3, laminated fabric
Laminated fabric combines the good breathable, waterproof, windproof and warm-keeping perfectly. It has an outstanding advantage. It uses the laminating technique to laminate the usual fabric with a high-tech membrane. It represents the highest level of the waterproof and breathable fabric.
At present, laminated fabric mainly has the TPU membrane, PES membrane, PTFE membrane, etc.,
To see from the structure, TPU and PES are non-micro pores. It uses the hydrophilic of polymer the transfer the sweat vapor out of the garments. This transformation is infected by the temperature and humidity. Only when the temperature and humidity is higher than outside, the water vapor can get out of the garments. The structure of the PTFE membrane is combined with micro-pores. The thickness of the PTFE membrane is usually between 25 um-35um. The open rate is up to 80%. There are more than 1 billion per square centimeter. The diameter is 700 times bigger than the molecule of the vapor, and 5000-20000times smaller than water drop. Then the vapor can get out from the membrane and the water can't get in.
To check from the test results, the main difference between TPU,PES and PTFE as below:
| number |
program |
TPU.PES membrane |
e-PTFE membrane |
| 1 |
breathable（g/m2.24h） |
2000—5000 |
1000—16000 |
| 2 |
Water-resistance（mm water volume） |
10000以上 |
10000以上 |
| 3 |
Temperature range（℃） |
–10℃--90℃ |
-150℃--300℃ |
| 4 |
Cauterization resistance |
bad |
perfect |
Therefore, the TPU,PES laminated fabric has advantage in casual garments( mainly cost advantage). And the PTFE laminated fabric can be suitable for a wide temperature, especially has advantage in spaceflight, military battle, outdoor sports, it is honored as the century fabric.
二、The theory of waterproof and breathable of the PTFE membrane
The performances of the waterproof and breathable of the PTFE membrane are decided by the structure of the membrane and lubricate performance etc. There are three parts of the structure of the membrane:
a. The open rate of the membrane and number of the micro-pores.
b. The shape, size and distribute range of the micro-pore of the membrane.
c. Three-dimensional structure of the membrane.
To check the membrane from the electron microscope: the surface of the membrane has a spider net structure. The state of the micro-pores is a usual fiber structure. PTFE membrane belongs to unsymmetrical membrane. The size of the pores of the face side and the back side is different.
The section of the membrane is a net structure. |
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Waterproof and breathable means that the water outside can't penetrate the membrane, but the sweat vapor can be penetrate out from the membrane in its vapor state. To check from the meaning of the word, waterproof and breathable is antinomy. But we can solve this antinomy considering the different size of the molecule of the vapor and rain drop. |
e-PTFE微孔薄膜电镜照片 |
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