-based pulp,
here denoted textile pulp, and blended with birch-
based dissolving pulp in the ratio of birch/textile
90/10, rendered fibers with both statistically signifi-
cantly higher tenacities and higher E-moduli than a
commercially available TENCELÕfiber.
Yarns were ring spun out of the two study fibers and
the reference TENCELÕfiber and compared with a
25 tex off-the-shelf TENCELÕyarn. The numbers of
twist of our yarns were higher than for the commercial
yarn. Mechanically, the pure textile pulp yarn had stat-
istically significantly higher dry tenacity than the yarn
we made from the TENCELÕfibers. The wet tenacity
of both study fiber yarns turned out to be statistically
significantly higher than the two reference yarns even if
the lab-scale spinning rendered yarns of much lower
quality index than the commercial reference yarn.
Single jerseys knitted from the study yarns shrunk less
than both the herespun TENCELÕfiber yarn and the
off-the-shelf TENCELÕyarn.
The single jerseys were utilized to quantify other tex-
tile qualities of the different materials in terms of
shrinkage, water carrying capacity, water transport
rate, dyeability, staining and color fastness, durability
and pilling tendency. Besides the poorer color fastness
of the fabric based on cotton waste textile pulp, the
general picture is that the two study fiber single jerseys
performed as good as the references.
The question is how textile pulps shall be used in the
most rational way. One way is, of course, to use them
for making textiles of high quality, but another possi-
bility is to mix textile pulps with conventional dissol-
ving pulps based on wood, thereby increasing the
2
4
6
8
10
12
14
16
18
20
Revolutions
0
000
000
000
000
000
000
000
000
000
000
Text
Birch
RefYa
Ten
ile pulp
/Texle
rn
cel
Figure 3. Abrasion resistance represented as the mean
number of revolutions before yarn breakage was recorded in the
knitted structure. Column height represents mean and the error
bars s.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
125 500 1000 2000 5000 7000
Pilling rating
Revolutions
Texle pulp
Birch/Texle
RefYarn
Tencel
Figure 4. Pilling rating values of single jersey knitted from yarns
according to the legend. Columns represent means and the error
bars s.
Table 5. Results from color fastness tests as judged by two
non-biased observers. A score of 5 represents no color change
Textile pulp Birch/textile RefYarn TENCELÕ
Observer 1 3.5 4.5 5 4
Observer 2 3 4.5 4.5 4
Mean 3.2 4.5 4.8 4
Bjo¨rquist et al. 7
mechanical properties. Eventually, this may be an
economical decision.
Acknowledgments
Lenzing AG is gratefully acknowledged for providing the
TENCELÕstaple fibers. We are also grateful to TITK,
Thu
¨ringisches Institut fu
¨r Textil - und Kunststoff-Forschung,
whose expertise in cellulose dissolution and spinning enabled
this study. At Swerea IVF, Doctor Carina Olsson was kind
enough to conduct the staple fiber tensile tests. Lena-Marie
Jensen at Smart Textiles, University of Bora
˚s, is also
acknowledged for her organizational support.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with
respect to the research, authorship and/or publication of this
article.
Funding
The authors disclosed receipt of the following financial sup-
port for the research, authorship, and/or publication of this
article: We would like thank Vinnova, the Swedish Agency
for Innovation Systems, as the main sponsor of the Textiles
Back to Textiles project that this study was part of.
References
1. Trends in global and regional man-made fibre production.
Text Outlook Int 2016; 178: 1–225.
2. Veland S and Lynch AH. Scaling the anthropocene: how
the stories we tell matters. Geoforum 2016; 72: 1–5.
3. Cole M, Lindeque P, Halsband C, et al. Microplastics as
contaminants in the marine environment: a review. Marine
Pollut Bull 2011; 62: 2588–2597.
4. Dungani R, Subyakto KM, Sulaeman A, et al.
Agricultural waste fibers towards sustainability and
advanced utilization: a review. Asia J Plant Sci 2016; 15:
42–55.
5. Palme A, Idstro
¨m A, Nordstierna L, et al. Chemical
and ultrastructural changes in cotton cellulose induced
by laundering and textile use. Cellulose 2014; 21:
4681–4691.
6. Palme A, Theliander H and Brelid H. Acid hydrolysis of
cellulosic fibres: comparison of bleached Kraft pulp,
dissolving pulps and cotton textile cellulose. Carbohydr
Polym 2016; 136: 1281–1287.
7. Luiken A and Bouwhuis G. 18 - Recovery and recycling
of denim waste A2. In: Paul R (ed.) Denim: Manufacture,
finishing and applications. Woodhead Publishing Series in
Textiles, Elsevier, 2015, pp.527–540.
8. Gullingsrud A. Fashion fibers: Designing for sustain-
ability. New York, USA: Bloomsbury Publishing Inc.,
2017.
9. Lindstro
¨m M and Henriksson G. Renewcell Lux S. A. R.
L., assignee. Regeneration of cellulose. Patent
US20140343270A1, USA, 2014.
10. Haule LV, Carr CM and Rigout M. Preparation and
physical properties of regenerated cellulose fibres from
cotton waste garments. J Clean Prod 2016; 112:
4445–4451.
11. Haule LV, Carr CM and Rigout M. Investigation into
the supramolecular properties of fibres regenerated from
cotton based waste garments. Carbohydr Polym 2016;
144: 131–139.
12. Haule LV, Carr CM and Rigout M. Investigation into
the removal of a formaldehyde-free easy care cross-link-
ing agent from cotton and the potential for subsequent
regeneration of lyocell-type fibres. J Text Inst 2016; 107:
23–33.
13. Lenzing AG. RefibraTM fiber – Lenzing’s initiative to
drive circular economy in the textile world. Lenzing AG,
2017.
14. Asaadi S, Hummel M, Hellsten S, et al. Renewable high-
performance fibers from the chemical recycling of cotton
waste utilizing an ionic liquid. ChemSusChem 2016; 9:
3250–3258.
15. Schuch AB. The chemical recycle of cotton. Revista
Produc¸a
˜o e Desenvolvimento 2016; 2: 64–76.
16. McCall ER and Jurgens JF. Text Res J 1951; 21: 19–21.
17. Lawrence CA. Fundamentals of spun yarn technology.
Boca Raton, FL; London: CRC Press, 2003, pp.1–52.
18. Barella A, Vigo JP, Tura JM, et al. An application of
mini-computers to the optimization of the open-end-spin-
ning process. Part I: consideration of the case of two
variables. J Text Inst 1976; 67: 253–260.
19. Simpson J and Murray MF. Effect of cotton fiber fine-
ness and strength on mechanical processing and open-end
spinning and yarn properties. Text Res J 1978; 48:
270–276.
8Textile Research Journal 0(00)
