Moisture management in fabrics

2. 2
Introduction:
If synthetic fiber, such as polyester, has more hydrophilic properties, especially
water/perspiration absorbency with wash-fast resistance, its use will further broaden.
Meanwhile, cases of cellulosic fiber, which originally possesses great water absorption,
turning water-repellent have become frequent recently, resulting from the use of complex
finishing composites (e.g. fixing agents, resins, softening agents etc) inhibiting the
hydrophilic properties of fiber.
Superior hydrophilic properties (water/perspiration absorbency) will allow varieties of fiber
materials, knits, wovens and industrial materials a broader scope of use. Gingham shirting,
bedding, knits, toweling, sportswear, casual wear, upholstery, sheeting and table linens are
some examples.
Here, the use of a ‘durable, water-absorbent & quick-dry SR finishing agent’, i.e. a fiber
finishing auxiliary capable of a) inhibiting degradation of hydrophilic properties due to
repeated home laundering, b) repelling oil and c) soil release (SR) during laundering, will
result in the creation of products of high practicality with a broader scope of use.
While the traditional rendering of oil/water-repellent 'SR', for which fluorocarbon polymer
is mainly used, stood for the effect of inhibiting oil adhesion, the practical meaning is rather
soil-repellent, soil-proofing, soil-guard or soil-resistance.
Originally, the idea of SR finishing was to impart some hydrophilic properties to highly-
hydrophobic polyester in order to prevent soil adhesion, especially oil stains, and to produce
a fiber surface with oil-release properties.
When hydrophobicity is high, the charging tendency becomes strong, soil adhesion more
likely and, ultimately, a stain-darkened material will result. Oil stains also adhere heavily,
which makes their removal and washing off difficult.
Taking the above points into consideration, the surface treatment with sufficient hydrophilic
properties will bring out the following advantages:
Water/perspiration absorbency
Easy oil removal, improved SR and OR (oil-release) properties
Improved anti-static properties
The use of polymers and chemical compounds other than fluorine-based polymer can also
be considered for water absorbent SR. In addition, since the kind of oil staining and the oil
concentration often vary, oil-releasing results will differ.
Thus, the application of many different types of hydrophilic stain-resistant agent should be
taken into consideration.
This article will deal with two unique products, developed by L.N. Chemical Industries with
a view to the multiple purposes mentioned above.

3. 3
Quest-DCO: Water-absorbent, quick-dry, wash-fast anti-staining SR (OR) and softener for
polyester
Quest-CSR: Durable water-absorbent anti-static SR, hydrophilic improver for all kinds of
fiber, including cotton and polyester
The features of the two products are compared in Table 1.
Textile-finishing polymers are mainly concerned with the development of such products,
however, it is also important to know from what chemical substances we need to select an
oil-repellent component and an oil-releasing component. The use of a hydrophilic type as
the main chain and the selection of copolymerizing, bond-reacting groups from hydrophilic
groups will be called into account, as well as the addition of a water-absorbent and a cross-
linking groups. A functional group (polymer) formed in this manner needs to be
predetermined to act as a stronger cross-link with or a strengthener of adhesion to the fiber
materials.
Based on the standpoint above, a short account of some proposals is given in the next
chapter.
2. Outline of durable, hydrophilic SR agent

4. 4
Figure 1 Example of durable, water absorbent SR agent structure
Some proposals are indicated in Figure 1. First of all, for the skeletal, principal chain
structure of polymer, a selection should be made from the vinyl group, water-absorbent
silicone, isocyanate (urethane), polyester polymer, polyamide, fluorocarbon polymer and the
epoxy group in order to attain hydrophilicity to the fullest extent possible. The structure
then is bound, combined, or reacts with another hydrophilic group, for which the
incorporation of a cross-linking group or a hydrophilic moisture-retentive component will
work effectively.

5. 5
In general, as hydrophilic groups there are ethylene glycol, diethylene glycol, triethylene
glycol, alkylene oxide polymer, PEG, PPG, PEG block polymer, polyether, glycerin, sorbitol
etc.
For uses also as a cross-link, both end-terminal groups of chemical compounds should take
the form of the vinyl, glycidyl or allyl groups before application.
Squalane, chitosan, hyaluronic acid, collagen, sericin, natural protein, cellulosic substances
and thickeners are regularly used as moisture-retentive components.
Hydrophilic vinyl-polymer in Figure 1 Various devices will be possible based on
Figure 2-1, which shows an example of incorporating an acrylic acid copolymer to
each hydrophilic group. Durability will be added and stains can be removed easily.
Chemicals listed have been long used as bases for practising anti-staining techniques.
Water-absorbent silicone which carries reactive groups already possesses in its
structure cross-linking and hydrophilic properties and is also capable of producing
soft hand. Since it can cross-link with other hydrophilic groups, it is highly valued for
use in a durable, water-absorbent finishing agent or as an SR agent (see Figure 1 and
Figure 2-2).

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7. 7
By incorporating an etherizing compound, a polyether, alkoxylating compound to
diisocyanate, polyurethane with high hydrophilic properties can be obtained. It is a
very interesting cross-linking polymer which allows the formation of a highly durable
polymer by cross-linkage between hydrophilic groups and polyurethane, binding of
fluorine alcohol, as shown in Figure 2-3, or copolymerizing of hydrophilic vinyl
groups.
Since a hydrophilic polyester resin polymer skeleton is one that displays highest
affinity to polyester, it is used as a base in a wash-fast & water-absorbent SR agent for
polyester in the form of polymer such as PEG with improved hydrophilic properties.
Nowadays, it is often used as a high function compound, bound or mixed with
melamines, cationic silicones, block isocyanates, and hydrophilic group compounds
as shown in Figures 1 and 2-4.
As fluorine groups are fundamentally based on acryl or methacrylic acid type vinyl
groups, they are often copolymerized, as shown in Figures 1 and 2-5, with:
o diisocyanates (urethane adducts)
o hydrophilic groups (PEG with cross-linking group)
o acrylates, vinyliden chlorides etc
or, their adhesive properties can be strengthened with fluorine alcohol, amide and PEG, or
cross-linking resin polymer, their use is highly valued as oil-release properties can be
attained from a hydrophilic group, and oil-repellency from a fluorine-group chain.
Polyamide polymer and epoxy polymer are convenient polymer groups that allow a wide
range of applications such as below.
Incorporation of a hydrophilic group using carboxylic acid
Use of an epoxy group as a cross-linking agent
Copolymerization with a functional polymer
Use as an interactive cross-linking
Although the above is an overview that would only scratch the surface, crucial basics have
been included. In the following chapters 3 and 4, a description of the products, developed
based on our long-accumulated research data, will be given with references to Figures 1 and
3. Quest-DCO
This is a wash-fast, water-absorbent, quick-dry, anti-stain SR agent/softener for polyester.
The addition of durable hydrophilicity to polyester and its blends will bring about durable
anti-static properties, facilitate removal of oil stains and therefore result in superior oil-
release properties.
This product, which also works as a softener other than giving SR properties, is an agent
capable of upgrading polyester with multiple functions. Having different uses and
application areas from water/oil-repellent SR finishing, it allows a considerably wider scope
of application as mentioned earlier.

8. 8
This is a hydrophilic polymer which displays strong adhesive properties to polyester, and
the performance of treated fabric will not deteriorate even after 10 launderings. In brief, it
imparts to PET, E/C and E/R fibers the following properties:
Durable water absorbency, quick-dry, SR, and easy oil-stain removing OR properties
during laundering
Hydrophilic and anti-static properties
Soft hand, smoothness and flexibility
High fastness to washing, with minimal deterioration due to home laundering
It forms a highly-durable film on the fiber surface by undergoing padding, drying
and curing treatments (150-180°C x 30sec.).
Oil stains could be heavy oil, motor oil, lubricant, grease, spice oils, butter,
mayonnaise, ketchup, vegetable oils, lipstick etc, all very hard to remove, however,
stains on fabric treated with Quest-DCO wash out easily by washing and the effect
(OR properties) will not deteriorate even after repeated washes.
Table 2 shows the characteristics, effects and physical properties (appearance, pH and
ionicity) of Quest-DCO with directions for use.

9. 9
Table2 Characteristics, performances, physical properties and directions for use
Quest-DCO Quest-CSR
Materials to which Polyester fiber, other blended cloths Cotton, cellulose, polyester fiber,
they are applied other all fibres
Use as Wash fast, water absorbent, quick Wash fast, laundering, dry cleaning,
drying, anti-stain. SR plus softener high absorbency, hydrophilic agent
Properties:
Hydrophilic, water absorbency, Wash-fast, DC fast, non-
quick dryness, SR plus softening yellowing, soft hand, highly water
/ perspiration absorbent and
hydrophilic
Effect: Durability, antistatic property
Durability, antistatic property
Anti-oil staining, anti soil re-
deposition, oil removing / oil Using resin plus finishing agent at
release property the same time leads to low water
repellency and higher water
absorbency
Sports wear, casual wear, shirting,
underwear, dress shirts etc
Smoothness
Characteristics This is a hydrophilic polymer which has This has a good compatibility with
a strong adhesive property towards all resin polymers, catalysts,
polyester fiber, and the cloth treated softeners, Si, all finishing agents and
with this will not have low water fluorescent dyes
absorbency even after 10-20 times
laundering
Composition Cross linking, hydrophilic polymer Highly molecular surfactant
dispersion
Appearance Colourless semiopaque paste Opaque white liquid
Ionic property Nonionic Nonionic, weak anionic
pH 5–6 6-7 Dissolves easily in water in
Solubility Disperse easily in water arbitrary proportions
Polyester fibre Cotton, rayon, PET, synthetic fiber
Quest-DCO : 1-3% Quest-CSR : 0.5 – 4%
Resin polymer Resin, catalyst, finishing
OK to use with other agents, silicone, softener,
finishing agents cationic activator
ο
ο Dry [100-120ºC Cure [180ºC x 30 sec]
ο Durability improvement
Cold bath

10. 10
It is an extremely convenient finishing agent which can easily be combined with other
chemicals without causing yellowing, color alteration, or any factors that will degrade
dyeing fastness. Figure 3 shows the water absorbency (150mm in 10 min.) and the oil-
removing properties of DCO-treated polyester tropical cloth, padded with 3% DCO solution
and then dried. The initial performance is maintained after 1, 5 and even 10 washes.
Note: Home laundry detergent: 1.5g/L
45°C x 5min
A cycle of cold rinsing -dehydration-drying counted as 1 wash
Water absorbency: 150mm (10min) at the beginning and 130mm (10min) after 10
washes
Durable OR properties indicated in the performance index of 90 after 10 washes, as
opposed to the initial 100
DCO’s performance is rated highly as both the water absorbency and oil release
properties remain poor in the untreated fabric.

11. 11
Figure 3 Performance of Quest- DCO treated cloth [wash-fast water absorbency, oil-
removal]
Quest-DCO treatment (3% Pad→
Dry) cloth (polyester tropical)
water absorbency (mm) and oil
removal properly at initial
laundering and after laundering
Washing the treated cloth again with
Oil stains on after 10 times laundering
Water absorbency
Oil removal property
150 mm
Oil removal property
Water absorbency
After 10 times laundering
After 5 times laundering
After 1 time laundering
Initial laundering
Untreated Quest-DCO

12. 12
In Picture 1, water absorbency is compared before and after 10 washes in vertical wicking
distances (cm/10 min.) of dye liquor absorption in fabric (polyester) padded with DCO 3%
solution, dried and cured (180°C x 30 sec).
From this, it is clear that the untreated cloth has practically no water absorbency, while the
treated fabric maintains significantly higher water absorbency even after 10 washes.
Picture 1 Comparison of water absorbency of Quest-treated cloth and untreated before
and after washing
PET
QUEST QUEST QUEST QUEST
-DCO -DCO -DCO -DCO
3% Sol. Pad→ 3% Sol. Pad→ 3% Sol. Pad→ 3% Sol. Pad→
ORIGINAL dry→Qure dry→Qure ORIGINAL dry→Qure dry→Qure
(180º x 30sec) (180º x 30sec) (180º x 30sec) (180º x 30sec)
After 0 Home Laundry After 10 times Laundry
QUEST-CSR:
This is a wash-fast water-absorbency improver which functions effectively with all kinds of
fiber material, including cotton, cellulose, synthetics (polyester, nylon, acryl etc), blends and
union cloths.
In combined use in the durable water-absorbent, anti-static finishing of synthetic fiber, or
with other chemicals and finishing auxiliaries (resins, cationic surfactants, softeners, silicone
softeners and fixing agents) which turn natural fiber water-repellent, Quest-CSR will be
effective in degrading water repellency, upgrading water absorbency and penetration.
Moreover, it is suitable for all treatments that require durable, high water/perspiration-
absorbent finishing.
Superior wash and dry cleaning fastness without color alteration, yellowing, or
deterioration in fastness
Superior compatibility with resins, catalysts, fluorescent brighteners and finishing
agents, with good in-bath stability
The addition of potent water absorbency results in improved oil repellency and easier
oil release (SR, OR).
Imparts soft hand

13. 13
Table 2 is an outline of the characteristics and physical properties of Quest-CSR with
directions for use.
In the evaluation of water absorbency, the following two points need to be considered:
• The speed of water absorption (sec)
• The amount of water absorbed within given time (water absorption)
The speed of water absorption is important and can be figured by measuring the time (sec) it
takes for a drop of water on a fabric surface to be absorbed completely.
Figure 4 compares speed of water absorption before and after 50°C x 30 min washing
(drying) of PET, cotton and E/C blend fabric, each padded with Quest-CSR, dried and
cured.
Figure4 Water absorption speed of Quest-CSR according to the type of fiber
0 Polyester cloth Cotton broad (with Rf) PET/C blended broad
absorbency cloth
140
Quest-CSR Quest-CSR Quest-CSR
1.5% sol. 3% sol. 3% sol,
Absorbency speed (sec)
Initial laundering
100 After laundering
(50ºC x 30 mins)
60
40
20
0
Untreated Quest-CSR C makers N makers Untreated Quest-CSR C makers N makers Untreated Quest-CSR C makers N makers
Even fabric with virtually no water absorbency in its original state absorbs water
instantaneously or within a few seconds after treatment with Quest-CSR. Some deterioration
due to washing can be recognized, however, superiority to our competitors' products is
significant as the absorption is instantaneous in cotton and takes around 50 seconds in
synthetics.

14. 14
The indication of "Rf-combined" for cotton broad in Figure 4 denotes combined use of the
resin finishing solution (10% glyoxal resin + 3% catalyst).
Figure 5 shows water absorbency measured in the vertical wicking distance (cm) of a given
period of time (10 min) from the bottom of the Quest-CSR treated cloth.
Figure5 Quest-CSR wash-fast water absorbency
Water absorbency
(height of dye liquid absorbed)
Cotton Polyester fiber
Water absorbency
After 5
Laundering
0 laundering
Untreated Rf Rf (10%) + Untreated Quest-CST
(Resin 10%) Quest-CSR
Pad →Dry→Cure (180ºC x 60s) Pad →Dry→Cure (180ºC x 60s)
Water absorbency deteriorates in cotton due to resin treatment (Rf: 10% glyoxal resin + 3%
catalyst, padding-drying-curing). However, the water absorbency improved considerably
with 3% CSR added in the resin finishing bath, and equally superior performance was
maintained even after 5 washes.
Similar effects can be expected in polyester, as shown in the result of treatment with 3% CSR
alone in Figure 5.
The extremely poor water absorbency in the untreated polyester was remarkably improved,
and without any deterioration after 5 washes