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Water Expansion Rubber Sponge Tape EP-EWS【Sponge type】
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Solid-type, i.e. ordinary rubber, water expandable rubber sealants are commonly used. On the foundation of their materials and technologies, we have developed a new sponge-type product.

- Sponge tape requires less tightening pressure during installation.
- With its water expandable feature, it has excellent water sealing performance.
- Designed to be lightweight, it is easy to install securely, when used with the dedicated adhesive, allowing users to be unconcerned about it falling off.

Types and Shapes.

Typical cross-section

● If you desire a size other than those shown on the left, please contact us.

Basic properties

Test item Unit Measured value Test method
Specific gravity - 0.5 JIS K 6268
Hardness - 50 JIS K 6253
(Durometer E)

Compression rate


Using EP-EWS test samples in the dimensions mentioned below, the relationship between compression rate and compressive stress was measured.
Tape dimensions:
15 mm H x 10 mm / 20 mm (trapezoid)
10 mm x 20 mm (rectangle)

Rate of volume change of in immersion with water


EP-EWS samples were immersed in constant temperature baths with water temperatures set between 1 and 5 °C and at 15 °C to measure the rates of change of thickness and volume.

Water pressure resistance / test results

●Immediate water pressure resistance test

EP-EWS samples with dimensions of 15 mm H x 10 mm / 20 mm (trapezoid) were secured using an adhesive on the inner circumference of a disk-shaped jig as illustrated in the diagram at right and the sponge compression rate was adjusted with spacers of different heights.In addition, water pressure was applied inside the jig to observe if water leaked after three minutes.

●Test equipment

Water pressure (MPa) Compression rate (%)
20% 40% 50% 60%
0.2 Water leaked Water leaked No water leakage No water leakage
0.4     Water leaked No water leakage
0.6       No water leakage
0.8       No water leakage
1.0       No water leakage

Results of temporal water pressure test


Using EP-EWS test samples in the dimensions mentioned below, the relationship between compression rate and compressive stress was measured.
Tape dimensions:
15 mm x 10 mm / 20 mm (trapezoid)


EP-EWS samples were immersed in constant temperature baths with water temperatures set between 1 and 5 °C and at 15 °C to measure the rates of change of thickness and volume.

●Test method

* Adjust the spacer height in advance to ensure EP-EWS is not compressed.
Immersion temperature: 1 to 5 °C and at 15 °C
Immersion period: 49 days (maximum)

The test observed water pressure levels up until the samples, which began uncompressed, exhibited enough water-induced expansion in the long-term test to demonstrate their sealing performance based on expansion pressure.

●Test equipment