Single-layer swelling nonwoven provides lasting protection for undersea cables

Amelie Riegsinger

Whether they are used for real-time data transmission or safe transportation of energy, undersea cables are indispensable. Lying at the bottom of the ocean, they must withstand a variety of stresses and strains: ship anchors, fishing nets, seaquakes, erosion or severe storms can all cause damage. In the event of cable damage, the penetrating moisture is quickly distributed within the fine capillaries in the interior. The affected areas must be replaced immediately and such repairs can quickly extend to 100 meters. Solutions from Freudenberg Performance Materials contain the damage and keep costs down.

Minimizing damage

The technology company’s highly developed swelling nonwovens already begin protecting undersea cables at the point of damage. The material reacts instantly on contact with water, swells into the fine spaces inside the undersea cable and seals them against moisture. This ensures that the length of the sections that need to be replaced is much shorter than is the case with unprotected cables. As a result, time and effort are reduced and enormous cost savings achieved.

The swelling principle is not limited to underwater applications. Freudenberg’s swelling nonwovens also provide optimum protection for cables exposed to increased moisture under the ground if they are damaged.

“Today, the nonwoven material in the cable plays a functional role. Increasing requirements in the high-voltage field combined with direct current are presenting us with new challenges. We are working in close cooperation with our customers to find solutions.”

Amelie Riegsinger, Sales Manager Energy at Freudenberg Performance Materials

1 gram of the polymer bonded to the nonwoven can absorb up to 300 grams of water, thus protecting damaged undersea cables from water penetration.
The total length of all undersea cables in the world’s oceans is 885,000 km.

Super absorber provides swelling function

A so-called ‘super absorber’ polymer powder, or SAP powder for short, is responsible for the nonwoven’s swelling function. One gram of the polymer can absorb up to 300 grams of water – and thus increases its volume many times over.

Optimal swelling with single-layer technology

The unique feature of this swelling nonwoven is above all the use of single-layer technology in its manufacture. In this process, the SAP powder is bound directly to the nonwoven. To achieve this, Freudenberg Performance Materials uses a water-soluble binder that dissolves immediately it comes into contact with moisture. This ensures precise swelling in the event of damage. In contrast, conventional products using the double-layer technique sandwich the polymer between two nonwovens. As a result, they risk not swelling quickly enough in the event of contact with water.