In many fields such as electronic manufacturing and aerospace, electrostatic protection is crucial, and INCHR@ESD plastics have become the focus of the industry with their unique electrostatic dissipative properties. Among them, resistance value, as the core indicator to measure its electrostatic protection ability, contains a wealth of technical secrets.
Resistance value: the key point of INCHR@ESD plastic electrostatic dissipation ability
Classification and applicable scenarios of resistance value
INCHR@ESD plastics can be divided into the electrostatic dissipative type and conductive type according to resistance value. The surface resistance value of electrostatic dissipative plastics is usually in the range of 10^6 Ohms – 10^11 Ohms. This feature effectively prevents static electricity accumulation. The surface resistance of conductive plastics is less than 10^6 Ohms, and they have the ability to quickly conduct static electricity to the ground, and quickly eliminate static electricity.
Core factors affecting resistance value
- Conductive filler: Conductive filler is the crucial factor influencing the resistance value of INCHR@ESD plastics. The shape, particle size, and additional amount of different types of conductive fillers such as carbon black, carbon fiber, and metal powder have a significant impact on the resistance value. Generally, the more filler is added, the denser the conductive path is, and the lower the resistance value is; the larger the aspect ratio of the filler, the easier it is to form an efficient conductive network, further reducing the resistance value.
- Plastic matrix: The characteristics of the plastic matrix should not be ignored. The polarity, crystallinity, and molecular chain structure of the matrix will directly affect the dispersion state and interaction of the conductive filler. The polar plastic matrix has good compatibility with the polar conductive filler, which can promote the uniform dispersion of the filler and lay the foundation for stabilizing the resistance value.
- Processing technology: Process parameters such as temperature, pressure, and shear force during the molding process, like an “invisible hand”, change the distribution and orientation of the conductive filler. In injection molding, too high an injection speed may lead to uneven distribution of the filler, resulting in fluctuations in resistance value; during extrusion molding, reasonable shear force can make the filler orderly arranged along the extrusion direction and optimize the longitudinal conductivity.
Accurate test method for resistance value
- Surface resistance test: Using the high resistance meter method, by placing electrodes on the surface of INCHR@ESD plastic and applying voltage, the surface current is measured to calculate the resistance value, which directly reflects its surface electrostatic dissipation ability.
- Volume resistance test: The three-electrode method is used to measure the current flowing through the sample volume at a specific voltage.
Control the molding technology: ensure the stability of the resistance value of INCHR@ESD plastics
The resistance value stability of INCHR@ESD plastics is closely related to the molding process, and the stability is ensured by accurately controlling the key links of different molding processes.
Injection molding
- Optimize injection parameters: reasonably set the injection speed to avoid melt turbulence and ensure smooth mold filling; according to the type of plastic and product structure, accurately control the injection temperature and pressure. For example, for ESD-PP plastics, the injection temperature should be controlled at 180-220℃ and the pressure should be maintained at 80-120MPa to ensure uniform dispersion of conductive fillers.
- Mold design optimization: according to the shape and size of the product, carefully design the gate position and number to make the plastic melt flow evenly in the mold.
Extrusion molding
- Select screws: Select screws with scientific design and high processing precision, such as gradient screws, to ensure that the plastic is subjected to uniform shear force during the extrusion process, and to achieve uniform mixing and orientation of the conductive filler.
- Cooling process optimization: By adjusting the temperature, flow rate, and time of the cooling medium, such as ESD-PE pipes use 20-30℃ spray cooling water.
Blow molding
- Strictly control molding parameters: According to product requirements, strictly control the stretch ratio (generally 2-4) and the blowing ratio (usually 3-6) to ensure uniform wall thickness of the product and consistent distribution of the conductive filler.
- Mold optimization and upgrade: Design a blow molding mold with uniform temperature and good sealing to ensure that the plastic is heated evenly during the molding process, providing a reliable guarantee for the stability of the resistance value.
As the source factory of the ESD plastic industry, INCHR has become a reliable partner in the industry with its rich experience accumulated over many years. We have overcome countless technical difficulties, whether it is the impact of complex molding processes on resistance values or various challenges in the production process, we have accumulated mature solutions. We not only provide customers with high-quality ESD plastic products but also have a complete after-sales service system. We look forward to working closely with our customers, deeply exploring every detail in production applications, jointly addressing and solving all problems and challenges encountered, and helping customers create greater value in their respective fields.
