As a kind of additive, modifier or filler, talcum powder is widely used in many chemical industries. It has obvious enhancement in the modified application of plastic and rubber. It can improve the tensile strength, impact property, creep resistance, heat resistance and tearing resistance of plastic products. It can also improve the appearance of products, reduce the shrinkage of products, improve the barrier effect, reduce the air permeability, increase the rigidity and of plastic products. It has become an important material to improve the physical properties of plastic products, and is becoming more and more popular in the plastic industry.
The raw material of talcum powder is talc. It has the advantages of high gloss, small oil absorption, good transparency, good chemical stability and excellent physical properties. The density is 2.7 ~ 2.8g/cm3, which is similar to the heavy calcium. The moth hardness is 1, which is the lowest in the inorganic powder. Because it is relatively soft in preparation, only simple mechanical friction is needed. But a special process is needed if a better surface activation modification is to be achieved.
So how to measure the good or bad of talcum powder?
(1) the higher the purity of pure talc, the better the enhancement effect. Other mineral impurities in talc and metallic minerals, especially iron, have a significant effect on the aging resistance of plastics.
(2) the color of the plastic will change more or less after mixing the wet whiteness and the hue talc and plastics. Dark plastic products do not have high requirements for the whiteness of the talcum added. However, in order to make the light color products have a better color, talc should have higher wet whiteness and suitable hue.
(3) the content of silicon (SiO2) in talc powder with SiO2 content is an important index to measure the grade of talcum powder. The talc powder should be selected according to the performance requirements of different plastic products. If the content of the talcum powder added in the film should be higher, the particle size is small and the size distribution is narrow, the high transmittance, tensile strength and puncture resistance of the film can be improved obviously. The requirement for silicon content in injection, plate and bar is not high. The talc powder with low silicon content is low in price and abundant in resources.
(4) during the extrusion process, the fluidity of talc is worse than other granular inorganic materials, and the dispersion is difficult and the torque of the screw is large. Therefore, the key to overcome the above problems is to use the better activator.
(5) the layered structure of the electrostatic talcum is larger than the surface area. The irregular shape of the particle and the convex concave shape of the surface make it have large friction coefficient and easy to produce static electricity. It causes the condensation between small particles, and it is difficult to disperse and influence the application effect.
Application field of plastics
Talcum powder can be widely used in PP, PE, PS, PA, ABS, PC, PVC and other resins. Talcum powder can reduce the production cost of plastic products, and also have the advantages of improving the rigidity, heat resistance, vermicular denaturation and reducing shrinkage of plastic products.
(1) film products talcum powder can also improve the mechanical properties of films, such as tensile strength, flexural strength and rigidity. It can also make the appearance of the film more colorful, pearl like, and feel improved.
(2) the fine talcum powder used in wire drawing products can obviously improve the physical properties of woven bags, and the use life and long-term safety of products are obviously improved. Satisfactory results can be obtained by adding proper amount of talcum powder to the production of round silk products. If 5% to 10% products are added to the wire of fishing net, it can effectively reduce the winding adhesion of the fishing net, and improve the visual effect of the fishing net in the fishing operation without affecting the transparent effect of the fishing net, and improve the fishing efficiency.
(3) the plastic bucket of hollow products in hollow products is a new type of packaging container. It has the advantages of chemical stability, small corrosion, light quality, clean sanitation and low production cost. It can replace the barrel produced by metal materials and is widely used in chemical, daily, oil, edible and medical supplies.
(4) there are many kinds of injection products, including industrial components, toy products, daily necessities, etc. The application of talcum powder in injection products can obviously improve the mechanical properties of injection products, reduce the sag caused by the gate and edge of injection parts, and improve the transparency, appearance effect and hand perception of the products. Talc also has excellent dielectric and barrier properties, reducing the magnetoelectric radiation effect.
(5) auto parts, aviation and military parts and parts talcum powder are the earliest and most used in automotive plastic parts. In aircraft, aviation, aerospace, military industry and other industries, the chemical resistance, high and low temperature stability and excellent mechanical properties of talcum powder have been recognized, and are widely used in military ammunition packing boxes. Medical boxes, mechanical ornaments and other products
(6) home appliance parts and components in China have developed rapidly in recent years. According to relevant information, 60% to 80% of household electrical appliances are made of plastic parts. Talcum powder can not only reduce the production cost of household electrical appliances, but also improve the quality and appearance of household appliances.
(7) the talc powder of pipe and plate products can improve the pressure resistance of the tube, especially the ring stiffness is an important index to restrict the large plastic pipe. After adding a certain amount of talcum powder, it can obviously improve the ring stiffness of the plastic pipe, improve the stability of the product size, and improve the rigidity, flame retardancy and chemical stability of the plate.