PPR (polypropylene random), also known as random copolymer polypropylene (PPR), has good toughness, high strength, excellent processability, good creep resistance at higher temperatures, and has the unique high transparency of random copolymer polypropylene Advantages, can be widely used in the production of pipes, sheets, daily necessities, packaging materials, household appliance parts and various films.
PP-R pipe is also called three-type polypropylene pipe and random copolymer polypropylene. The random copolymer polypropylene can be extruded to form a pipe, and it can also be injection-molded into a pipe. Polypropylene random copolymer is also a kind of polypropylene. The basic structure of its polymer chain is modified by adding different kinds of monomer molecules. Ethylene is the most commonly used monomer, which causes changes in the physical properties of polypropylene. Compared with pp homopolymers, random copolymers have improved optical properties (increased transparency and reduced haze), improved impact resistance, increased flexibility, reduced melting temperature, and thus reduced heat fusion temperature ; At the same time, it is basically the same as homopolymer in terms of chemical stability, water vapor barrier properties and organoleptic properties (low odor and taste). Used in the fields of blow molding, injection molding, film and sheet extrusion processing, as food packaging materials, pharmaceutical packaging materials and daily consumer goods.
Brief introduction of cross-linked polyethylene pipe (PEX) pipe
Ordinary high-density polyethylene (HDPE and MDPE) pipes have linear knots in their macromolecules. The biggest disadvantage is poor heat resistance and creep resistance. Therefore, ordinary high-density polyethylene pipes are not suitable for transporting temperatures greater than 45 ° C. medium. "Crosslinking" is an important method for polyethylene modification. After the linear macromolecular structure of polyethylene is crosslinked, it becomes a PEX with a three-dimensional network structure, which greatly improves the heat resistance and resistance of polyethylene. Creep ability, at the same time, its aging resistance, mechanical properties and transparency have been significantly improved. The higher the degree of cross-linking, the more obvious these properties are improved. At the same time inherited the inherent chemical resistance and flexibility of polyethylene pipes. There are three commercialized PEX tubes. PEXa tube PEXb tube PEXC tube
PEX tube features
It has excellent heat and cold resistance, high heat strength at high temperature:
With excellent low temperature toughness:
Heating does not melt:
Superior creep resistance: Creep data is an important basis for product design and engineering selection. Compared with traditional materials such as metals, the strain behavior of plastics has a significant dependence on loading time and temperature. The creep characteristics of PEX pipes are almost It is one of the most ideal pipes in common plastic pipes.
Semi-permanent service life: After passing the test of temperature 110 ℃, hoop stress 2.5MPa, and time 8760h, it can be deduced that its continuous service life is 50 years at 70 ℃.