How to test the performance of functional textiles such as waterproof, moisture permeability, quick-drying and contact coolness?

Functional textiles are fabrics with features beyond those of regular textiles. They must provide warmth, coverage, and beauty. Some common functions are: anti-static, washable (non-iron), shrink-proof, moth-proof, waterproof, stain-resistant, wrinkle-resistant, and anti-pilling. Others are flame retardant, UV protection, far-infrared, electromagnetic shielding, and anti-bacterial properties..

Some of these special-function textiles have a single function. Others have several, making them multifunctional or composite.

Classification of Functional Textiles

Functional textile products are usually classified by:Fibre type、Structure、Performance、Purpose

Designers base functional textiles on their performance and purpose. We can divide them into these categories:

(1) Finishing textiles

Cotton, wool, silk, and linen fabrics. They are waterproof, wrinkle-free, and dirt-resistant. They also have anti-static, anti-corrosion, and mildew finishes.

(2) Protection function textiles

Anti-ultraviolet, radiation, flame retardant, high temperature, heat insulation, sound insulation textiles.

(3) Sensibility textiles

Cold-feeling, super soft, quick-drying, moisture permeability, high elasticity functional textiles.

(4) Health care textiles

Antibacterial, far infrared, negative ion health care and other functional textiles.

By function, there are: comfort, protection, health care, and easy maintenance. Also, there are intelligent systems.

(1) Comfort Textiles

Textiles should be comfortable and functional. They must:

Be moisture-permeable and breathable.

Absorb moisture and dry quickly.

Resist heat and moisture.

Provide warmth and a cool feeling on contact.

(2) Protective textiles

It can protect the human body and reduce harm. And it may be flame retardant, and anti-EM radiation, UV, and static. It may also be windproof and waterproof.

(3) Health care textiles

It has far infrared, negative ions, and other functions. They inhibit germs, mould, and other microbes. It can repel or kill harmful insects, prevent disease, and protect human health.

(4) Easy maintenance textile

Products with non-iron, anti-wrinkle, and easy-to-clean features can reduce upkeep. They are easier to clean.

(5) Intelligent textiles

In the external environment, changes with intelligent adjustment functions. These include: heat storage temperature, shape memory, and self-luminous fibres and their products. Also, tracking, positioning, and biomimetic functions.

Functional textiles test items

1. Antistatic performance

FZ/T64011-2012 Electrostatic Flocking Fabrics

FZ/T24013-2020 ‘Durable antistatic cashmere knitted fabrics’.

In evaluating textile products, test their electrostatic properties. Check the resistance indicators: volume, mass, surface, leakage, and inter-polar equivalent resistances. Also, test the electrostatic voltage, its half-life, and charge surface density.

Test indicators reflect different characteristics. Half-life shows the speed of electrostatic decay. Charge and charge surface density measure the friction from static electricity. Surface resistivity and point-to-point resistance show the conductive properties of strong and weak.

Enterprises often use 12703.1 to test textiles’ electrostatic half-life. It grades fabrics into A, B, and C.

Winter clothes often use anti-static textiles as fabrics. There are three main ways to make anti-static textiles. Use anti-static fibers, add wire filaments, or use anti-static finishing agents.

2. Waterproof and moisture permeability

Testing and Evaluation of Waterproof Performance of Textiles Hydrostatic Pressure Method

Anti-staining performance:

The “Staining Method” tests textiles for water repellency. The standard divides the anti-staining grade into 0-5. Grade 5 means excellent anti-staining performance. Grade 0 means no anti-staining performance. The higher the grade, the better the anti-staining effect of the textile.

Hydrostatic pressure resistance:

Hydrostatic pressure resistance simulates the waterproof performance of textiles in a rainstorm environment. The testing method used in the national standard is ‘Testing and Evaluation of Waterproof Performance of Textiles Hydrostatic Pressure Method’. The standard states that textiles must resist hydrostatic pressure. You must provide a resistance of at least 4kPa. At least 20kPa indicates good resistance. At least 35kPa indicates excellent resistance. The ‘Technical Requirements for Physical and Chemical Properties of Clothing’ says that, to be rainproof, hydrostatic pressure resistance must be at least 13kPa. Rainstorm resistance must be at least 35kPa.

Test principle:

The hydrostatic pressure on the fabric shows its resistance to water. Under standard conditions, rising water pressure exposes one side of the specimen. This continues until three seepage points appear on the other side. The team records the pressure at the third seepage point. Researchers use this value to evaluate the specimen’s waterproof performance.

Test equipment:

Intelligent hydrostatic pressure tester

3. Moisture absorption and quick drying performance

At present, the main test standards for moisture absorption and quick-drying performance are:

Test method for moisture-absorbing and quick-drying properties of textiles. Part 1: Single combination test.

Eval of moisture absorption and quick drying of textiles, pt 2: dynamic moisture transfer method.

AATCC 201-2013 Textile Drying Rate: Heated Plate Method

The dynamic moisture transfer method is easy to use. Its tests are thorough. It can test performance in combination, like moisture absorption and quick-drying. But, it lacks intuition. The single combination test method is best. So are the core suction height and drip diffusion time. They more directly test a fabric’s ability to quickly absorb and spread moisture.

AATCC201 Heated plate method is a common method for fabric drying rate testing. The contact heating plate is set at 37°C, the same as the human body. This simulates sweating on the skin surface. The fabric’s drying rate is from its evaporation rate. It is in contact with a set amount of water at the heated metal plate’s interface, at a constant temperature.

The test methods above require a test index for moisture absorption and quick drying. It must meet the standard, both before and after washing. The brand owner customizes the wash method and the number of washes, as noted in the test report. Only then can we call the products true moisture-absorbing and quick-drying ones.

Enterprises can choose assessment criteria based on their products. They can use their products’ traits to guide them. Textiles must pass all moisture tests, both before and after washing, regardless of the method used. Only then can we claim them as moisture-absorbing and quick-drying.

Test equipment: SmartDry intelligent drying rate tester

4. Warmth retention performance

Domestic tests use two main indexes to measure heat preservation. They are thermal resistance and heat preservation rate. The domestic product standards use the insulation rate to test a garment’s warmth. The thermal resistance is only in the method standards. Domestic garment standards rarely use it as an assessment index.

ISO158312004 ‘Clothing physiological effect of warmth test warm body dummy method’.

ASTMF12912010 ‘Clothing warmth test warm body dummy method’.

ASTM F1868-2014. “Test Method for Thermal Resistance to Moisture of Apparel Materials. Evaporative Thermal Plate Method.”

The thermal resistance of a cold weather garment is its ability to prevent body heat loss in the cold.

Clothing thermal resistance is its ability to resist heat transfer. It is due to the temperature difference across the clothing. It is the ratio of that temperature difference to the heat flow through a unit area of the clothing. The unit is m2 – ℃ / W. It is also expressed in an easy-to-remember unit: Crowe (clo).

Test Equipment: Thermal Resistance and Moisture Resistance Tester

Use the AtmoExplorer test chamber with a hot plate. It can test fabric thermal and moisture resistance.

5. Oil-repellent performance

It is more commonly used in oil and dirt repellent functional garments. Woven textiles can refer to ‘Technical Requirements for Physical and Chemical Properties of Clothing.’ They must pass the ‘Textile Oil-repellent Hydrocarbon Resistance Test.’ This will achieve an oil-repellent level of at least 4. Other types of textiles can refer to or set their own requirements.

6. Contact coolness performance

FZ/T73067-2020 Contact Cool Feeling Knitted Garments

Coolness means the skin must contact the textile. It must quickly dissipate heat from the skin’s surface. So, the textile must have good thermal conductivity and not quickly absorb heat. In other words, it must have the property of absorbing heat slowly and be able to dissipate it quickly. Two main methods make textiles cool. They use cool-sensitive fibres and finishes.

The standard ‘Testing and Evaluation of Instantaneous Cool Feeling Performance of Textiles in Contact’ sets a limit. It requires a cool feeling coefficient, qmax, of at least 0.15 J/(cm2-s) to use terms like ‘Cool Feeling’ or ‘Ice Feeling’. The main standard for textile cool feeling is FZ/T73067. And FZ/T73067-2020 ‘contact cool knitted clothing’ on the coolness coefficient of clothing is more demanding.

7. Ultraviolet protection performance

The Evaluation of Textiles for UV Protection is the only national method for testing textiles for UV protection. The standard specifies a test method for UV protection of textiles against sunlight. It also covers the level of protection, evaluation, and labeling. The standard allows a product to be called a UV protection product if its UPF exceeds 40 and T(UVA)AV is below 5%.

In recent years, a variety of functional textiles have emerged. The goal of textile technology is to improve performance, multi-functionality, and intelligence. The future of textiles will focus on safety, comfort, and health. Convenience and low carbon are also important.

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