Talc
Talc is a kind of hydrated magnesium silicate found in nature as metamorphosed rocks. Micronized powder of this mineral is used in the paint industry.Talc consumes as a Filler, in rubber industry (filler, paper industry filling and leveling) and ceramic industries (sound elasticity high permeability and cost-effective coefficient), cosmetic industry, ink baby powder, textile and also in medicine.Softness, good permeability coefficient, neutrality against solution and specific weight are the main qualities of talc in paint industry, which have caused it to rival titan dioxide.Talc is practically insoluble in water and in alkalis and weak acids. It is the the world's softest mineral and neither explosive nor flammable. Although it has very little chemical reactivity with a marked affinity for certain organic chemicals, i.e. it is organophilic. More than 900°C, talc progressively loses its hydroxyl groups and above 1050°C, it re-crystallizes into different shape of enstatite (anhydrous magnesium silicate). Talc's melting point is at 1500°C.
Applications
Rubber industry is normally using Talc due to its mechanical and physical properties.
Talc is used as a lubricant because of its smooth surface. When it’s used between two layers in rubber production, it avoids stickiness and friction.
Talc powder makes a very good reinforcing performance in rubber and it increase the tensile and tear strength as well as dimensional stability of final product as a result. Moreover, due to its excellent adsorption and affinity, it’s able to improve the fluidity in processing.
Due to its excellent thermal stability, high reinforcement, convenient addition, small amount of addition, high thermal decomposition resistance, good dispersion and anti-ultraviolet characteristics, it has variety of applications in rubber products such as cables, tires, hoses and gloves, rubber threads, etc.
Talc is hydrophobic and opaque is nature, so that will help to improve the water repulsion and water resistant of paints and coatings.
Talc can also increase the viscosity of the paint. Consequently, it will facilitate the convenient and easy dispersion of paint.
When it comes to automobile or industrial powder coatings and paints where there are very fine and micronized particles, fine and readily micronized Talc can fill up even the smallest spaces when metallic surfaces are covered by powder coatings and paints.
Due to its lamellar (platy and layered) structure, it reinforces paint films by improving adhesion. As a result, it prevents cracking and peeling of the paint from the walls.
Talc enjoys a better thermal conductivity when it compares to polymer and that means a quicker transmission through the mixtures is achieved when Talc is used. As a result, plastic compounds are processed and cooled faster due to presence of Talc.
Filled polymers with fine and lamellar Talk powder, are able to withstand more strain without deformation in comparison with unfilled polymers. Moreover, Talc powder gives a much higher creep resistance when it compared to other mineral fillers.
Talc is basically a soft mineral and simply micronized to fine particle sizes. That makes Talc a very good option to fill up the very small spaces within polymer compounds which increases the impact strength as well as stiffness of plastics and polymers.
Being soft and chemically inert, powdered Talc lowers the abrasion to paper machine fabrics and mechanical parts during the production process. Talc is also having a lamellar (platy and layered) structure and it can spread across the surface and make lower spots, minimize defects and holes in final output of paper.
Talc is organophilic and hydrophobic in nature. Thus, when it’s used in pulp processing, it will reduce the tackiness arising from stickies like plant resins and provide pitch control by preventing agglomeration on machineries of production line as a result.
It also improves the important characteristics such as ink gloss, scuff resistance and optimum ink transfer which will consequently increase the printability of finished paper. Whiteness of Talc will also improve the whiteness of final paper output.
Micronized Talc provides with a smoother finish which increase the quality of printing and the high opacity of Talc improve the opacity of the finished paper.
Talc powder is also used in ceramic industry due to its physical and chemical properties. As it’s having a high thermal resistance, it will improve the resistance against the thermal shocks of ceramics and reduces the fractures as a result.
Talc powder improves the resistance of ceramic against the acids since it’s a chemically inert material and has considerably low reactivity with acids.Due to low iron content as well as high magnesium content of Talc powder, it improves the whiteness when it’s used in ceramic production process.
Pure Talc helps to prevent the water leakage in sanitaryware since it’s hydrophobic in nature. Moreover, customization of Talc based on customers’ needs and requirements is basically achievable since the grinding process of Talc is controllable.
Talc powder is also used in many other industries like food processing, cosmetics, drugs and pharmaceutical, etc.
In food processing, due to its lamellar structure, it provides a shiny polish when applied on outer surface of pulses. Moreover, it avoids stickiness between the pulses.
In cosmetics, Talc is the basic ingredient of almost all cosmetics in powdered form because of its oil absorption characteristic. It has also a good oil absorption capability which is required in some cosmetics.
In pharmaceutical, it provides required lubrication when applied on outer surface of capsules and tablets and facilitate the swallowing process. It has also many positive advantages which is in line with requirements of pharmaceutical products.
