Polyester Water Blocking Yarn
Polyester Water blocking yarn technology development trend
In order to ensure the longitudinal sealing of the cable, to prevent water and moisture from invading the cable or corrosion of metal and optical fiber in the junction box, the loss of hydrogen, fiber, and electrical insulation caused by the sharp decline in the occurrence of the situation, at present, the following methods are usually taken to waterproof tide blocking:
1.In the fiber optic cable filled with thixotropic ointment, including hydrophobic (hydrophobic) type, water swelling type and heat expansion type and so on. All of these materials are oily materials, which have a large amount of filling, high cost, are easy to pollute the environment, and are difficult to clean (especially when the optical fiber cable is connected, they need to be cleaned with solvent), and the optical cable is too heavy.
2. The use of hot melt adhesive blocking rings between the inner and outer jackets is a low-efficiency and complex process that only a few manufacturers can achieve.
3. The use of dry expansion of water blocking material (absorbent expansion powder, water blocking tape, etc.). This method requires high process, large amount of material, high cost, and the weight of the optical cable is too heavy.
In recent years, the “dry cable core” structure has been introduced into optical cables, and it has been used very well in foreign countries. In particular, it has unparalleled advantages in solving the problems of large-capacity optical fiber cables such as overweight and continuous process. The water-blocking material used in this kind of "dry core" cable is polyester water blocking yarn. Polyester water blocking yarn can rapidly swell and form a gel, blocking the space in the water channel of the cable, thus achieving the purpose of water-blocking. In addition, the water-blocking yarn does not contain oily substances, and the time required for subsequent preparation can be greatly shortened, and there is no need to prepare wipes, solvents, and cleaners; the adhesion between the reinforcing yarn and the sheath of the outer layer of the optical cable is also good. It will not be reduced; in addition, the quality of the material is very light, so that the fiber optic cable is greatly reduced from its own weight and is therefore favored.
The traditional production of polyester water blocking yarn is made of powder and granular water-absorbent resin. However, there is a problem that it is easy to fall powder during production and use, and cause environmental pollution. Now we are developing new production processes. That is, the superabsorbent material is made into a soluble liquid, the yarn is coated, crosslinked, and the water-absorbent material is bonded to the yarn through a chemical reaction. The superabsorbent resin coating is fixed on the surface of the fiber; Physical adsorption, and second, condensation or exchange reaction between the superabsorbent resin and the functional groups on the surface of the fiber may occur during the high-temperature cross-linking process, resulting in a certain degree of chemical bonding and improving its adhesion. The water-blocking yarn made by the method has the advantages of small thickness, uniform coating, good swelling performance, high gel strength, light weight, and greatly avoids the powder dropping phenomenon.