In the construction process of PP pipe materials, different laying methods result in two types of setups: expansion joint placement and pipe sleeve placement. PP pipes commonly use loose soil anti-freezing methods and insulation materials to prevent freezing. Before finishing work each day, regardless of whether the trench is fully excavated, a layer of loosened soil is left to prevent freezing. Insulation materials such as straw mats or straw curtains are then placed over trenches requiring excavation or those already excavated to ensure the soil base for PP pipes remains unfrozen. For a freezing depth of 25 cm or less, a standard medium-sized excavator is used. For a freezing depth exceeding 40 cm, a soil loosener can be attached to the rear of a bulldozer to break through the frozen soil layer.
PP pipe materials and dyes are organic compounds that can dissolve in the colored resin; pigments are generally inorganic compounds, which are not soluble in the coloring medium. Their coloring properties come from the high dispersibility of their particles, which are scattered in the colored medium. Their refractive index differs significantly from that of the matrix, absorbing some light and reflecting another part, creating a visual color. Pigments not only provide coloring to plastics but also serve as fillers and stabilizers. According to the needs of building PP pipe usage and molding processing, we sometimes also add lubricants, antistatic agents, foaming agents, flame retardants, and antimold agents.
When handling PP pipe materials, handle with care to avoid oil stains, and strictly prohibit any violent impacts. Do not touch, throw, roll, or drag against sharp objects. Ensure that the PP pipe materials provided during construction meet the design specifications and are accompanied by product manuals and quality certification. Always conduct a technical assessment or re-inspection of the PP pipe materials before use, and avoid any materials with quality discrepancies or signs of damage. Do not select PP pipe materials that have rough surfaces, molding defects, uneven colors, impurities, or poor printing quality.
PP pipes come in white, gray, and green colors. Generally, recycled plastic cannot produce white, hence the common belief that white pipes are superior, which is rather one-sided. With the advancement of technology, color is not the criterion for determining the quality of PP pipes. Appearance alone does not suffice. The primary material of PP pipes is polypropylene; high-quality pipes are odorless, whereas subpar ones have a peculiar smell, likely due to the addition of polyethylene instead of polypropylene. Under rated temperature and pressure conditions, PP pipes can be safely used for over 50 years.
