Primary Parameters for Electrostatic Measurement

Static dissipative materials are typically categorized by their resistivity. They are divided into conductive static (conductive) materials and dissipative static (dissipative) materials.

Early references to anti-static material categories:

Static Conductive Material

Electroconductive materials refer to those with conductive surfaces or internal structures. Static dissipative materials with surface resistivity less than or equal to 1 × 105 Ω/m² or volume resistivity less than or equal to 1 × 10^4 Ω·cm are classified as electroconductive materials. Among them, materials with surface resistivity less than 10^4 Ω/m² or volume resistivity less than or equal to 1 × 10^3 Ω·cm are defined as static shielding materials, meaning static shielding materials are a part of electroconductive materials.

2) Static Dissipation Material

Materials capable of rapidly dissipating static electric charges from their surface or within the object. The range of resistivity they possess varies according to different standards; however, many standards (such as the current MIL standards and the draft IEC standards issued in the past two years) specify that static dissipative materials have a surface resistivity greater than 1 × 105Ω / m² but less than or equal to 1 × 1012Ω / m², or a volume resistivity greater than 1 × 104Ω·cm but less than 1 × 1011Ω·cm.

3) Anti-static Materials

Certain standards, such as MIL-HDBK-263 from 1980, define anti-static materials as those with surface resistivity greater than 1 × 10^9 Ω/m² but less than or equal to 1 × 10^14 Ω/m². Many commonly used materials fall within this range, including melamine thin layers, high-resistance body conductive plastics, clean cotton, hardboard, wooden products, paper products, and more. The revised A version released in 1991 altered this classification method, no longer employing the concept of anti-static materials. During discussions on anti-static material standards by the International Electrotechnical Commission (IEC), experts generally favored the opinion that the concept of "anti-static materials" is too vague and should no longer be used.

4) Insulation Materials

Insulating materials refer to those with a resistivity exceeding the upper limit of electrostatic dissipation materials. They do not fall under the category of electrostatic protective materials. Due to their classification being closely linked with electrostatic dissipation materials, the relevant standards are not very consistent. The more and more authoritative current standards define materials with a surface resistivity greater than 1 × 10^12 Ω/m², or a volume resistivity greater than 1 × 10^11 Ω·cm, as insulating materials.