Haicheng talc is an important inorganic material for plastic modification. At present, it has been widely used in polypropylene modification at home abroad. It is mainly used to produce automobile parts, front rear bumpers, dashboard panels, interior decorative panels, etc .; In the home appliance industry, such as washing machine parts, air-conditioning parts, TV rear shells, electric heater shells various household appliances shells.
Talc is inexpensive is suitable as an extender. At the same time, the high flaky configuration aspect ratio (ratio of the average diameter of particles to its thickness) of talc makes it suitable as a reinforcing agent (improving the mechanical properties of the composite). Commercial talc for plastics is a finely pulverized product in a flake configuration.
Talc powder is widely used in plastics, its characteristics are as follows:
① Particle size shape Most talc products used as fillers are very fine. The crystal shape of talc can be flaky (layered), leafy (broad-leaved), needle-shaped, massive. Most of the talc particles produced in China have a flake structure. The ratio of the average diameter of flaky particles to their thickness is called the aspect ratio, it is an important index for measuring talc.
② Surface properties Talc shows different surface properties depending on its source. Product fineness affects specific surface area oil absorption. Other factors affecting these properties are surface roughness, particle shape, pore volume. In general, talc has a large specific surface area due to its flaky configuration.
③ Electrical thermal properties Talc is a non-conductor of electricity can be used to produce high-frequency electrical insulation materials. The talc is stable to a high temperature of 900 ° C. Talc has low thermal conductivity high thermal shock resistance. Under heating conditions, talc loses part of its structural water without changing its optical crystalline properties. When the temperature exceeds 800 ° C, talc loses its bound crystal water is decomposed into refractory by endothermic reaction.
④ Optical properties Pure talc has three refractive indices, X = 1.539, Y = 1.589, Z = 1.589. It has a small variable optical axis angle. Therefore, when talc is used in an agricultural greenhouse film, the direction of sunlight irradiation can be changed, direct light can be converted into scattered light, the thermal insulation effect of the film can be improved.
Introduction to fusion compound technology: Polymers filled with flaky talc exhibit higher stiffness creep resistance than polymers filled with particulate fillers (such as calcium carbonate) at room temperature high temperature. In order to maximize the above-mentioned properties, a special melt-composite technology is actually applied to incorporate a large amount of filled talc into the polymer. The special compounding of fine talc particles requires the application of all special melt compounding effects (rubbing, bending, stretching, smearing, pressing, shearing) so that the talc particles are fully wetted by the molten polymer the talc particles are highly dispersed , Thus forming a uniform composite material. For this reason, it is necessary to use a batch continuous melt-mixing device to produce filler-dispersed resin pellets. This filled premix can then be processed into the final product via injection, molding extrusion equipment.