With the rapid development of communication technology, the application fields of optical cables are expanding. Due to the continuous improvement of environmental requirements for optical cables, the quality requirements of materials used in optical cables have also increased. Optical cables need to take a variety of adequate water measures, mainly because water enters the optical cable to decompose hydrogen, which increases the transmission loss of the optical fiber, reduces the performance of the optical cable, and shortens the life of the optical cable.
Water blocking tapes have become a common water blocking in the optical fiber cable material, this material is usually a combination of tape, yarn and layer. Its function is to seal, waterproof, moisture-proof, buffer and protect in order to prevent water from penetrating into the cable core longitudinally.
The water blocking function is due to the high absorption material (water blocking agent) contained in it that swells in contact with water. When the water blocking agent encounters water, it can quickly swell to a large volume of gel (the water blocking agent can absorb water). Hundreds of times of itself) so as to prevent the growth of water number, prevent water from continuing to infiltrate and diffuse, thereby preventing the growth of water trees, and prevent water from continuing to infiltrate and diffuse.
There are many ways to classify optical cable water blocking tapes, which can be classified according to their structural quality and thickness. The general structure can be divided into double-sided water blocking tapes, single-sided water blocking tapes, and film-coated water blocking tapes.
To meet the demand of optic fiber cable, the water blocking tapes of optical cable must have the following requirements:
1) The appearance of fiber distribution is uniform, the surface is flat without wrinkles, creases and breakages, and the web edges are free of cracks. The composite material has no delamination and powder drop. It has certain mechanical strength and is suitable for the needs of cable formation;
2) Uniformity, good repeatability, stable quality, no delamination or dust generation when cabled again;
3) High swelling pressure, fast swelling speed and good gel stability;
4) Good thermal stability, adapt to various subsequent processing work;
5) Good compatibility with other materials of optical cable, oxidation resistance, etc.