*This article is about one of sodium polyacrylate’s applications – water blocking material in waterproof tape and waterproof ointment (in cable).
Sodium polyacrylate is an absorbent material that can absorb & block water up to hundreds of times its own weight.
Sodium polyacrylate is a highly coveted product as far as the manufacture of water-proof tapes and ointments for all sorts of cables are concerned; even, optical fiber cables use it.
Cables and optical cables are the transmission carriers of electricity, communication, etc., and are very sensitive to water. There is a danger of electric leakage when the cable enters the water, and the optical cable cannot transmit information when it enters the water.
SAP is used in cables and optical cables erected or laid underground (especially for submarine laying).
The principle is to make the super absorbent resin layer into waterproof tape and wrap it on the cable core as a waterproof layer.
Once the outer casing is cracked or damaged, water enters the waterproof layer, and the superabsorbent resin contained in it absorbs water and swells to seal the damaged part, which can prevent water from invading the cable and prevent the cable from being damp and reducing reliability. Thereby improving the safety of the cable, and prolonging its service life.
According to the introduction of the Stockhausen company, the cost of the cable with SAP waterproof treatment is low, and the performance is equal to or even better than the traditional treatment method.
At present, the application of SAP in this area is expanding, especially in the water-stop and water-proof materials of optical cables
material. The SAPs used as water-stop and water-repellent materials for optical cables mainly include saponified hydrolyzates of starch acrylonitrile graft copolymers, and starch-acrylate graft copolymers, and the like.
In addition, in the electronics industry, SAP can also be used for temperature sensors, moisture measurement sensors, leakage
Water detector, photochromic element, photo-responsive element, body electrode, ultrasonic probe, etc.
1. Strong expanding capability
Once the outer layer of the cable was broken, sodium polyacrylate would quickly absorb water and be expanding (to block water). This process will protect the conductor in cables from moisture.
So the expanding capability is the most important point of sodium polyacrylate for cables.
2. Smaller particle size
In general, the smaller particles of sodium polyacrylate bring a faster absorbing rate.
Sodium polyacrylate's particle size can be 10-200 mesh. And cable type should be more than 50 mesh.