Introduction Fabric pilling, which happens from wear and friction, is a common issue affecting fabric…
Table of Contents
1. Background of the birth of the MMT tester
As the textile industry enters the new century, textiles with liquid moisture management properties are becoming a popular industry with multi-million dollar sales. Since the late 1990s, led by the U.S. company Under Armour (note: the company is based in Baltimore and produces sports equipment), many companies began to promote products that “make the wearer feel more comfortable” and use this as a selling point to attract customers.
At that time, however, it was difficult to compare the performance of liquid moisture management between different products. This problem was not solved until the introduction of the Liquid Moisture Management Tester (MMT for short) in 2004. Prior to that, moisture testing was limited to a gross efficiency test or a droplet test, which tests a fabric’s ability to transfer liquids. To test, the fabric was placed vertically in a sink, or water was dripped on the fabric, and then the degree of water immersion into the fabric was tested. The shortcoming of these test methods is that they can only measure the one-way passage of water droplets on one side of the fabric. With the creation of the MMT tester, however, the liquid moisture management test can normally be completed in less than two minutes, and the following 10 indices can be measured and calculated for each test(MMT test).
● Wetting time of surface/substrate layer
● Water absorption speed of surface/substrate layer
● Maximum wetting radius of surface/substrate layer
● Liquid moisture diffusion rate of surface/substrate layer
● Cumulative unidirectional transfer capacity
● Overall liquid moisture management capacity
Obviously, MMT Tester can help textile companies to judge the comfort level of fabrics in a more scientific and comprehensive way. Of course, different moisture-checking machine manufacturers’ MMT testers may achieve different test indexes, so be sure to ask the manufacturer what indexes can be tested by the MMT Tester they produce before purchasing.
2. What is a Moisture Management Tester?
The Moisture Management Tester (MMT) tests the absorption and diffusion of perspiration in fabrics. A totally new kind of moisture testing. The absorption and diffusion of perspiration in fabrics directly affect the wearing comfort of garments. To improve the comfort of garments (especially sportswear fabrics), it is important to test the liquid moisture management capabilities of fabrics to help evaluate the moisture absorption and dryness performance of textiles and to improve material properties.
The liquid moisture management tester measures the overall dynamic performance of liquids in knitted and woven fabrics by measuring the absorption rate (the time of moisture absorption on the front and back sides of the fabric), the unidirectional transfer capability (the difference in the absorption and diffusion of liquids on both sides of the fabric), and the diffusion/drying rate (the diffusion rate of liquids on both sides of the fabric). The liquid water management tester consists of an upper and lower-centered liquid sensor with multiple probes. The liquid tube in the upper sensor drips a fixed concentration of salt water simulating human sweat evenly onto the fabric, and the sensor probes test the resistance between the different rings to reflect the absorption and diffusion of liquid in the fabric by the change in resistance, so as to obtain the ability of the fabric to absorb and diffuse sweat. A computer and corresponding software are usually required to see the test curves and data simultaneously.
3. Test principle of Moisture Management Tester
When a fabric sample is placed horizontally and liquid water comes into contact with its submerged surface, liquid water diffuses along the submerged surface of the fabric and passes from the submerged surface of the fabric to the permeated surface, and at the same time diffuses through the permeated surface of the fabric, and the water content changes as a function of time. After the test solution is applied to the water-soaked side of the sample, the dynamic transfer of liquid water is measured using sensors in close contact with the sample, and a series of performance indicators are calculated to evaluate the performance of the textile in terms of moisture absorption and dryness, perspiration, etc. So, the MMT test principle is easy to understand.
4. Test procedure of Moisture Management Tester
The sample is placed in the apparatus with the side in contact with the skin upwards, and a quantity of saline is poured onto the center of the side of the fabric in contact with the skin, simulating the process of sweating out of the body. The sensors on both sides of the sample measure their water conductivity in each ring (5 mm, 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm in diameter). After a 2-minute cycle of the test, the moisture and water conductivity of the fabric increased. The HD camera simultaneously records the movement of water and creates a synchronized curve image on the computer. Through a series of calculations, the moisture checking machine obtains accurate readings of the wetting time, water absorption rate, soaking radius, and diffusion rate of the fabric on the skin contact side, as well as the cumulative unidirectional transfer power and the overall liquid moisture management power (OMMC) of the fabric.
5. How to evaluate the Moisture Management Performance of the fabric?
In order to facilitate the analysis of the liquid moisture management capacity of the specimen, the test indices are converted into a tabular form (Table 1 below) on a scale of 1 to 5. Depending on the grade of the fabric and the index value, the fabric can be classified into 5 grades according to its liquid water management properties.
Table 1: All indices grading table
Graph 1:overall liquid moisture management test results for a particular fabric. (eg.)
The specimens exhibited excellent overall liquid moisture management as shown in the graph1 comparing water content versus time before and after treatment.
(The data from the graph)
The Transport Index and overall liquid moisture management capabilities or this new moisture testing, have attracted the attention of many technical fabric manufacturers. Studies have shown that using these numbers and the “fingerprint” provided by the liquid water management tester, users can classify fabrics into seven classes: water resistant, water repellent, slow absorbent/slow dry, fast absorbent/slow dry, fast absorbent/fast dry, water penetration, and liquid water management. Users can compare different fabrics using the indexes measured by the moisture management tester. At this point, they know which fabric is the right fabric for their environment and do not have to undergo tedious physical tests.
Liquid Moisture Management Testers have been adopted by fabric manufacturers and sports equipment manufacturers/retailers for new product design, and by some factories for quality control. The portable design of the liquid moisture management tester makes it an excellent marketing tool because it allows for live demonstrations and direct comparisons of the performance of different fabrics in front of the customer.
6. The application of the Moisture Management Tester multiplies.
The Moisture Management Tester, or moisture checking machine has been widely adopted by laboratories around the world. Most of the users are from the sporting goods industry, and they are fabric manufacturers or retailers. They have found significant utility in demonstrating the performance of their fabrics to end users. Those from the medical hosiery, tissue, sanitary napkin, and mattress cloth industries also showed a strong interest in the moisture management tester. Although they are not from the apparel manufacturing industry, they have found that the data provided by the MMT tester has played a significant role in their success.
Industry-standard organizations are also interested in the MMT tester. The American Association of Textile Chemists and Colorists (AATCC) and the American Society for Testing and Materials (ASTM) have also described the use of liquid moisture management testers in their recently published book, Liquid Moisture Management Technology Supplement.