It’s essential that Dubo products are stored correctly. In the right conditions, the shelf life is usually very long. Ideally, Dubo products should be stored at around room temperature with normal humidity (40% to 60%). Dubo retaining washers are made of polyamide. This is a hygroscopic material, which absorbs and releases water in a reversible process. Parts made of this material tend to achieve a state of equilibrium with the humidity around them. For practical purposes, the saturation state after immersion in water and the state of equilibrium in a standard atmosphere (DIN 50014: 23 °C, 50% relative humidity) are generally taken into account. The mechanical properties of Dubo retaining washers, especially flexibility and minimum tensile strength, are significantly affected by the water content. In a standard atmosphere of 23 °C and 50% relative humidity, the degree of water saturation of polyamide is around 2.5%. To apply Dubo retaining washers in the best conditions, it’s therefore important that the polyamide has a water content of approximately 2.5% in a state of equilibrium. Deliberately modifying the properties of plastics through the controlled absorption of water is called conditioning. Conditioning is used to rapidly reach the state of equilibrium that can be expected in a part during subsequent use. Moulded parts in polyamide only achieve their elastic properties and definitive dimensions after conditioning. During production, our washers are conditioned by immersion in water. If washers are stored in relatively dry conditions, subject to large temperature fluctuations or exposed to high levels of UV, they will lose moisture. Dry washers may become very brittle. This effect can easily be reversed by immersing them in water again for some time (48 hours), until they are fully saturated. Since the quality and functionality of our products are affected by their water content, we recommend Dubo products are stored in appropriate conditions as described above.