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I. Exceptional Chemical Resistance: The Passport for the Chemical Industry

The most prominent feature of polypropylene screws is their "excellent resistance to acids and alkalis." This is not an empty marketing slogan but is determined by their inert molecular structure. As a non-polar polymer, PP has a stable structure that offers strong resistance to most polar chemical substances, particularly aqueous solutions of acids, alkalis, and salts.

Application Scenarios: This makes them the preferred choice in fields such as chemical processing, electroplating, water treatment, and environmental protection engineering. Whether in pipelines or containers handling corrosive chemicals like dilute sulfuric acid, hydrochloric acid, or sodium hydroxide, or in equipment长期暴露于潮湿、盐雾弥漫的海洋环境中, polypropylene screws remain unfazed. They avoid the risks of rapid corrosion, rusting, and even failure that metal screws face, thereby ensuring the sealing integrity and structural safety of the entire system.

Comparison with Nylon: Although nylon also offers certain corrosion resistance, its molecules contain amide groups. Under the long-term influence of strong acids or alkalis, its molecular chains can undergo hydrolytic degradation, leading to a loss of strength. Polypropylene, in contrast, typically performs more stably and durably in this regard.

II. Ultimate Lightweight & Low Density: Born for Weight Reduction

Polypropylene has a density of only 0.90~0.91 g/cm³, making it one of the lightest common general-purpose plastics—even lighter than water. This characteristic gives PP screws an unparalleled advantage in lightweight applications.

Application Scenarios:

• Aerospace and Transportation: In these fields, where every gram counts, reducing the weight of every component translates directly into improved energy efficiency and extended range. Using PP screws to replace metal or heavier plastic screws can effectively reduce the overall weight of equipment.

• Portable Devices and Packaging: For frequently moved or handheld electronic devices, instruments, and high-end packaging, PP screws provide sufficient fastening strength while adding almost no extra weight, enhancing product portability and the user experience.

III. Cost-Effectiveness and Processability: A High-Value Choice

Polypropylene is a bulk product of the petrochemical industry, with widely available raw materials and low cost. Furthermore, it offers good injection molding performance, enabling high production efficiency and low rejection rates. This makes polypropylene screws one of the most cost-effective options among all plastic screws, highly suitable for large-scale, cost-sensitive applications.

Inevitable Limitations: Utilizing Them Wisely Requires Clear Understanding

As noted, polypropylene screws are not perfect. Their most significant shortcoming is their "relatively poor rigidity and mechanical strength compared to nylon." This is a critical point that must be clearly understood during selection.

• Mechanical Strength: The tensile strength, flexural strength, and hardness of PP are significantly lower than those of Nylon and POM. This means it is not suitable for applications with high shear forces, impact loads, or continuous vibration. In fastening applications requiring high preload, PP screws may experience creep, leading to clamp load relaxation and connection loosening.

• Toughness: Unlike the good toughness of Nylon, PP material can become brittle at low temperatures, with reduced impact resistance, making it prone to brittle fracture.

• Temperature Resistance: The long-term service temperature for polypropylene typically does not exceed 80°C, with short-term tolerance only around 100°C. Its melting point is approximately 160-170°C. Consequently, it is completely unsuitable for high-temperature environments, such as components near heat sources or engines.

Core Application Areas: The Wisdom of Leveraging Strengths and Avoiding Weaknesses

Based on these characteristics, the core strategy for applying polypropylene screws lies in "leveraging their strengths and avoiding their weaknesses."

1. Guardian of Chemical Corrosion Protection Equipment: This is the main domain for PP screws. Used in non-primary load-bearing structures like storage tanks for corrosive media, ventilation ducts, wastewater treatment equipment, and chemical instrument enclosures, they provide long-lasting and reliable sealing and fastening, with a service life far exceeding that of ordinary metal screws.

2. Ideal Partner for Light-Duty and Decorative Structures: In applications with low mechanical strength demands, such as internal wire clips in chassis and cabinets, fastening for lightweight partitions, toy models, and household appliance housings, PP screws get the job done while controlling cost and weight.

3. Sanitation Soldier in the Food and Medical Industries: Food-grade and medical-grade polypropylene materials comply with relevant health and safety standards. They are non-toxic, odorless, and resistant to disinfectant cleaning, making them commonly used in food processing equipment, medical device housings, pharmaceutical packaging, and other areas with stringent hygiene and anti-contamination requirements.

4. Insulator in Specific Environments: Like most plastics, PP is an excellent electrical insulator and can be used in electrical equipment where insulation is required but the high strength of nylon is unnecessary.