What Is Plastic Compounding?

Composite plastic is a general term for plastics made of hard plastic and soft plastic, solid plastic and foam plastic.

To trace the history of composite materials, it is necessary to cross the human birth period about 2 million years ago, and explore the primitive biological era hundreds of millions of years ago. Taking shells as an example, shells are a composite of calcium carbonate and a certain protein. Among them, calcium carbonate can be strictly divided into two kinds of materials with different crystal structures, calcite type (oyster shell, etc.) and aragonite type (clam shell, etc.). In addition, its remains become

Filler composite plastics are conventionally classified according to the type of plastic and filler, as shown in Figure 1. Because the types of plastics are thermoplastic and thermosetting, the manufacturing methods of composite plastics are very different. Thermoplastic composites are usually mixed with resins and fillers and then melt-kneaded into granules, and then go through a molding process. Generally, the manufacturing method of the thermosetting composite plastic is to impregnate the resin raw material in the filler or

There are two factors hindering past development:

The great development of thermoplastics, since the 1930s, new types of thermoplastics have been industrialized one after the other, and they have developed by leaps and bounds in unprecedented numbers. At this time, both manufacturers and users are focusing on pursuing the maximum number of plastics. Less attention is paid to its compounding with other materials.

Composite technology and related technologies are immature. It is necessary to look at the combination of composite engineering and molding methods. It is relatively easy to add a large amount of fillers and other additives to rubber and thermosetting plastics, but for thermoplastics, it is technically limited to compound fillers on the premise of high productivity. At the same time, thermoplastics mainly use high-speed molding methods such as injection molding and extrusion molding, which is also a disadvantage for composite plastics. Especially for injection molding, there are great disadvantages such as reduced fluidity and poor product appearance. In addition, the quality of the composites fluctuates greatly. Originally, the composites were compounded to improve quality and expand use, which caused problems in quality reliability. ^[1]

Fire resistance. The revision of the US UL standard for household appliance components has generally proceeded according to the original schedule, and Phase II has been completed. Correspondingly, various flame-resistant plastics are being gradually developed. In addition to the flame-resistant plastics of the antimony trioxide-organic halide system, flame-resistant plastics containing aqueous inorganic compound systems such as aluminum hydroxide and magnesium hydroxide have also been developed. Composite plastics have become the mainstream of flame-resistant plastics.

Environmental issues. Corresponding technical requirements for automobile exhaust management countermeasures are: As the combustion temperature in the engine rises, the heat resistance of the relevant materials of the engine must increase. As the weight of the engine increases, the weight of the relevant materials must be reduced. Among the materials that can meet the above two requirements, expectations for composite plastics are increasing, and various components are being actively replaced with composite plastics.

Food hygiene issues. The composite materials of polyolefin and inorganic fillers do not have the problem of residual monomers, and they are easy to burn. Therefore, they began to attract attention and considered development. Later, through technical research, their advantages such as extrusion moldability, vacuum moldability, product rigidity and impact resistance It is becoming more and more obvious that it has occupied a large position as a material for food containers such as dairy products.

Resource issues. Resource issues include two aspects, one is to save plastics that use petroleum as raw material, and the other is to reduce the weight of the car body and the body to save fuel. Either aspect is indeed an increasingly important issue in the future. In terms of saving raw materials, composite plastics using various inorganic fillers are obtained from inorganic resources and do not rely on petroleum. They are much smaller than metals in terms of specific gravity. With these advantages, they can be called materials suitable for the times. .

Social issues. A key issue in energy development and space development is the high heat resistance and specific strength requirements of materials. Various methods have been used to improve these properties of plastics. One of them is the invention of a material called "advanced composite", which is a combination of inorganic fibers and metal whiskers with high heat resistance and specific strength. The composite material made of crystals has reached the practical application stage. In addition to the matrix polymer, thermosetting plastics such as epoxy resin and polyimide are used, and heat-resistant thermoplastics such as polyphenylene sulfide are also being studied and tested.

Residential development. FRP is extremely popular in bathtubs, sinks, toilets and drying platforms, and will continue to occupy a high position in the future.

Diversity of life. People are becoming more interested in functional materials, and they are actively researching so-called functional polymers that enable polymers to have multiple functions. Some of the research results have been applied in practice. On the other hand, an idea has begun to appear that it can have a variety of functions, and can meet the requirements in terms of price and other properties (formability and strength, etc.). Perhaps it is a composite plastic with functional fillers dispersed. As a new field, this kind of composite plastic will be seriously studied in the future.

Price trends. In the new situation after the oil crisis, future price trends due to raw material issues are also developing in a favorable direction for composite materials. ^[1]