Seevent Plastics Ltd are the only UK based supplier of VCI (Volatile Corrosive Inhibitor) products, extruding and converting film from our custom manufacturing facility in Reading.
Before VCI almost all metal products, it left unprotected, would oxidise and deteriorate when moisture in the air and oxygen combined, leading to rust, tarnishing and corrosion. Traditionally, to protect the components, the parts were covered with oil/grease or with paper impregnated alternatives, however they often needed additional packaging and cleaning before they could be used. Pro-Corr film uses an established VCI masterbatch that is extruded right into the polyethylene so that the active inhibitors provide long term protection. The VCI agent works by releasing an invisible, odourless and non-toxic corrosion inhibiting vapour into the air. The vapour molecules settle on the metal parts forming a microscopic protection film that prevents corrosion. On opening the bag, the VCI protective layer evaporates leaving the product clean, dry, corrosion free and ready for use.
As electronic circuits continue to shrink in size so their susceptibility to damage from static electricity has increased. A shrinkage factor of 10 in feature size makes gate oxides 10 times more sensitive to ESD’s. Protective handling and packaging techniques have been adapted by all segments of the electronics industry to meet this challenge.
Sensitive electronic circuits can be destroyed with just a 30 volt differential, however the human body can easily generate a charge in excess of 5,000 volts from just a minimal movement. It is therefore vital that insulators such as standard poly bags and not effective.
There are three primary static threats:
Direct Discharge (ESD): A discharge directly to a bag can subject the device inside to very high voltage which results in melting or fusing of the circuit
Static Fields: Fields can induce destructive currents in circuit conductors which can break down circuit dielectric
Tribocharging: Friction between the bag and device can produce damaging static voltage and fields
The three variants are defined by measuring the surface resistivity of the film in Omhs (per square) using the ASTM D-257 test method, we measure and adhere to these standards and produce three distinct grades for the market.
Semi-Permanent (Low charge): suited best to secondary applications in Static Control Areas or Electrostatic Protected Areas or can be used for intimate packaging. These work by absorbing moisture from the air to make the surface slightly conductive and our film meets EN 100.015/1 and military spec B-81705 (type II) with a surface resistance 10¹0- 10¹²Ω.
Permanent or Dissipative: These use a matric style masterbatch that is slightly conductive across the film and is used where an Electrostatic Discharge (ESD) from human contact must be prevented. This type of treatment is unaffected by relative humidity and has a long active life with a surface resistance in the range of 10/6 – 10/8Ω
Black Volume Conductive: Using carbon loaded masterbatch and always in opaque black, once sealed gives ‘Faraday Cage’ style protection to sensitive electronic components. The film is unaffected by moisture and has a very long shelf life with a surface resistance in the range of 10/4 – 10/6Ω