What is the difference between anti-static, dissipative, conductive and insulating
Static electricity
As the name suggests, static electricity is static electricity. Charge is the transfer of electrons that occurs when a material slides, rubs, or separates. The material is a generator of electrostatic voltage. For example: plastic, glass fiber, rubber, textile, etc. Under proper conditions, this induced charge can reach 30,000 to 40,000 volts.
When this happens on insulating materials (such as plastic), the charge tends to remain in the local area of contact. When plastic materials come into contact with the human body at sufficiently different potentials (such as people or microcircuits), the electrostatic voltage may be discharged through arcs or sparks.
If a person experiences an electrostatic discharge (ESD), the results can range from mild to painful electric shocks. Extreme situations of ESD or arc flash can even lead to loss of life. Such sparks are particularly dangerous in environments that may contain flammable liquids, solids, or gases (such as hospital operating rooms or explosive device components).
ESD as low as 20 V may damage some microelectronic parts. Since people are the main cause of ESD, they usually damage sensitive electronic parts, especially during manufacturing and assembly. The consequences of discharging ESD-sensitive electrical components can range from erroneous readings to permanent damage, resulting in excessive equipment downtime and expensive repair or total parts replacement costs.
Electrostatic discharge (ESD)
Sudden current flow between two charged objects due to contact, short circuit, or dielectric breakdown. Friction or electrostatic induction may cause static electricity to accumulate.
anti-static
Prevent the accumulation of static electricity. By retaining enough moisture to provide conductivity, reduce static charges on textiles, waxes, polishes, etc.
dissipation
Compared with conductive materials, the charge flow to the ground is slower and the degree of control is stronger. The dissipative material has a surface resistivity equal to or greater than 1×10 5 Ω/□ but less than 1×10 12 Ω/□ or a volume resistivity equal to or greater than 1×10 4 Ω-cm but less than 1×10 11 cm 2
Conductivity
Due to the low resistance, electrons easily flow across the entire surface or most of these materials. Another conductive object that will be grounded or in contact with or near the material. The conductive material has a surface resistivity greater than 1×10 less than 5 Ω/square or a volume resistivity lower than 1×10 4 Ω-cm.
Insulation
The insulating material prevents or restricts the flow of electrons through its surface or through its volume. The insulating material has high resistance and is difficult to ground. The static charge on these materials will remain for a long time. Insulating materials are defined as those having a surface resistivity of at least 1×10 of 12 Ω/□ or a volume resistivity of at least 1×10 of 11 Ω-cm.
Anti-static material category
Materials used to protect and prevent electrostatic discharge (ESD) can be divided into three different groups-separated by their conductivity and range of charge.
anti-static
The resistivity is usually between 10 9 and 10 12 ohms per square. The initial static charge is suppressed. It may be surface resistive, surface-coated or completely filled.
Static dissipation
The resistivity is usually between 106 and 109 ohms per square. Low or no initial charge-to prevent the human body from contacting and discharging. It can be surface coating or whole filling.
Conductivity
The resistivity is usually between 103 and 106 ohms per square. There is no initial charge, which provides a way for charge loss. Usually, carbon particles or carbon fibers are filled.
Resistivity test method
Surface resistivity
Surface resistivity measurement For thermoplastic materials that intend to dissipate static charges, surface resistivity is the most common indicator of the material's antistatic ability.
The widely accepted surface resistivity test method is ASTM D257. It involves measuring the resistance (via an ohmmeter) between two electrodes applied to the surface under load. Due to the heterogeneous composition of composite thermoplastics, electrodes are used instead of point probes. It may not be possible to obtain a reading consistent with the entire part by merely touching the surface by point contact (even if the part is actually conductive, this reading is often insulated).
It is also important to maintain good contact between the sample and the electrode, which may require considerable pressure. The resistance reading is then converted to resistivity to account for the size of the electrode, which can vary depending on the size and shape of the test sample. The surface resistivity is equal to the resistance multiplied by the electrode circumference divided by the gap distance to get ohms/square.
Volume resistivity
Measuring volume resistivity Volume resistivity can be used to evaluate the relative dispersion of conductive additives throughout the polymer matrix. It may be roughly related to the EMI/RFI shielding effect in certain conductive fillers.
The volume resistivity is tested in a manner similar to the surface resistivity, but the electrodes are placed on the opposite side of the test sample. ASTM D257 also deals with volume resistivity, and again a conversion factor based on electrode size and part thickness is used to obtain resistivity values from resistance readings. [Volume resistivity is equal to resistance multiplied by surface area (cm 2) divided by the thickness of the portion (cm) that produces ohm-cm. ]