Application of inorganic powder in plastics

Plastic is everywhere in life, and powder is everywhere in plastic.

Powder materials for plastics include inorganic powders and carbon-containing powders.

Inorganic powder is divided into industrial waste residue and non-mineral powder. Industrial wastes include red mud, white mud, fly ash beads (glass beads), etc.; non-mineral powders are divided into heavy calcium, talc, kaolin, wollastonite, mica powder, brucite powder, which are crushed and classified , Barite powder, etc., light calcium (including nano-calcium carbonate), aluminum hydroxide, magnesium hydroxide, precipitated barium sulfate, etc. formed by chemical reaction.

Carbon-containing powder is divided into carbon and carbon oxide powder. Carbon includes carbon black, graphite, etc.; carbon oxide powder includes wood powder, straw powder, nutshell powder, starch, etc.

The role of traditional inorganic powder in plastics

• The modification effect of calcium carbonate on plastics

Mechanical properties: improve the rigidity and hardness of plastic products, improve tensile and flexural strength, and significantly increase the modulus of elasticity; thermal properties: the coefficient of thermal expansion and shrinkage are reduced in all aspects, and the warpage and curvature of the product become smaller. The deformation temperature increases with the increase of the filler, and the radiation performance: the filler has a certain absorption capacity for radiation, which can prevent the aging of plastic products.

• The modification effect of wollastonite on plastics

It has good insulation, wear resistance, and high refractive index; it can improve impact strength, enhance fluidity, and improve tensile strength and mold shrinkage; it can significantly reduce the water absorption of the material.

• Modification effect of talcum powder on plastics

It can improve the tensile strength, impact performance, creep resistance, heat resistance, tear resistance of plastic products, improve the surface appearance of the product, reduce the shrinkage of the product, improve the barrier effect, reduce the air permeability, and increase the rigidity of the plastic product And crispness.

In addition to the above inorganic powder fillers, steel sulfate can improve the chemical resistance, heat resistance, and appearance of plastic products. Mica powder can reduce the shrinkage, warpage, curvature and specific gravity of the product, and improve the product. The mechanical properties of the product increase the surface gloss and weather resistance of the product.

Comparison of application performance of different inorganic powders in plastics

Performance comparison of different materials filled in nylon 66

Comparison of properties of polypropylene filled with different materials

Several factors affecting the application of inorganic powder in plastics

• Surface modification and activation of inorganic powder

The compatibility of inorganic powder fillers with polymers is relatively poor. If added directly, inorganic powders cannot be uniformly dispersed in the polymer, and its surface modification and activation are very important. Activation rate + fastness = modification effect.

• Moisture and volatile matter in inorganic fractions

Moisture and volatile matter will form gas due to high temperature, friction and other factors during plastic processing. After cooling, it will cause irregular cracks in plastic products, and may also cause secondary agglomeration of dried fine powder. In actual production and application, when the moisture and volatile matter are at 20.3%, it will affect the plastic processing and product quality.

• Static electricity

Inorganic powder with flaky structure is easy to rub and generate static electricity in the middle of processing, which makes small particles agglomerate and affects the dispersion effect of the product.

What are the new applications of inorganic powders

• Kaolin

Improve the tensile strength and modulus of low-plasticity plastics with a lower glass transition temperature; refer to the rigidity and strength of high products; increase the electrical insulation strength of the plastic after burning, and be used for high-voltage insulation products.

• Wood flour, bamboo flour, straw flour

Rich sources, low prices, low-carbon and environmentally friendly; heat resistance is the main bottle precondition that restricts dosage and use.

• Fly ash

The specific gravity is small, the hardness is large, and the fluidity is good; the fly ash is processed into a new material with a certain particle size and has adsorption performance, which can effectively adsorb harmful substances, odors and moisture.

• Calcium silicate

Small specific gravity, strong odor adsorption, excellent physical properties; mainly used in waste plastic processing, plates, pipes, etc.

• Electric lime

The main discharge of chemical products is solid waste; it is mainly used in plastic materials.

• Black talc, black calcite

It can partially replace carbon black.

Six major trends in the development of inorganic powders

Harmless production and application, industrial extension, miniaturization of processing and application, scientific value, diversification of application, and high-performance products.

Inorganic powder is a new functional modified material with abundant resources, low price and excellent performance. However, we should strive to abandon the traditional cognition that inorganic powder is a low-value filler material. Significant technological breakthroughs should be made in low carbon and other aspects. Inorganic powders should develop in the direction of functionalization, greening, and miniaturization, so that low-value-added filler materials will be fully transformed into high-end functional modified materials.

Article source: China Powder Network