Yuan Lei's Little Knowledge | Application Characteristics and Requirements of Talcum Powder in Plastics
1. Application characteristics of talcum powder in plastics
(1) Talc has a layered structure, and the adjacent two layers are combined by weak van der Waals force. Under the action of external force, the adjacent two layers are extremely easy to slip or separate from each other. Therefore, talcum powder in plastic processing, under the action of friction and extrusion of mechanical equipment, talcum powder particles are easily peeled off layer by layer, thus forming a new particle structure and agglomeration, although through coupling agent or other chemical surface treatment technology, but to achieve better surface activation modification effect, still need to take special process.
(2) The remarkable reinforcing effect of talc on plastic products mainly comes from its unique micro-sheet structure. The more complete the flake structure of the processed talc powder is maintained, the more obvious the enhancement effect is. Larger diameter to thickness ratio can improve the rigidity, impact strength, flexural modulus and thermal stability of plastic products.
(3) High-quality ultra-fine talc powder into a flake structure, when used in plastic products, can be evenly dispersed in the resin into a laminated form. As cement products embedded in the metal structure of the network, to maintain the advantages of plastic itself, the formation of excellent mechanical properties of the enhanced support form, can improve the physical properties of plastic products, but also has obvious insulation, barrier effect.
(4) The pH value of talc is 9.0~9.5, the chemical stability is good, and it is resistant to weak acid, alkali and salt.
(5) The color of talc is white, gray green, milk white, light red, light blue, light gray, etc., and some have pearl or fat luster. Talc powder for plastics often hopes that the higher the whiteness, the better. When crushed, various talc becomes a powder from gray to white, and presents different degrees of solid luster, but after application in plastic products, Trace changes in color will occur.
(6) talc and mica, kaolin and other silicon containing minerals have infrared and ultraviolet barrier properties, in plastic products with obvious insulation, aging resistance and other effects.
(7) The smooth feeling of talc is very obvious, and the plastic opening of talc powder is obviously improved, and the anti-blocking property of the film can also be improved.
(8) When ultra-fine talc powder is uniformly dispersed in the plastic matrix, it can act as a nucleating agent.
2. Application requirements of talcum powder in plastics
SiO2 content: The silicon content in talc is an important indicator to measure the grade of talc. According to the performance requirements of different plastic products to choose talcum powder, such as in the film added talcum powder silicon content should be higher, small particle size, narrow particle size distribution, in order to make the film high light transmittance, tensile strength, puncture resistance and other indicators have been significantly improved.
Fluidity: In the extrusion process, talc has poorer fluidity than other granular inorganic materials, is difficult to disperse, and has a large screw torque. Therefore, the use of better activation additives is the key to overcome the above problems.
Electrostatic: talc has a layered structure with a large specific surface area. The irregularity of particle shape and the convex and concave shape of the surface make its friction coefficient large and easy to generate static electricity, resulting in condensation between tiny particles, which is difficult to disperse and affects the application effect. Static storage to eliminate static technology, both simple and practical, and easy to operate. In other inorganic powder can also refer to this process.
3. Application of talcum powder in plastics
Talc powder can be widely used in PP, PVC and other resins. Talc powder not only reduces the production cost of plastic products, but also has the advantages of significantly improving the rigidity, heat resistance, creep resistance and reducing shrinkage of plastic products.
Talcum powder is widely used in automobile bumpers, instrument panel trim, interior trim panels, pipes, heat insulation panels and plastic parts, etc., which can improve the impact strength of plastic products, improve the creep resistance at high temperatures, and reduce shrinkage. Rate, give the parts a better surface quality, a more gorgeous appearance, and a more suitable touch.
The application of talcum powder in injection molding products can significantly improve the mechanical properties of injection molding products, reduce the depression caused by the shrinkage of the gate and edge of injection molding parts, and improve the appearance effect and feel.
Talc powder can also improve the quality and appearance of home appliances, especially in aging resistance, sun protection, fading, heat insulation, heat preservation, flame retardant, sound insulation and improve product special functions, has irreplaceable advantages and characteristics.
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