In the previous period, a kind of pipe called PP-C appeared on the domestic market. Many people were confused about the differences between PP-C, PP-R and PP-B, causing many misunderstandings and confusions. In fact, PP-C is a collective name for copolymerized polypropylene. PP-R and PP-B, which have quite different performances, belong to the PP-C category, so it is impossible to have PP-C pipes in the standard. There are three types of polypropylene hot and cold water pipes: PP-R, PP-B, and PP-H. What is called PP-C pipe on the market is actually PP-B pipe, and its raw material is the special material for pipe of block copolymer polypropylene. PP-B pipe is a kind of hot and cold water pipe, which is relatively cheap, but there is no small gap between heat resistance and pressure resistance and PP-R pipe, so it cannot be confused.

　　It should be said that all domestic raw materials provided, including those sold in the domestic market in South Korea, are not "special materials for random copolymer polypropylene pipes" stipulated by international standards. Domestic pipe manufacturers should pay attention to distinguish their scope and conditions when selecting them.

　　Attachment: The naming and connotation of raw materials for polypropylene series plastic pipes:

　　[ISO / DIS 15874-1999] stipulates the naming of polypropylene and propylene copolymer materials (named according to the chemical composition, molecular structure and production process of propylene polymers):

　　PP-H (Poly Propylene Homopolymer) —propylene copolymer (type I)

　　PP-B (Poly Propylene Block Copolymer) —propylene block copolymer (type II)

　　PP-R (Poly Propylene Random Copolymer) —propylene random copolymer (type Ⅲ) Types Ⅰ, Ⅱ, and Ⅲ are classifications of special raw materials for polypropylene series pipes, and they are not the first, second, and third generations. Generation; it does not mean that the third generation is better than the second generation or the second generation is better than the first generation, so that the latter replaces the former. They are special materials for pipe series with their own characteristics.

　　Definition in polymer chemistry:

　　A macromolecule formed by the polymerization of a molecular monomer is called a homopolymer. A macromolecule formed by polymerizing two or more kinds of molecular monomers is called a copolymer. It can be seen that PP-H is a homopolymer polymerized from Propylene, a molecular monomer, while PP-B and PP-R are copolymers polymerized from Propylene and Ethene. (Poly Propylene Copolymer is PP-C).