In industrial production, the use of plastic additives is essential. They help make products more durable, aesthetically appealing, and highly functional. So, what role do plastic additives play in the plastic processing industry? Let’s explore this in the following article.
What are plastic additives?
Plastic additives are either simple or compound chemicals. They can be inorganic, organic, or synthetically derived from natural sources. These additives are mixed with plastic to alter or enhance certain properties of the plastic, such as color, flexibility, brittleness, and more. Depending on the product’s purpose, manufacturers will blend plastic pellets with the appropriate additives.
Uses of plastic additives
Often, when people hear the term “additives,” they may be hesitant, thinking they are harmful. However, plastic additives actually serve many beneficial purposes for plastic products. Pure plastic lacks the necessary durability, flexibility, and rigidity, which is why additives are essential. Different types of additives offer superior properties compared to pure plastic.
- Slip additives
Slip additives used in the plastic industry are categorized into two types:
- Internal slip agents: These reduce friction between the polymer chains or segments, preventing the plastic from melting under heat.
- External lubricants: These prevent sticking between the plastic and surfaces such as cylinder walls or screw shafts. They also prevent the plastic from adhering to molds during the molding process.
Manufacturers typically use chemical compounds such as fatty alcohols, fatty acids, paraffin, metal soaps, and low molecular weight polyethylenes to create slip additives.
- Optical brighteners
Optical brighteners (also known as optical whiteners) belong to the family of fluorescent chemicals. They absorb ultraviolet light and emit blue light. This emission helps make products appear more radiant and fresh. The emitted blue light also masks the red-orange wavelengths, making the product appear whiter. These additives are commonly referred to as whitening agents or super whiteners.
- Stabilizing additives
Stabilizing additives help preserve and protect the final products. Currently, two types of stabilizers are used to increase the stability of plastic:
- UV stabilizers (anti-UV additives): These protect plastic from damage caused by exposure to sunlight over long periods by using substances like hydroxybenzoic acid, ester of acrylic acid, hydroxyphenyl compounds, and benztriazoles.
- Thermal stabilizers: Primarily used for rigid and flexible PVC, they ensure the plastic remains stable and does not decompose during processing at high temperatures. Organic compounds like salts, calcium, cadmium, and zinc are typically used for this purpose.
- Antistatic additives
Antistatic additives are made from antistatic agents that reduce static charge accumulation on the surface of plastic products. This makes the production process safer and more efficient, while also minimizing dust buildup on products during display or storage.
- Antioxidant additives
Although it may seem counterintuitive, plastic products also require antioxidants. These additives expand the temperature range for plastic and increase its lifespan. They slow down the reaction processes caused by oxygen or peroxides, thereby extending the product’s usability.
- Foaming additives
In addition to additives that enhance flexibility, foaming additives are also important. They help create small holes or air pockets in the product, making it lighter in weight and more material-efficient while maintaining quality. These additives improve thermal insulation, soundproofing, and the overall durability of plastic, while reducing shrinkage or deformation on the plastic surface.
- Flame retardant additives
Flame retardant additives reduce the flammability of plastic products. They work by preventing oxygen on the plastic’s surface from coming into contact with flames or heat, often by forming a protective surface layer.
- Deodorizing additives
Deodorizing additives are not essential for every plastic product, but they are commonly used in products related to health or recycling. Items like toys, plastic bags, cups, bottles, and straws may require deodorizing additives to remove undesirable odors.