Fabric Drying Rate Test

In recent years, rising living standards have increased interest in moisture-wicking, quick-drying clothes. People now recognize their ability to absorb moisture, breathe, and wick sweat. In sports, it’s common. Many global brands use moisture-wicking, quick-drying fabrics in their clothing. Due to social and economic growth, there is a higher demand for functional fabrics. Research on moisture-absorbent and quick-drying fabrics is ongoing. Researchers from the General Logistics Institute of Military Equipment proposed an index. It tests fabrics’ performance in heat and moisture transfer when humans sweat. It helps to evaluate fabrics’ performance. Chen Yaping et al. I chose two kinds of fibres. I analysed three factors using orthogonal experiments. Then, I used grey approximation of the optimal evaluation method. This found the fabric with the best overall performance. French scholars developed new dental work clothes. In a lab, an infrared camera recorded the splash area of saliva, water, and debris. They used this to select the shape of different functional fabrics. The fabric evaluation indexes and performance tests are key to clothing design. They measure the fabric’s functionality.

What is fabric drying rate?

The drying rate of fabrics is the time needed for fabrics to dry completely from wetness. Let’s say you wash your clothes, hang them out to dry and then wonder how long it takes for them to dry completely. That time is the drying rate! The drying rate of fabrics measures how quickly they absorb moisture. It is important for keeping the wearer dry and comfortable. A fabric’s drying rate depends on several factors. These include its material, thickness, and weave. Also, the ambient humidity and temperature matter. High-drying fabrics usually absorb moisture well and dry quickly.

What are high drying rate fabrics?

Fabrics with a high drying rate absorb and expel sweat quickly. These fabrics are usually very breathable and moisture-wicking. They allow sweat to evaporate quickly, keeping the body dry and comfortable. The following summarises common high drying rate fabric fabrics.

Polyester: It quickly absorbs sweat from the skin. Then, it evaporates.

Nylon： has good breathability and moisture-wicking. It’s suitable for sportswear and outdoor clothing.

Polyester: It’s used to make quick-drying clothes and sportswear. It wicks moisture and dries fast.

Polyester/Cotton: These blended fabrics combine polyester and cotton. They have the comfort of cotton and the quick-drying properties of polyester. So, they are a common, high drying rate fabric.

Spandex: Often added to athletic fabrics to improve stretch and comfort in clothing. Spandex does not wick moisture well. But, it helps the fabric fit better against the skin. This speeds up sweat evaporation.

Ice silk: A special fabric for sportswear. It has a unique fibre structure and process. It wicks moisture and dries quickly.

Drying rate test standard

The AATCC has approved two new test standards. They evaluate fabric drying rates. You can use the following standards and methods to analyze the dryness of fabrics:

AATCC Test Method 200-2013, Drying Rate of Textiles in the Absorbent Range: Airflow Method

AATCC Test Method 201-2013, Fabric Drying Rate: Hot Plate Method

These tests simulate real wear. They expose the fabric to air and skin contact.

Test Purpose and Scope

The AATCC 201 Heated Plate Method is a commonly used method for fabric drying rate testing. The contact heating plate is set at 37°C, the same as the human body. This simulates perspiration on the skin. The method works on many fabrics, including knitted, woven, and non-woven ones. This test method is more traditional. It needs more equipment and has a complex procedure. Later, we will introduce today’s advanced fabric drying rate testers.

Test Principle

A fabric’s drying rate is the rate of evaporation. It is in contact with a defined amount of water at the interface of a heated metal plate at a constant temperature.

For the test samples, 10 types of moisture wicking and quick drying fabrics, 1 type of cool feeling fabric, 1 type of moisture wicking fabric and 3 types of normal fabrics were used for comparison.

Sample Preparation

We cut three specimens, each measuring (15.0±0.5) cm x (15.0±0.5) cm, from the right, center, and left sides of the sample.

For a garment or finished product test, we cut samples from different parts, like the sleeves and front.

If the test samples are hosiery, detach their parts along the length. Then, test them separately. If the sample is too small for the test, water migration must be closely monitored. If the water solution moves to the edges of the sample, it reduces the water volume. The test is then repeated with a new sample.

Before testing, we conduct moisture equilibration according to ASTM D1776. It is the standard for moisture equilibration and testing of textiles. The samples are each put on a screen or perforated partition in a humidifying rack. They are then equilibrated for at least 4 hours at 21°C±2°C (70°F±4) and 65%±5% relative humidity in a standard atmosphere.

Conduct all dry rate tests under standard conditions.

Test Methods

We conducted tests according to national standards. They were: drip diffusion area, moisture permeability, water absorption, core absorption height, evaporation, and air permeability. We left all samples to stand in the standard environment for 24 hours. The test conditions were: temperature ( 25 ± 2) °C, humidity 65.0% ± 5.0%, wind speed 1.00 m/s. These methods analyzed the test results based on (1) the fabrics’ temperature, (2) their humidity, and (3) the wind speed.

Data analysis

1. Drip diffusion area analysis

The drip diffusion area of the 15 fabrics changed little after washing. The ratio of the front and back surfaces’ drip diffusion areas did not change much, either. So, washing had no obvious effect on the fabrics’ drip diffusion areas. Fig shows. Moisture-absorbent, quick-drying fabrics are better than ordinary ones. Their drip diffusion area is larger. The front and back surfaces of the former have a big change, reaching 69 mm². In contrast, the drip diffusion area of the ordinary fabrics 7*, 11*, and 13* is almost zero. Thus, these fabrics failed to absorb moisture quickly in a 3-second test. Washing does not affect this fabric’s moisture absorption. It has no noticeable effect on its moisture absorption. In other words, these fabrics are slow to absorb water within 3 s of the dry rate test. This affects their moisture absorption and quick-drying properties. The 10# moisture-wicking, copper-ammonia knit fabric has a drip diffusion area of almost 0. This means its moisture absorption is not ideal.

2. Moisture permeability analysis

The 14# fabric had the highest moisture permeability before washing. It decreased after washing. For the 2# and 13# fabrics, it increased significantly after washing, both before and after. Most fabrics showed little change in moisture permeability after washing. The 15# fabric showed almost no change. There is no clear advantage of moisture-absorbent, quick-drying fabrics over ordinary ones.

3. Water absorption analysis

The 15 fabrics’ water absorbency did not change much after washing. But, all showed a slight increase in absorbency. Knitted fabrics absorb moisture better than woven ones. This is mainly because knitted yarns are usually less twisted. Also, the loop structure of knits creates more porosity. Thus, they have a higher water absorption rate. Knitted fabrics made of COOLMAX, COOLAIR, and other quick-drying, moisture-absorbing fibres or polypropylene have high water absorption. This shows that using these functional fibres is effective.

4. Core absorption height analysis

The core absorption height values of ordinary fabrics 7*, 11*, and 13* are very small. This means their core absorption performance is poor. It affects their moisture absorption and quick-drying properties. The 10 quick-drying, moisture-absorbing fabrics have high core absorption. Their maximum height is 284 mm. They meet the required functions. The 8# cool feeling fabric and 10# copper-ammonia knit fabric have low core absorption heights. So, their functionality is not obvious. Comparing with Fig. 4( a) ( b) shows that, after washing, 15 fabrics had the same core absorption. Except for 7* and 10# copper-ammonia knitted fabric, the warp direction absorbed better than the weft.

5. Evaporation analysis

The moisture and evaporation rates of ordinary fabrics 7*, 11*, 13* are low. This shows that they are not very quick-drying. Ten kinds of quick-drying, moisture-absorbent fabrics have a high evaporation rate. Of these, 6# fabrics have the highest rate. Their thinness and light weight help water evaporate. 7*, 6#, 11* fabrics contain cotton or copper-ammonia. The other fabrics are superior in the warp direction. Cellulose fibre, made of cotton or copper-ammonia, is hygroscopic. The fabric absorbs its moisture and it does not evaporate quickly. So, the water evaporation and evaporation rates are low.

6. Air permeability analysis

Knitted fabrics are more permeable to air than woven ones. This is due to their higher porosity and lower yarn twist. Also, knitted fabrics with less thickness and mass are more permeable to air.

Comprehensive Evaluation

Testing a fabric’s properties can show its performance in a specific area. In practice, we must consider many factors to evaluate a fabric’s performance. This paper uses a fuzzy comprehensive evaluation method to assess 15 fabrics. It ranks their moisture-absorbing and quick-drying abilities. Apparel designers can use this as a reference.

（1）Moisture-absorbing, quick-drying fabrics perform much better than ordinary ones. This explains their current popularity in the market.

（2）Loop-knit fabrics are better than weft flat knits. They absorb moisture and dry quickly. In woven fabrics, twill weaves are slightly better than plain weaves at these tasks. Twill fabrics can improve their performance with moisture-absorbing and perspiring finishes. Fabrics made of moisture-absorbing and perspiring yarns have the best overall performance.

（3） Fibres like COOLMAX, polypropylene, and COOLAIR are moisture-absorbent and quick-drying. They perform better than common fibres like polyester, polyamide, and spandex.

（4） Finishing fabrics perform better than those made of moisture-absorbing, quick-drying fibres. But, their performance after washing is not stable.

（5）9#, 14#, 15# are 100% polyester, twill, woven fabric.

Conclusion

Square metre quality ranking: 14# > 9# > 15#.

Moisture absorption and quick drying performance: 14# > 9# > 15#.

The 14# fabric has a moisture-wicking finish. Moisture-wicking yarns make the 9# and 15# fabrics.

In conclusion, manufacturers can finish normal fabrics to make them moisture-wicking. The fabric’s quality and raw materials are key to its moisture-wicking abilities. The analysis shows that 3# and 9# are best for making moisture-absorbing, quick-drying clothes. 10# fabrics absorb less moisture and dry slowly. But, they have copper-ammonia filament, which gives a cool feel. So, you can use them for trendy clothing. 11# is a normal fabric. It has poor moisture-absorbing and quick-drying ability. So, it is not suitable for functional apparel.

The lab tested 15 fabric types on various moisture-related factors. It then ranked them using a fuzzy judgement method with a mean square deviation for weight. The analysis shows that moisture-absorbing, quick-drying fabrics are much better than ordinary ones. Among them, 2# and 3# are the best at moisture absorption and quick-drying in knitted fabrics. 11# is the worst. In woven fabrics, 14# and 9# are the best at moisture absorption and quick-drying. 9# has more stable performance than 12#, which is the worst.

Definition of water absorption

After fully wetting the specimen in the water, it dripped. It then absorbed water equal to a percentage of its original mass.

Water absorption rate evaluation index

Water absorption is the main test of a textile’s moisture. It should be achieved before and after washing.

Water absorption rate of knitted products (%): ≥200

Knitted products water absorption (%): ≥100

Definition of drip diffusion time

The time for drops of water on the specimen to diffuse and penetrate the fabric after contact.

Drip diffusion time test method

1. Cut 5 flat, wrinkle-free, representative specimens. Each must be at least 10cm x 10cm.

2. Place the specimen in the standard atmospheric conditions to adjust the moisture balance;

3. Place the specimen on the test platform (skin side up). Inhale an appropriate amount of tertiary water with a buret. Then, gently drop about 0.2 mL of water on the specimen. The mouth of the buret should be no more than 1 cm from the specimen’s surface.

4. Carefully observe the diffusion of water droplets. Record the time, to 0.1s, for the droplets to contact the specimen’s surface and fully diffuse (no longer reflect). If the droplets diffuse slowly and are not fully diffused after 300s, stop the dry rate test. Record the time as > 300s.

5. Calculate the drip diffusion time of each specimen. Then, report the average value. We trim the result to 0.1s.

Drip diffusion time evaluation index

Drip diffusion time is a key test of a textile’s moisture absorption. It should be the same before and after washing.

Knitted products drip diffusion time (s): ≤ 3

Drip diffusion time of knitted products (s): ≤ 5

Definition of core absorption height

The dry rate test measures the capillary effect of the material. It does this by wetting one end of a vertically suspended textile. The water should rise along the textile within a set time due to capillary action.

Core suction height test method

1. Cut representative specimens. Warp (or longitudinal) 3, weft (or transverse) 3. Each specimen must be 250mm × 30mm. This ensures the side yarn is complete along the length of the specimen.

2. Place the specimens in standard atmospheric conditions to adjust the moisture balance;

3. Fix one end of each of the 6 specimens to the beam frame of the instrument. Then, install tension clamps at the lower end of the specimens. Set them to 8mm~10mm to keep the specimens vertical.

4. Adjust the specimen. It should be close to and parallel to the scale. The lower end of the specimen must be 15mm±2mm below the zero position of the scale.

5. Lower the beam frame until the liquid in the scale’s zero position is 15mm below the 2mm mark. Then, start the timer.

6. Measure 30min when the liquid core suction height of the minimum value, in millimetres (mm);

7. were calculated in the longitudinal (or longitudinal), latitudinal (or transverse) each of the three specimens of the minimum value of the liquid core suction height of the average value, the results are retained to one decimal point.

Assessment index of core absorption height

Core absorption height is the main test of a textile’s moisture absorption. It should be the same before and after washing.

Knitted products core absorption height (mm): ≥100

Knitted products core absorption height (mm): ≥90

Evaporation rate and evaporation time definition

Evaporation rate: A certain amount of water drops on the specimen. After natural evaporation in the standard atmosphere, its time-evaporation curve is linear for a given mass lost per unit time.

Evaporation time: the time it takes for all water to evaporate from a specimen after hanging in the standard atmosphere.

Evaporation rate test method

1. Cut a 5-piece specimen, each at least 10cm × 10cm. It must be flat and wrinkle-free.

2. Place the specimen in the standard atmospheric conditions to adjust the moisture balance;

3. Weigh the original mass of the specimen, accurate to 0.001g;

4. Place the specimen on the test platform (skin side up). Inhale an appropriate amount of tertiary water with a burette. Then, gently drop about 0.2ml of water on the specimen. The burette’s mouth should be no more than 1cm from the specimen’s surface.

5. Weigh the specimen, which drips with water. Then, suspend it in the standard atmosphere. Hang it vertically, letting it spread naturally.

6. Weigh the mass, accurate to 0.001g, every 5 ± 0.5min. End the test when two consecutive weighings show a change of less than 1%. If the specimen evaporates quickly, shorten the weighing interval to 3min or 1min.

7. Calculate the evaporation rate of each specimen and take the average value reported.

Evaporation rate evaluation index

Evaporation rate is a key measure of textile dryness. It should be the same before and after washing.

Knitted, woven products evaporation rate of the same indicators, evaporation rate (g / h): ≥ 0.18

Principle of moisture permeability test

Put the moisture permeability cup, with desiccant, in a sealed, humid environment at a specified temperature. A fabric specimen seals it. Then, calculate the moisture permeability rate of the specimen. Do this by measuring the change in the cup’s mass over a set period.

Moisture permeability test method

1. Cut a representative specimen of 3 pieces, each 70mm in diameter. The specimen must be flat and uniform. There must be no holes, pinholes, wrinkles, scratches, or other defects.

2. Adjust the specimen in the standard atmospheric conditions of moisture balance.

3. Load about 35g of desiccant into the clean, dry, moisture-permeable cup. Then, oscillate it to make the desiccant level.

4. The specimen test side up, in the moisture permeability cup. Load it with gaskets and the pressure ring. Screw on the nut. Then, use vinyl tape to seal the pressure ring, gaskets, and cup. This is the test assembly.

5. Quickly place the test combination in the test chamber under the specified test conditions. Remove it after 1 hour of equilibrium.

6. Quickly cover the corresponding cup with a lid. Place it in a 20 ℃ silica gel desiccator for 30 min. Weigh it one by one, accurate to 0.001g. Each test’s weighing time must not exceed 15s.

7. After weighing, slightly vibrate the desiccant in the cup to mix it. Avoid contact with the test specimen.

8. Remove the cup cover. Quickly put the test combination into the test box. After 1 hour, remove the test. Then, weigh it. Each weighing of the test combination should be consistent.

9. Researchers used two weighings to calculate the moisture permeability of three specimens. The average value was then revised to three significant figures.

Moisture permeability evaluation index

Moisture permeability is a key test for a textile’s quick drying. You should meet before and after washing.

Moisture permeability of knitted products [g/(m2-d)]: ≥10000

Moisture permeability of knitted products [g/(m2-d)]: ≥8000

Comparison of test procedures

A comparison of the AATCC 201 standard and SmartDry found that the AATCC 201 test steps are old and complicated. They require manual calculation of the results. In contrast, SmartDry is easy to use and has a smart calculation function. This reduces manual errors.

AATCC 201 Standard Test Procedure

Turn on the thermostat and airbox of the removable heater to maintain the temperature of the metal plate at 37°C ± 1°C (99°F ± 2°F).

Use a hot-wire anemometer to ensure that the air velocity through the plate is 1.5 m/s ± 0.5 m/s. Measure the airflow directly after the infrared thermocouple probe.

The metal plate preheated the specimen for 5 min. This made its temperature equal to that of the heating plate. The sample’s edge was near the metal plate’s outer skin. A magnetic strip fixed the upper edge of the sample, near the bellows, to the plate.

Place the infrared thermocouple probe in the middle of the specimen, 1.0 cm ± 0.1 cm above the specimen. Mark the center of the metal plate. This will help observe the infrared thermocouple probe.

Switch on the recorder. Lift the free end of the specimen (the side opposite the magnetic strip). Then, place 0.200mL ± 0.003mL of water on the infrared thermocouple probe and the metal plate below the specimen. Lower the specimen to cover the water droplet. The instant the specimen comes into contact with the water is the start time.

Observe the specimen to determine the capillary effect caused by the water. Do not let water penetrate the edges of the specimen due to capillary action. If it does, use a larger specimen or use less water.

Collect and record the temperature every second. Stop when it returns to the initial value. Repeat for other specimens.

Test Procedure

Open the water tank lid at the rear of the unit and ensure that there is sufficient water in the tank.

Connect the power cord to the power supply socket. Then, switch on the power supply and the equipment. After switching on, the equipment will preheat automatically.

Open the operation cover. Lay the sample flat in the test area, with the right side of the magnetic tape pressed tightly. Then, gently close the operation cover. If you place the sample’s sides and the pattern differently, the test results will differ. So, pay special attention to this.)

Click ‘Mode’ in the main interface to open ‘Test Setting’. Change the data as per the test requirements. It includes the water dispensing mode, volume, unit, and equilibrium time. Also, it includes the hot plate temperature and wind speed. The device will automatically dispense liquid according to the set values.

The device will automatically dispense liquid based on the set values. It will also select the number of samples to test at once to complete the dry rate tests.

Click ‘Run’ to start the test. The device simulates human sweating to test how fast textiles dry. It will show a real-time view of the data. It will include wind speed, hot plate temperature, and infrared temperature. The device will also record the hot plate temperature data and retain all test data.

Click the Finish button after testing all samples of the same type.

After completing the test, click to enter the report list page to view the test results.

Fabric Drying Rate Result Judgement

To judge whether the drying rate of the fabric is good, you can refer to the following points:

Ideal quick-drying fabrics should dry quickly from a wet state. If the fabric takes a long time to dry, then its drying rate may not be high enough.

Tests to measure quick-drying properties are usually done at a constant temperature. If a fabric dries much faster than others at the same temperature, its drying rate is good.

Light and Breathable: Light and breathable fabrics tend to have better drying rates. This is because these fabrics, when wet, dry more easily by evaporation of moisture from the air.

These are general criteria for evaluating drying rates. Results may vary due to factors like material, fabric, and equipment. The higher the drying rate, the more likely the fabric is to dry. In general, the higher the drying rate, the better the quick-drying performance of the fabric.

Test equipment

The SmartDry Drying Rate Tester, per AATCC 201, has high-precision temp and wind speed sensors. It also has precision dripping devices. It can quickly simulate human sweating and determine the drying rate of textiles. The parallel cross-flow fan makes the wind speed more uniform. It restores the actual evaporation process and makes test results more reliable. Moreover, SmartDry is a smart device. It can connect via WIFI to the SmarTexLab app on phones. This allows remote setup of parameters to monitor the testing process. It greatly improves work efficiency.

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