To use talcum powder in plastics, clear keep these 9 criteria in mind!
Talc is one of the most widely used inorganic powders in plastic products. Talcum powder in plastic products is characterized by certain properties that can significantly improve the plastic products, therefore, the choice of talcum powder should also have the following requirements for talcum powder.
High purity
The higher the purity of talcum powder, the better its enhanced effect. Talc in the other mineral impurities, metal minerals (especially iron) has a very obvious effect on the aging resistance of plastics.
Structure
Talc is usually a dense block, blade, radial, fibrous aggregates. Because the crystallization structure of talc is layered, so it has the tendency to split into scales and special lubricity.
High-quality ultra-fine talc into a lamellar structure, used in plastic products, can be uniformly dispersed in the resin in the lamellar form, and the resin has a better compatibility and mechanical properties of the complementary.
Like the metal structure network embedded in cement products, it can form the reinforced support form with excellent mechanical properties in addition to maintaining the advantages of plastics, which can improve the physical properties of plastic products, and it also has obvious thermal insulation and barrier effect, which can improve the physical properties of plastic products while reducing the production cost.
Wet whiteness and color
Talc and plastic mixing makes the color of plastic change more or less. Dark-colored plastic products do not have high requirements for the whiteness of the talc added. But in order to make light-colored products have better color, talc should have higher wet whiteness and suitable color phase.
Silicon dioxide content
Silicon (SiO2) content in talcum powder is an important index to measure the grade of talcum powder, the higher the silicon content in talcum powder, the higher the purity of talcum powder, the better the application effect and the higher the price.
Customers need to choose talc according to the performance requirements of different plastic products, such as agricultural films in the addition of talcum powder silicon content should be higher, small particle size, particle size distribution is narrow, in order to make the film's light transmittance is good, the film's tensile strength, resistance to puncture and other indicators have to improve.
And in the injection molding, plates, rods in the use of talc, silicon content requirements do not have to be too high, silicon composition of the product is not only lower price, but also improve the hardness of plastic products, impact strength, and so on.
Color
The color of unprocessed talcum powder ore is different from each other, can be white, gray, light red, pink, light blue, light green and other colors, talcum powder also has a special kind of silver-like or pearl-like color, and has a different degree of solid luster. This color can improve the appearance and visual effect of the products.
Surface properties
Talcum powder has different surface properties depending on its source. Specific surface area and oil absorption are largely determined by mineral resources and product fineness. Other factors affecting these properties are surface roughness, particle shape, and pore volume. Talc's larger specific surface area and appearance and structure affect the amount of additives used, while also promoting bonding between resin structures, thus improving the physical properties of plastic products.
Moisture
The structural form of talc determines its properties, although talc is hydrophobic, but due to the irregularity of the edge of its particle shape, there is both structural water and water of crystallization, so the moisture of talc is larger than calcium carbonate, and the moisture is very easy to affect the performance of plastics, so the removal of moisture and drying treatment process of talc should be given great attention.
Static electricity
Talcum powder is layered structure, large specific surface area, irregularity of particle shape and the surface of the convex-concave pattern makes it friction factor, easy to generate static electricity, resulting in the cohesion between the tiny particles is difficult to disperse, affecting the application effect.
Fluidity
In the extrusion process, the lamellar structure of talcum powder has poorer fluidity than other granular inorganic materials, and it is difficult to be dispersed, and the torque of the host screw is large, so better activation of the coating is the key to overcome these problems.
