High moisture permeability and high waterproofTPU membrane
Yes As for TPU, the textile industry is a market that people are not familiar with. Here TPU is attached to the base fabric, and it must provide protection, comfort and beauty to people wearing textiles. To this end, people have developed a “breathable” TPU. This polyether-type “high moisture permeability” TPU can be extruded into a film, which is compounded with a woven base fabric. This layer of TPU film acts as a barrier film that allows smooth breathing, that is, the moisture produced by the human body Moisture can escape, but no external liquid can penetrate. This breathability extends the application of TPU to some new areas: sportswear, sanitary products, outerwear, medical clothing, protective clothing, etc. These products are required to be both comfortable and comfortable for the wearer and the wearer. An effective protective barrier is established between the environment. The moisture permeability of this breathable TPU film is 5 to 6 times that of ordinary TPU films.
Thermoplastic polyurethane (TPU) is a strong, durable elastic material that has been dedicated to meeting the needs of meet many demands in the international market. The flexibility and diversity of this material’s properties are unmatched by other materials, such as outstanding wear resistance, strength and toughness, chemical and hydrolysis resistance, mildew resistance, low temperature flexibility, transparency, and color stability , easy to decorate, and can be processed using many plastic processing methods. So, it finds widespread use in wires and cables, footwear, automotive, healthcare, hoses and tubes, films and sheets, and more.
The moisture permeability of TPU is higher than that of PVC, although the moisture permeability is not At that time, TPU was the main reason for entering textiles, but this property was exactly what textiles wanted. Today, the moisture permeability of textiles has become very important, and TPU is still a good way to solve this problem.
A brief history of TPU application in textiles
TPU has been used as a coating on fabrics for nearly 30 years. Its earliest application was to replace PVC, which people have always considered to be “good in appearance and feel”. PVC lacks flexibility, plasticizer migration, wear resistance, poor low-temperature performance, and poor transparency. These just create opportunities for TPU to replace PVC. Although the cost is higher, TPU can solve the above problems. In addition, TPU provides an excellent soft feel, has a high surface gloss, and can be processed into a leather-like look and feel (footwear products).
Moisture permeability is a function of the textile structure that allows water vapor produced by the human body to pass through and be emitted. fall out, but at the same time do not allow liquid to pass through it. This property is expressed by the “water vapor transmission rate”, which is the flow rate of water vapor through a unit area in the direction perpendicular to the human body surface per unit time, expressed as the number of grams of water vapor per square meter per square meter in a specified time interval. ASTM E96B and 96E are methods for measuring it.
Nowadays, textile manufacturers believe that protection has a double meaning: one is to prevent external environmental factors from harming the wearer , The second is to prevent the wearer from contaminating the external environment, such as work clothes and surgical gowns in clean operating rooms. Under the conditions of working in a clean operating room, the purpose is to prevent human skin from coming into contact with those particularly sensitive electronic devices, while under the conditions of surgical operations, it is to prevent possible harm to the patient caused by microorganisms carried by the wearer.
In 1991, the U.S. Occupational Safety and Health Administration stipulated that all occupational personnel who come into contact with blood must carry out appropriate Protection to ensure that blood and other infectious materials do not come into contact with the skin and underwear of these workers. In other words, protective clothing must be worn. This regulation has prompted the establishment of some methods for evaluating the effectiveness of protective clothing in blocking liquids or viruses (ASTMES21 and ES22).
Although people have different opinions on what level of breathing ability is considered comfortable, textiles Both comfort and protective functions are very important requirements for textiles today. To this end, people have developed such a film that can prevent liquid from permeating and allow water vapor to permeate. In this way, the textile can quickly achieve a balance between the inside and outside, which can satisfy both comfort and comfort. And the dual requirements of protection.
Dense film and microporous film
There are two approaches to creating this comfortable and protective barrier structure, both of which can make the film or coating both water-permeable and water-permeable. �class=”MsoNormal” style=”text-align:left;line-height: 150%;”>D624C
D1044
84.1
0.07
68.3
0.08
Table 3. Moisture vapor transmission data of Estane58237 and 58245 extruded films
Method ASTM method Temperature, ℃ Relative humidity, % Estane58237Estane58245
g/m2/day
Vertical cup, water E-96B2350550650
Vertical Cup, desiccant E-96E235010009500
The data in the table are higher than those of standard polyester and polyether The base TPU is much better. Estane58237 can be compared with COPE and PEBA in terms of price and MVTR. The breathing ability of Estane 58245 is superior to all these materials and is close to that of microporous PTFE. This comparison is shown in Figure 3.
7. Markets and uses of high MVTR polyurethane
As mentioned earlier, this high MVTR thermoplastic polyurethane is widely used in the textile industry It has a vast market and numerous uses, as shown in Table 4.
8. Conclusion
High breathability is one of the main reasons why people recognize and are familiar with TPU. This material is manufactured into a dense film using common processing methods. In addition to good barrier properties, it also provides people with high comfort and beautiful appearance. The combination of these properties makes TPU film an ideal material for the textile industry.
Figure 3. Comparison of relative MVTR and cost
Table 4. Typical uses of high MVTR TPU in the textile industry
Use characteristics
Medical/surgical clothing blocks bacteria/virus, blocks liquid, MVTR, anti-puncture, and transparent
Medical bandage MVTR, elastic and soft and bendable, can be pasted on other polymers
Clean room clothing MVTR, static electricity dissipation ability, transparency, no gas release, no falling off
Sportswear, outerwear, MVTR, low noise, low temperature flexibility, compliance, windproof
Shoes, socks, gloves
Military clothing MVTR, chemical resistant Quality, low temperature flexibility, low noise, windproof, complianceX2VzwM
