... machine used 3,Liquid 669 Hydrophilic Single Liquid Type PU Foaming AgentProduct DescriptionPu foaming agent: Single-liquid model, simple construction, hydrophilic, when ... swelling can be combined with (gravel, sand, cement.), into the layer which can seal and cracks in the wall, swelling coefficient ... water, sea water, waste water and so on. 669 Hydrophilic Single Liquid Type PU Foaming Agent