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Clear Poly Tarps Tells You How Waterproof Material Is Water Repellent
- Jun 09, 2017 -

  1, Young's formula

    A drop of liquid drops on the solid surface, assuming that the surface is perfectly flat, the droplet gravity is concentrated at one point, and the amount of the field is ignored. Due to the surface tension (Ys) of the fibers in the fabric, the surface tension (YL) of the liquid, and the interfacial tension (YLS) of the solid, the droplets form a variety of shapes (from cylindrical to fully paved ). In addition to the night to completely flat, the droplets in the solid surface is in equilibrium, A point to receive the role of gravity.

    The angle 0 is called the contact angle. When 0 = 00, the droplet is on the solid surface, which is the limit state where the solid surface is wetted by the field; when 0 = 1800, the droplet is cylindrical, Ideal not wetting state. In the water repellent finishing, the surface tension of the droplet can be regarded as a constant. Thus, the field can wet the surface of the solid, and go with the surface of the solid in the bank of the lotus leaves the late relay tension. From the alleged requirements, the greater the contact angle 0 is more conducive to the loss of water droplets, that is, the smaller the better.Clear Poly Tarps

2, fabric adhesion work

    Since Ys and YLS are practically almost impossible to measure directly, the contact angle 0 or cos0 is usually used to directly assess the degree of wetting. However, the contact angle is not the cause of wetting, and the actual result is that there is a cohesive work that also indicates the relationship between the interaction and the degree of wetting.Clear Poly Tarps

    YL and cos0 that indicate adhesion work can be measured, so the formula has practical significance. Similarly, the interface on the unit area of the liquid beads split into two liquid beads when the required work for the 2YL, can be called the liquid of the cohesion. From the formula, the contact force increases, the contact angle decreases, when the adhesive force is equal to the cohesion, that is, the contact angle is zero, which is the liquid in the solid surface completely paved, because cos0 can not exceed 1, so even if the adhesive Greater than 2YL, the contact angle remains intact. WSL = YL, then 0 is 900. When the contact angle is 180 °, WSL = O, indicating that there is no opacity between the liquid and the solid, but because of the number of hatchback there are some adhesion, so the contact angle is equal to 180 ° never found, can only get some An approximate situation, such as an angle of 160 ° or more. The following are the same as the "

3, the critical surface tension of the fabric

    Since the solid surface tension is almost impossible to measure, in order to understand the wettability of the solid surface, it was measured his critical surface tension. Although the critical surface tension can not directly represent the surface tension of the solid, but that the size of Ys-YLS, but it can explain the solid surface is wetting difficult. But it should

    It is noted that the determination of critical surface tension is an empirical method and the range of measurements is very narrow.Clear Poly Tarps

    It can be seen that, in addition to cellulose, the critical surface tension of other substances are taxed by the surface tension is small, so they have a certain degree of water repellency, which one CF3 maximum, one CH the smallest. Obviously, with a larger contact with the delivery of smaller critical surface tension of the material with who finishing agent, can get a better water repellent effect.Clear Poly Tarps