Various applications of additives in the plastics processing industry

Some plastics are simply resins, such as polyethylene, polystyrene, etc. They are called single-component plastics. In addition to synthetic resins, some plastics also contain other auxiliary materials, such as plasticizers, stabilizers, colorants, various fillers, etc., known as multi-component plastics.

stabilizer

We all know that in the process of processing, storage and use of plastic products, under the action of light, heat and oxygen, aging, fading, embrittlement and cracking will occur. In order to delay and prevent the occurrence of aging, stabilizers must be added. Mainly used to prevent heat aging, called heat stabilizers; mainly used to prevent oxidation aging, called antioxidants; mainly used to prevent photoaging, called light stabilizers, they are collectively referred to as stabilizers. Today's most outstanding plastic stabilizer is Methyl Tin Heat Stabilizer (abbreviated as 181), which is very effective for calendering, extrusion, injection molding and blow molding of rigid polyethylene (PVC). Because of its high safety, it is especially used for food packaging and high-definition rigid polyethylene products. At the same time, it is also commonly used in plastic doors and windows, water pipes, and decorative materials to replace other highly toxic plastics. Heat stabilizers. It has been widely used in the United States, Europe and Japan. In recent years, 181 Methyl Tin Heat Stabilizer has begun to be used in large quantities in China.

Plastic additives

Plastic auxiliaries The purpose of adding auxiliaries in plastics is mainly to improve the processing performance, increase the use efficiency and reduce the cost. Auxiliaries have a smaller proportion in plastic materials, but they have a great influence on the quality of plastic products. Different kinds of plastics have different types and amounts of additives because of different molding processing methods and using conditions. The main additives are the following types:

Plasticizer

Plasticizers can increase the flexibility, extensibility, and plasticity of plastics, reduce the flow temperature and hardness of plastics, and facilitate plastic molding. Commonly used phthalates, sebacates, chlorinated paraffins, etc.

Flame retardant

Auxiliaries that increase the flame resistance of plastics are called flame retardants. Most plastics containing flame retardants have self-extinguishing properties, or slower burning rates. Commonly used flame retardants are yttrium oxide and aluminum, boron compounds, halides and phosphates, tetrachlorophtalic anhydride, tetra-phthalic anhydride and so on.

Lubricant

Lubricants are substances that are added to improve the mold release properties of plastics during hot forming and improve the surface finish of products. Commonly used lubricants are: stearic acid and its salts, paraffin, synthetic wax and so on.

Reinforcements and fillers

In many plastics, reinforcing materials and fillers occupy a considerable proportion, especially reinforced plastics and calcium plastic materials. The main purpose is: In order to improve the strength and rigidity of plastic products, various fiber materials or inorganic materials are generally added. The most commonly used reinforcing materials are: glass fibers, asbestos, quartz, carbon black, silicates, calcium carbonate, metal oxides, and the like.

Antistatic agent

Antistatic agents act to eliminate or reduce static electricity on the surface of plastic products. Most of the antistatic agents are electrolytes, and their compatibility with synthetic resins is limited, so that they can migrate to the plastic surface to absorb moisture and eliminate static electricity.

Foaming agent

A plastic foaming agent is a low-molecular organic substance that can be gasified at a certain temperature, such as dichlorodifluoromethane, or an organic compound that decomposes gas when heated. These gases remain in the plastic matrix to form a foam with many fine foam structures. Commonly used azo compounds, nitroso compounds and so on.

Colorant

Colorants are used for coloring plastics. Mainly from landscaping and modification. About 80% of plastic products are colored into finished products.