(A) Selection and characteristics of rubber material are rubber hose during use subject to external forces and prolonged contact with a variety of soil, water. Therefore, the requirements of a rubber material must have excellent flexibility, compression, high tensile strength, elongation, and wear and tear of high performance, wide temperature range. Some products also requires alkali-resistant garden, salts and other inorganic and resistance to various mineral oils, animal and vegetable oil, used in underground engineering must also have some anti-Xia performance. - Like a big rubber commonly used natural rubber, styrene-butadiene rubber, chloroprene rubber, EPDM rubber, rubber properties in a variety of different, and therefore selection of different rubber material according to different requirements. Domestic products using natural rubber and butyl rubber more nitrogen, in actual use have achieved a good sealing effect. Germany using SBR more. At home and abroad has gradually push / use anti-aging properties excellent resistance to high and low temperature water for a long time and compressive deformation smaller EPR. Mechanical ii) trees gum material properties of the sealing effect of shadow power rubber water-sealing effect of the merits of the physical and mechanical properties of rubber materials are closely related. Use of the environment, the installation method of the stress state rubber seal member has a direct impact. Embedded-type sealing control as pieces of plastic, it is necessary to withstand the temperature when pouring concrete strength and resist pounding small pointed top thorn, but also to bear in the course of settling mutual aid between mixed soil structure, torsional , tearing and so on. If you can not adapt to these external factors, rubber water-stop action, it will have damage caused by leakage, loss of sealing effect. For long-term pressure on the rubber water-stop distortion, different rubber hardness, sealing effect is different. The higher the hardness, the greater the compression stress; compressive deformation on the same conditions, when the rubber hardness increased south, the compressive stress increases rapidly. So, at a lower compression ratio, also have a high water capacity; rubber hardness lower the compressive stress increases slow invasion, so the compression rate is low, its impermeability to Qiang. But this one is that of rubber so that the higher the better. If the rubber hardness is too high. Its less flexible, low elongation; when the compression rate increases, rubber sealing parts, the greater the force, often prone to cracking, damage rubber material, thereby reducing or losing the sealing effect. Currently, the hardness of the rubber water-stop rubber material (Shore A) is generally controlled between 50 ° and a 70 °, through the water-swellable rubber hardness is generally around 38 ° a 50 °.