Raw materials specified for PPH chemical pipelines

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Development of PPH raw materials and applications in chemical pipelines. PPH is a high-molecular-weight homopolymer of polypropylene; it is available in forms with high melt flow rates (MFR: above 3) and low melt flow rates (MFR: 0.18–0.3). PPH with high melt flow rates is mainly used for wire drawing purposes and cannot be utilized in the production of extruded pipes, fittings, sheets, etc. What we are referring to here is PPH raw material with a low melt index. This type of PPH raw material has a wide range of applications. Next, we will discuss its functional features, product advantages, and historical development. Product features: PPH 4100 is a high-molecular-weight, low-melting-index homopolymer polypropylene. This material must undergo β-modification to possess a uniform and fine β-crystalline structure, which not only confers excellent chemical resistance, high-temperature resistance, and good creep resistance, but also yields outstanding impact resistance at low temperatures. β-PPH materials were used in pressure-bearing pipeline systems in the 1980s, and they are still in good use today. The performance characteristics of β-PPH pipes also include excellent corrosion resistance, particularly outstanding resistance to long-term creep and stress cracking, as well as good pressure resistance, resistance to surface wear, and weldability. Due to its unique crystal structure, the β-form PPH is generally composed of radially oriented parallel flake crystals, which are connected to each other through curling; this improves upon the poor toughness, rigidity, wear resistance, and corrosion resistance of ordinary PP. It possesses good impact resistance and heat resistance, as well as high long-term creep strength and pressure resistance. Therefore, the pipes produced from β-PPH material can be used in systems for transporting and storing chemical fluids, and are widely applied in industries such as steel metallurgy, petrochemicals, electronics, pharmaceuticals, food, and semiconductors; their operating temperature can reach 95 degrees. Chemical pipeline systems require pipes that are safe, reliable, capable of continuous operation, and have a long service life. Since they are primarily used to transport industrial wastewater, sludge, and corrosive substances, the chemical resistance and wear resistance of the pipe materials are crucial for the proper functioning of these systems. The β-crystal structure improves the mechanical properties of PPH material, enhances its impact resistance, and reduces its sensitivity to notches. In addition, it offers good chemical resistance, high-temperature resistance, and excellent creep resistance; therefore, β-PPH pipes meet the requirements of the chemical pipeline industry quite well. The production volume of β-PPH accounts for only a small fraction on a global scale. Due to its excellent mechanical properties, outstanding chemical resistance, good heat resistance, impact resistance, and favorable creep resistance, β-PPH will become an important material in industrial applications. As awareness of β-PPH increases, its use worldwide is expected to grow. However, at present, some manufacturers use ordinary PP instead of β-PPH in order to maximize profits, which poses significant safety risks to customers and society. Overview of the development of β-PPH chemical pipelines in China: Ordinary PP pipes exhibit excellent rigidity, wear resistance, and corrosion resistance, but their impact strength is relatively low. β-PPH overcomes the weakness of PP materials in terms of toughness; it has a higher degree of crystallinity, as well as better heat resistance, long-term creep resistance, and pressure tolerance. Therefore, it can be applied to transportation and storage systems for chemical fluids in industrial fields such as electronics, pharmaceuticals, chemicals, food, semiconductors, and steel. At present, the development of the β-PPH industry for use in the chemical sector in our country is not standardized. Firstly, there are a lack of appropriate **standards**; secondly, there is a shortage of β-PPH raw materials domestically. Additionally, many manufacturers use ordinary PPB to reduce costs, which does not meet the requirements for use in chemical pipelines. The safety and quality risks associated with using such pipelines to transport chemical fluids at temperatures of 80°C to 95°C are evident. Overview of the development of β-PPH filter plates in China: There are dozens of companies in China that produce filter plates. Due to the lack of **standards or industry standards in this sector, as well as the large variety of filter plate types, competition within the industry is fierce. As a result, the materials used in their production are quite complex. Lower-quality filter plates are typically made by blending homopolymer powder with calcium carbonate or glass fibers. Different types of filter plates require different properties from their raw materials. β-PPH material is mainly used in the production of diaphragm filter plates that can withstand high temperatures and pressures. The dimensions of these filter plates range from 250×250 mm to 2000×2000 mm, with a maximum thickness of 100 mm. The maximum pressure they can handle is 4.0 Mpa, and the highest operating temperature is 110°C, allowing them to meet the needs of various users.