The Static Electricity Conundrum Of Plastic Storage

Plastic is an excellent insulator, which means it is a poor conductor of electricity. As a result, electric charges tend to build up on plastics, leading to static electricity. This can be annoying, causing objects to stick together, and it can also be dangerous, as it may result in static shocks or even cause explosions. This is particularly relevant when using plastic storage, as the static charge can be trapped between the surfaces of the plastic and is difficult to remove. Understanding how to control and discharge static electricity safely is crucial to preventing potential hazards.

Plastic is an insulator

Plastic storage containers are a common source of static electricity. When rubbed against another material, such as a cloth, they can acquire a net electrostatic charge. This charge can be stored for hours or even days, and if it builds up sufficiently, it can result in a 'brush discharge'. This is when a spark is drawn from the surface of the plastic, which can be felt or heard as a click and sometimes seen as a faint flash of light in a dark room. These discharges can contain enough energy to ignite flammable vapours, causing fires and explosions in certain industries.

Certain types of plastics are excellent insulators, such as Mylar® and Melinex® polyethylene terephthalate (polyester PET) films, Teonex® and Kaladex® polyethylene naphthalate (polyester PEN) films, and VALOX™ flame retardant polybutylene terephthalate blend (PBT/PET/PC) films. Polyester films are often used for wire insulation due to their dielectric, mechanical, thermal, chemical-resistant, and moisture-resistant properties. They are also used in motors, batteries, and other electronics.

The effectiveness of plastic insulation depends on the type of plastic used, as different plastics have varying resistivity levels. In general, plastics with higher density are better at blocking electric current. Plastics such as polyvinyl chloride (PVC), polyethylene (PE), and cross-linked polyethylene (XLPE) are considered good insulators in electrical applications. They are commonly used as sheaths or jackets over wires and cables to prevent electrical shocks and reduce the spread of flames along cable paths.

Plastic is also used as insulation in pots and pan handles because it does not conduct heat or electricity, reducing the risk of burns when touched during cooking. Additionally, plastic resists corrosion from acidic ingredients, making it a practical choice for certain recipes.

Plastic can hold an electrostatic charge

The triboelectric effect, observed when rubbing two different materials together, such as a cloth and a plastic sheet, can cause plastic to acquire an electrostatic charge. This phenomenon is similar to what happens when your socks become electrostatically charged after being in the dryer. The frictional contact between the two materials results in a transfer of charge, leaving one material with an excess of positive or negative charges.

In a dark room, you may see faint flashes of light or hear a crackling sound when rubbing certain plastics, indicating the presence of static electricity. Additionally, if you approach the charged plastic surface with your finger, you may experience a "brush discharge" as a small spark.

The accumulation of static electricity on plastic can have several implications. For example, in film manufacturing, static charge can cause sheets of film to stick together. It can also attract dust and, in extreme cases, lead to explosions. In electronic assembly, static electricity can damage sensitive electronic components.

To mitigate the buildup of static electricity on plastic, various techniques and materials can be employed. Anti-static materials contain additives that attract water molecules to the surface, preventing a static charge from accumulating. Static dissipative materials, while expensive, can effectively dissipate static charges but require proper grounding. Conductive materials provide another option for controlling static electricity.

Plastic can cause static shocks

Plastic is an excellent insulator, which means it is a poor conductor of electricity. This is why plastic items can hold a static charge. When a plastic item leaves the mold, it holds a high static charge level. If you rub a plastic item with a cloth, it will almost certainly acquire a net electrostatic charge. This is why shuffling your feet on a carpet and then touching a plastic item can result in a static shock.

Static electricity can be annoying, as it causes objects to stick together, especially inside a plastic box. It can also have serious consequences in process safety if it is not properly understood and controlled. For example, plastic containers and other plastic items can accumulate and hold electrostatic charge for hours or days. If they hold enough charge, ''brush discharges' can be drawn from the surface. These discharges can have enough energy to ignite common solvent vapors used by the chemical and pharmaceutical industries and in many other industries where flammable liquids and gases are handled or processed.

There are several ways to prevent and eliminate static electricity on plastic items and surfaces. One simple method is to rub a dryer sheet along the inside and outside of the plastic item or surface. Dryer sheets contain external anti-static agents that can make a plastic item or surface more conductive. Objects with high conductivity cannot retain static, so rubbing a dryer sheet on a plastic item or surface will help to dissipate static. Another option is to moisten the plastic item or surface slightly, using a wet paper towel, or by spraying it with an anti-static spray. Anti-static sprays coat objects with a thin layer of conductivity "skin" that prevents static from clinging to an object.

In industrial settings, it is especially important to control static electricity to prevent fires and explosions. In these cases, it may be necessary to use materials that are described as having anti-stat additives or as being statically dissipative or conductive. For example, a tray used to hold sensitive electronics made of statically dissipative materials will help to dissipate any static charge from a worker so that it does not damage the electronics.

Plastic attracts dust and particles

Plastic is an insulator, and as such, it can accumulate and hold an electrostatic charge. When a plastic part leaves the mould, it holds a very high static charge level. This charge attracts airborne dust and particles, which immediately stick to the plastic, contaminating it. This is a common issue for products made from plastic, such as TV screens, which are difficult to keep dust-free.

The problem of dust and particle attraction is not limited to plastic, but also affects other insulators, such as glass, PC-board laminate, protective films, and foils. These materials are often used in optics and electronics, and the build-up of dust and particles can cause processing problems and quality issues. For example, the static charging of plastic packaging can cause coffee to stick to the plastic, leading to leaks and customer complaints.

The static charge on plastic can be removed using ionizing or blowing ionizing equipment, which eliminates the electrostatic attractive forces and allows for the straightforward removal of dust and particles. In some cases, it is necessary to prevent a charge build-up on moving conveyor belts by using antistatic bars or fans. When handling plastic parts with high static charge levels, operators can receive static shocks, and customers may complain about static when separating or handling the parts.

To eliminate static shocks to operators and dust attraction, StaticString™ or Ion360™ Rods can be placed so that the plastic parts pass through them, removing the high static on their surface. This is particularly important in industries where flammable liquids and gases are handled or processed, as electrostatic discharges from plastic surfaces can have enough energy to ignite common solvent vapours.

Anti-static sprays can prevent static

Plastic is an insulating material that can accumulate and hold electrostatic charges for hours or even days. This can cause several issues, such as attracting dust and particles, causing static shocks, and even leading to brush discharges that can ignite flammable vapors.

To prevent these issues, anti-static sprays can be used. These sprays neutralize static electricity generated by friction and low humidity conditions. They leave a light coating on the surface that eliminates static charges and prevents further accumulation. Additionally, they can help repel lint and dust, keeping the surface clean.

One such product is the Sprayon SP610 Anti-Static Spray, which is effective on various materials, including plastic, paper, rubber, and cloth. It is commonly used in industries where static electricity can pose a safety hazard, such as the chemical and pharmaceutical industries.

By using anti-static sprays, operators can handle plastic parts without experiencing static shocks. It also helps to prevent the contamination of plastic surfaces by reducing the attraction of dust and particles. This is particularly important in industries where clean surfaces are crucial, such as food processing or electronics manufacturing.

In addition to anti-static sprays, other methods can be employed to control static electricity on plastic surfaces. For example, in manufacturing processes, robotic arms can be equipped with StaticString or Ion360 Rods to remove static from plastic parts as they are transported. This ensures that the static is eliminated before the parts are stacked or packaged, reducing the chances of static-related issues down the line.

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