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The Fermapor CC foam seal made of polyurethane is robust and ice water-resistant. (Source: Sonderhoff)

22. November 2018

Sonderhoff Fermapor CC foam seal with low water absorption and high ice water resistance

The FIP CC technology (Formed-In-Place Closed-Cell) newly introduced to the market by Sonderhoff combines the high water resistance of the silicone world with the attractive material costs of the polyurethane world. The newly developed Fermapor CC foam seals are polyurethane-based, two-component, room temperature crosslinking systems that form a very fine-cell, predominantly closed-cell soft foam seal with the FIP CC foaming process. The big advantage is that they have very low water absorption and cure without an oven or humidity.

In contrast to comparable mixed-cell seals, the closed-cell foam seal requires less compression with the same sealing performance. The robust, mounting-resistant surface of the CC foam seal withstands possible mechanical stresses in the parts’ handling. Even after damage to the seal surface, the water absorption changes only slightly. The CC seal made of polyurethane is weatherproof and also ice water-resistant.

The Fermapor CC foam seal is particularly water repellent even under cold water conditions (up to 1 °C) and retains its sealing properties. With 24 h ice-water storage (1 °C) of a 40 % compressed foam seal, the volume increase caused by the water absorption is only ~ 1%. In contrast to the predominantly closed- cell CC foam seals, the values for the gravimetric as well as volumetric water absorption of mixed-cell standard PU seals deteriorate drastically in falling temperatures of up to 1 °C. At 40 % compression and cold water (1 °C), the volume of a conventional PU foam seal increases by a factor up to 10 times higher due to water absorption.

The factors low water affinity of the raw materials used, the very fine cell structure and the closed cell structure have a significant positive influence on the low water absorption of the Fermapor CC foam seal at 1 °C. Due to the capillary depression, the very fine cell structure of the hydrophobically adjusted CC foam seal offers the advantage that water from very small cells is pushed out to a greater extent than from the capillaries of a coarse cell structure.

"This makes Fermapor CC significantly different from conventional polyurethane foam seals," says Peter Fischer, Head of Marketing, Sonderhoff Holding GmbH.


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