Grandpipe GRP pipes are produced by using continuous advancing mandrel process that represents state-of-the-art in GRP pipe production. Product range bu this method is 300 – 4000 mm diameter. Main raw materials used in the process: Glass fiber, polyester resin and silica sand. Also surface mat, catalyst, chemical additives and accelerators are included inside of pipe structure.
Main principle of continuous advancing mandrel process is to use glass fiber reinforcements in the circumferential direction of pipe. Hoop rovings provide strength to GRP pipe against circumferential and external loads. Chop rovings inside of pipe structure empower the strength against longitudinal loads and multi direction loads. Silica sand used in sandwich structure of pipe is the main parameter to obtain exact pipe stiffness. Polyester resin used as main matrix of pipe is very important raw material that combines all pipe layers and effects chemical life. In some special cases, vinylester and other resins can be used instead of polyester resins.