1, the flow performance of PP-R is poor. Therefore, when selecting extruders, the ratio of length to diameter (L:D) of screws should be considered to be more than 28:1 (between 30-33), and the best extrusion die is low pressure extrusion die. At present, the domestic use of the more advanced is the German Barton Phil or its production line of production.
2, PP-R is a semi crystalline plastic, its pipe processing technology is relatively strict control, and the cooling temperature is especially important. The longer the cooling time and the higher the temperature of the cooling water will cause the shrinkage of the pipes. If the cooling is too low or too fast, the residual stress will be too large, so that the impact resistance of the pipes will be low when they are impacted.
3, the two important factors for the PP-R pipe fittings are the cooling of the die and the depth of the pipe socket. In addition, a metal embedded pipe should also have a certain requirement on the metal insert, otherwise it will cause water seepage at the connection during the use. Most of the problems in the PP-R system are in pipe and pipe fittings.