This study demonstrated that the variation in physical and chemical performance on cotton double jersey knit fabrics was decided by the knit structure, water repellent chemicals types and their concentration. Here, two types of double jersey fabrics were treated with different types of water repellent chemicals at different formulations to evaluate the performance of water repellent finishes on knit fabrics properties. The levels of water repellency of the fabrics were assessed by AATCC 127 hydrostatic head test method and by ISO 4920:2012 spray rating test method. To evaluate the performance of water repellent finishes on knit fabric properties, GSM, bursting strength test according to ASTM (D 3786-87) method, air permeability, color fastness to wash, water, perspiration, chlorinated water and color fastness to rubbing with ISO method were done. The results showed that both physical and chemical properties of the finished cotton knits, depend to a great extent on knit structure, the water repellent finish type and concentration to obtain water repellent fabrics with desirable properties.
Cotton is an outstanding versatile fibre with superior quality mainly comfort ability. Water repellency is one general functional property that is required for protective clothing without deteriorating the comfort ability. Water repellent textiles have many uses such as industrial, consumer and apparel purpose. This repellency can be achieved by applying water repellent chemicals which imparts a thin surface layer of chemicals on textile fibres by the modification of surface energy of textiles without much deterioration of other mechanical and aesthetic properties like strength, flexibility, lustre, breathability, softness etc. [
The first group of water repellent finishing agents is dispersion of fluorine compounds, namely fluorocarbon (FC). The final polymer, when applied to a fibre, should form a structure that presents a dense CF3 outer surface for maximum repellency. A typical structure is shown in below
The second group water repellent chemical is fluorocarbon resin with polymeric, hyperbranched dendrimers in a hydrocarbon. It is a novel FC development, is inspired by nature and therefore called bio-nic finishes. Fluorocarbon polymers are applied together with dendrimers. Dendrimers are highly branched oligomers with non-polar chains forming a starbrush structure (
Third group water repellent chemical structure is same as first one but fluorocarbon with isocyanate booster and the length of the perfluorinated side chains should be about 6 carbons. [
In the literature, some of researches on different water repellent chemicals, their application procedure, curing temperature, their durability and different wash fastness have been evaluated. [
In this experiment, 100% cotton double jersey knit fabrics (scoured and bleached) were used. At first fabric is finished with different types of water repellent chemicals by pad-dry-cure method. The fabrics were supplied by Essential Clothing Ltd, Bangladesh. Two types of double jersey fabrics were used here, one is rib (1 × 1) and another is interlock. Fabric specifications were given in
Supplied fabrics which presents good hydrophilic character were first finished by using three different fluorocarbon based water repellent chemicals in three different concentrations (70 g/L, 90 g/L and 100 g/L) to analyze the performance of different water repellent chemicals and their varying concentration on water repellency and other physical properties of the fabrics. In addition, fabrics were dyed by using following recipe which is given in
Dye application bath for double jersey fabrics
Name of Fabric | Type of Knit structure | GSM | Count | Composition |
---|---|---|---|---|
Double jersey | Rib (1 × 1) | 315 | 30 Ne | 100% cotton |
Interlock | 220 | 30 Ne | 100% cotton |
Dyes and chemicals | Rib fabric (Black color) | Shade | Interlock fabric (Red color) | Shade | ||
---|---|---|---|---|---|---|
Dyestuff | Reacto bond Black DN | 8% | Reactobond Red HW | 0.5% | ||
Auxiliaries | Jinlev ECO CL 225 (Levelling agent): 25 g/l Jintexy Ec SQ 117CA (Sequestering agent): 25 g/l Jingen Lub CBA (Wetting agent): 50 g/l | |||||
Basic Chemicals | Rib | Interlock | ||||
Glauber’s salt | 80 g/L | 16 g/L | ||||
Soda ash | 20 g/L | 9 g/L | ||||
Temperature 60˚C | ||||||
Time 90 min | ||||||
M:L 1:10 | ||||||
After treatment | Cold wash Acid wash 2 cc/L for 4 - 5 min (Green acid) Hot wash at 95˚C for 7 min Soap wash 2 g/L for 7 min (Soaping agent Jingen SP AW5045) Hot wash at 95˚C for 7 min (2 times) and then dry. | |||||
Three types of fluorocarbon based water repellent chemicals are used, first is fluorocarbon (FC) (trade name Nuva TTC, dispersion of fluorine compound, weakly cationic, Clariant), second is fluorocarbon with dendrimers (FC + D) (trade name Rucostar EEE6, fluorocarbon (C6) resin with polymeric, hyperbranched dendrimers in a hydrocarbon, weakly cationic, Rudolf chemie) and third is fluorocarbon with booster (FC + B) (trade name Lurotex protector RP ECO, C6 fluorocarbon finish with an unblocked isocyanate booster, weakly cationic, BASF).
Two types of double jersey derivative fabrics were treated with three different water repellent chemicals at three different conc. (70 g/L, 90 g/L and 100 g/L) from a separate bath with same bath condition. Fluorocarbon (FC), fluorocarbon with dendrimers (FC + D) and fluorocarbon with booster (FC + B) water repellent chemical’s solutions were prepared. The process parameters were adopted as recommended by the supplier and bath set up are given in
Finishing bath set up | FC | FC + D | FC + B | |
---|---|---|---|---|
Name of chemicals | Resin | 70, 90, 100 g/L of fluorocarbon resin | 70, 90, 100 g/L of fluorocarbon with dendrimers resin | 70, 90, 100 g/L of fluorocarbon with booster resin |
Acetic acid | 01 ml/L as required for pH 4 - 5 | 01 ml/L as required for pH 4 - 5 | 01 ml/L as Required for pH 4 - 5 | |
Perapret Booster XLR | -- | -- | 8% of the of fluorocarbon dosage | |
Application Parameters | Padding | 80% pick up | ||
Drying | 120˚C for 3 min | |||
Curing | 160˚C for 2 min | |||
Padder Pressure | 2.3 kg/cm2 |
for padding with 4.5 rpm fabric speed and 2.3 kg/cm2 padding pressure. Channel precision oven machine, made in China, was used for drying and Labtec Steamer machine (Newave Lab equipments Co Ltd, Taiwan) was used for curing.
1) Drop test: It checked the contact angle by using AATCC 79 method. ( one water droplet is placed on treated fabric from specific distance and checked the droplet visually to evaluate the water repellency. When water droplet is placed on finished fabric then the drop will rest up on it and will not penetrate it means that the finished material surface has lower surface tension than water surface tension, then that material is called water repellent.)
2) Spray rating test: The spray rating tests were evaluted by using ISO 4920:2012 test method.
3) Hydrostatic Head Test: It was done by Shirley hydrostatic head tester, England according to AATCC 127 method.
Each samples were tested in the standard atmosphere, 25˚C ± 2˚C temperature and 65% RH after conditioning 24 hrs.
1) GSM test: GSM test was done by GSM cutter from James H. Heal & Co. Ltd. Halifax, England according to ASTM (D 3776-79) method.
2) Bursting strength test: It was done by bursting strength tester from SDL Atlas according to ASTM (D 3786-87) method.
3) Air permeability test: It is done by using Textest FX 3300 Labair air permeability tester, Textest Instrument, Switzerland according to ISO 9237 method.
4) Color fastness to wash: Color fastness to wash was measured with ISO-105 C2S method.
5) Color fastness to water: It is done by ISO 105-E01 method.
6) Color fastness to chlorinated water: It is done by ISO 105-E03 method
7) Color fastness to perspiration: It is done by ISO 105-E04 method
8) Color fastness to rubbing: The resistance of color against rubbing of dyed fabrics (dry and wet) were evaluated with ISO-105-X 12 method.
Three fluorocarbon based water repellent solutions (trade name Nuva TTC, Rcostar EEE6 and Lurotex protector RP ECO) were prepared in 70 g/L, 90 g/L and 100 g/L conc. and applied these conc. on different 100% cotton double jersey knit fabrics. Two different double jersey knit fabrics were used in here which were 1 × 1 rib and interlock.
This is the visual test to evaluate the water repellency. If the material surface has lower surface tension than water surface tension, then that material is called water repellent. When water drop is placed on water repellent material then the drop will rest up on it and will not penetrate, then it will be called water repellent.
Here are some physical appearances of untreated and treated rib and interlock fabrics by using fluorocarbon with dendrimer chemicals (trade name is Rcostar EEE6 and expressed by FC + D) (
FC, FC + D and FC + B water repellent chemical’s solutions were prepared in 70 g/L, 90 g/L and 100 g/L conc. and applied on double jersey knit dyed fabrics. These treated fabrics were evaluated using ISO 4920:2012 method. The evaluated rating of the samples are given in chart with its graphical analysis. Schindler et al described that after completing the pad-dry-cure process, perfluoro side chains changed to almost crystalline structures by curing process to achieve optimal water repellency [
It is shown from
The hydrostatic head test was done according to AATCC 127 method on double jersey fabrics after water repellent finish at various conc. which are stated below in
Double jersey fabrics | Conc. (g/L) | FC | FC + D | FC + B |
---|---|---|---|---|
Rib | 70 | 3.5 | 4.5 | 4 |
Interlock | 3.5 | 4 | 3.5 | |
Rib | 90 | 4.5 | 4.5 | 4.5 |
Interlock | 4 | 4 | 4 | |
Rib | 100 | 4.5 | 4.5 | 4.5 |
Interlock | 4.5 | 4.5 | 4 |
From the above chart it has clearly seen that the more pressure is required to force water through the fabric. After gradually increasing the conc. from 70 g/L to 100 g/L, the pressure requires more. Rib fabric has higher hydrostatic head test rating than interlock fabric because of rib fabric has higher GSM and more compactness. An increase in repellent conc. caused an increase in wetting times of the fabric after finishing. In all conc., FC + D water repellent chemical shows better hydrostatic head test rating than FC + B and FC water repellent chemicals for both rib and double jersey fabrics. Because the water repellent chemicals form a coating on the fabric and the more conc. of chemicals leads the higher density of the coating resulting increased water repellency.
The GSM tests were done according to ASTM (D 3776-79) method for fabrics with different conc. The chart has given below:
After chemical implementation of different double jersey knit fabrics with different water repellents at various conc. are stated above
Bursting strength plays a significant role after water repllent finish. It was done according to ASTM (D 3786-87) method. From the
Double jersey fabrics | Conc. (g/L) | GSM (before) | FC | FC + D | FC + B |
---|---|---|---|---|---|
Rib | 70 | 315 | 325 | 323 | 322 |
Interlock | 220 | 230 | 229 | 227 | |
Rib | 90 | 315 | 328 | 327 | 326 |
Interlock | 220 | 237 | 238 | 239 | |
Rib | 100 | 315 | 330 | 332 | 334 |
Interlock | 220 | 240 | 243 | 241 |
Double jersey fabrics | Conc. (g/L) | Bursting Strength (kpa) (before) | FC | FC + D | FC + B |
---|---|---|---|---|---|
Rib | 70 | 438.1 | 402.0 | 403.7 | 406.3 |
Interlock | 328.3 | 294.2 | 300.5 | 290.7 | |
Rib | 90 | 438.1 | 400.5 | 397.8 | 398.3 |
Interlock | 328.3 | 280.3 | 284.9 | 285.5 | |
Rib | 100 | 438.1 | 393.4 | 380.7 | 391.2 |
Interlock | 328.3 | 281.1 | 285.4 | 293.3 |
The fabric’s strength is decreased by increasing of concentration. When the water repellent chemicals form cross link with the cotton free O-H group in the amorphous region, it makes stiff of the fabric and moreover, cross linking reaction is done mainly in acidic condition which are also responsible for the reduction of the bursting strength.
It was done by using ISO 9237 method. The air permeability of double jersey fabrics decreased via water repellent finish which are stated in
Double jersey fabrics | Conc. (g/L) | Air permeability (cm3/cm2/s) (before) | FC | FC + D | FC + B |
---|---|---|---|---|---|
Rib | 70 | 83.3 | 51.0 | 67.4 | 78.1 |
Interlock | 62.0 | 45.3 | 46.9 | 48.2 | |
Rib | 90 | 83.3 | 55.8 | 65.9 | 77.1 |
Interlock | 62.0 | 39.7 | 40.7 | 44.5 | |
Rib | 100 | 83.3 | 51.2 | 62.5 | 75.6 |
Interlock | 62.0 | 35.9 | 36.2 | 39.0 |
The wash fastness of water repellent treated fabric with 100 g/L conc. is rated under grey scale for two types of measurement, one is for color change and another is for color staining. Color fastness to wash was measured with ISO-105/C06-C2S method.
The wash fastness of all water repellent chemicals are measured at 100 g/L conc. as it showed the best water repellency and physical properties compared with other concentrations. From
To investigate the effect of water fastness of water repellent treated fabrics are rated under grey scale for two types of measurement, one is for color change and another is for color staining. It is done by ISO 105-E01 method. The rated chart is given below in
The water fastness of FC and FC + B water repellent chemicals reduced than untreated one though FC + D chemicals remained unchanged for rib fabric. Water fastness remained unchanged for FC, FC + D and FC + B chemicals for interlock fabric. The improvement of wash fastness of water repellent finish is because of the dye molecules trapped inside the crosslinking film.
To evaluate the effect of chlorinated water fastness of treated fabrics are rated under grey scale for color change. The rated chart is given below in
The resistance of color against acid and alkali of dyed fabrics are done by ISO 105-E04 method. The rated chart is given below in
The rubbing fastness of water repellent treated dyed fabrics are rated under grey scale for the measurement of color staining against dry and wet white fabric. The rated chart of rubbing fastness for wet and dry rub are given below in
In this study, the effect of water repellent finishes on double jersey structured knit fabrics and water repellent chemicals conc. on the water repellency of the fabrics were investigated. To do so, 36 repellent treated different structured knit fabrics samples were tested and obtained results were evaluated. Different physical and chemical test results showed that the repellent types and their conc. ranges significantly influenced water repellency of double jersey knit fabrics. For water repellent finishing, the variation in the water repellency performance and comfort properties of treated cotton fabrics is mainly depends on their structure and chemical’s add on. When fluorocarbon with dendrimers (FC + D) was used, then the best water repellency is obtained. Changing conc. from lower to higher
Color fastness to wash | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Fabric | Unfinished | FC | FC + D | FC + B | ||||||||
Color change | Color staining | Color change | Color staining | Color change | Color staining | Color change | Color staining | |||||
Cotton | Wool | Cotton | Wool | Cotton | Wool | Cotton | Wool | |||||
Rib | 4 | 3 | 4 | 4 | 3 - 4 | 4 | 4 | 3 - 4 | 4 | 4 | 4 | 4 |
Interlock | 4 | 3 - 4 | 4 | 3 - 4 | 3 - 4 | 4 | 3 - 4 | 3 - 4 | 4 | 3 - 4 | 3 - 4 | 4 |
Color fastness to water | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Sample | Unfinished | FC | FC + D | FC + B | ||||||||
Color change | Color staining | Color change | Color staining | Color change | Color staining | Color change | Color staining | |||||
Cotton | Wool | Cotton | Wool | Cotton | Wool | Cotton | Wool | |||||
Rib | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 | 4 - 5 |
Interlock | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 |
Color fastness to chlorinated water | ||||
---|---|---|---|---|
Sample | Unfinished | FC | FC + D | FC + B |
Color change | Color change | Color change | Color change | |
Rib | 4 | 3 - 4 | 4 | 3 - 4 |
Interlock | 4 | 3 - 4 | 3 - 4 | 3 - 4 |
Color fastness to perspiration | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Sample | Unfinished | FC | FC + D | FC + B | ||||||||
Color change | Color staining | Color change | Color staining | Color change | Color staining | Color change | Color staining | |||||
Acid | Alkali | Acid | Alkali | Acid | Alkali | Acid | Alkali | |||||
Rib | 4 | 3 - 4 | 4 | 4 - 5 | 4 | 4 - 5 | 4 - 5 | 4 | 4 - 5 | 4 - 5 | 4 | 4 - 5 |
Interlock | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 | 4 - 5 |
Rubbing fastness | ||||||||
---|---|---|---|---|---|---|---|---|
Sample | Unfinished | FC | FC + D | FC + B | ||||
Dry | Wet | Dry | Wet | Dry | Wet | Dry | Wet | |
Rib | 4 - 5 | 3 | 4 | 3 - 4 | 4 | 3 | 4 | 3 |
Interlock | 4 - 5 | 4 | 4 - 5 | 4 | 4 - 5 | 4 | 4 - 5 | 4 |
concentrations, gives gradually increased water repellency, regardless of repellent chemical type. From hydrostatic head test, it has clearly seen that the more pressure is required to force water through the fabric after finishing and gradually increasing the conc. from 70 g/L to 100g/L, the pressure requires more. Rib fabric has higher hydrostatic head test rating than interlock fabric because of rib fabric has higher GSM and more compactness. However, unlike the findings of previous research works which described that if the water repellent was used with higher conc., strength is decreased. The repellent chemicals and their changing conc. did not cause significant change to bursting strength of knit fabrics. There was no remarkable deviation is observed in GSM on the basis of water repellent chemicals and their varying conc. Moreover, fabric’s GSM rises due to the mechanical reinforcement by formation of bonds within interfibre and interyarn. It is attributed in decrease of bursting strength and air permeability because of a direct consequence of deposition of a thin film onto or within the fibre. Air permeability of fabric is decreased after water repellent finish because of the restriction effect to the airflow. Air permeability rating of FC + B for both rib and interlock fabrics gave comparatively better result than FC and FC + D water repellent chemicals. A higher in repellent chemical conc. caused a higher wash fastness, water fastness, color fastness to perspiration and rubbing fastness. However, a higher in repellent chemical conc. caused a minor effect on color fastness to chlorinated water. Fabric finishing after dyeing, had no effect on water repellency is another important conclusion of this work.
I should like to express my deep gratitude to MICRO FIBRE for providing me the lab facilities. I should also like to thank Essential Clothing Ltd for providing me sample fabrics. Again special gratitude also goes to the Wet Processing Lab and the TTQC Lab of Bangladesh University of Textiles (Butex).
Chowdhury, K.P. (2018) Impact of Different Water Repellent Finishes on Cotton Double Jersey Fabrics. Journal of Textile Science and Technology, 4, 85-99. https://doi.org/10.4236/jtst.2018.43006