First, the application status
Talc is widely distributed in the crust and lithosphere and has a large output, which can be widely used in the paper industry. Talc has chemical stability, low hardness, lubricity, lamellar structure, lipophilicity and hydrophobicity. These properties of talc in the paper industry can effectively improve the performance of paper. In China, more than 50% of talc production is used in the paper industry, and its uses mainly include paper fillers, coatings and resin control agents.
When used as a filler in the papermaking process, talc has the following advantages:
(1) It is good for improving the smoothness, opacity and printability of paper
(2) The wear value is small, which can extend the service life of the papermaking net
(3) It is chemically stable, not only suitable for acid papermaking, but also can be used together with calcium carbonate for neutral papermaking.
(4) It has a good combination with the sizing agent to keep the rubber material and prevent the printing ink from penetrating.
(5) It is lipophilic, can adsorb organic substances, keep white water and slurry system clean, and acts as a filler to eliminate resin barriers, and helps to remove ink in waste paper deinking.
(6) It has certain hydrophobicity and lubricity, can reduce the water absorption of the paper, improve the smoothness and softness of the paper, and reduce the operation obstacles such as calendering and finishing.
(7) It is beneficial to keep in the paper sheet and reduce the fiber consumption of the ton paper product.
As a coating pigment, talc has better fiber covering ability and printing effect, can improve whiteness, opacity, smoothness and printing gloss of coated paper, impart high ink absorption to paper, and improve gravure printing quality. And the talc is lubricious, and the coated paper made therefrom can obtain a high degree of finish on the calender and can reduce the amount of lubricant used in the paint. However, talc has corresponding disadvantages due to its hydrophobicity: it is difficult to wet and disperse in the preparation of coatings, and the finished coating has shear expansion property, low retention rate, and easy to cause paper to fall off. Therefore, some talc is Surface treatment is required before use.
Due to the oleophilic nature of the talc structural features, the application of talc to pulp and paper can effectively control resin and anionic viscosity. On the one hand, it can adsorb the gluey substance in the papermaking system, reduce the surface energy of the anionic viscous material, and lose its special viscosity, thereby inhibiting the adhesion, coalescence and deposition of the stickies; on the other hand, coalescence has occurred. Stickies can also adsorb talc, reducing the viscosity of the surface of the stickies and avoiding further coalescence and deposition.
In general, talc plays an important role in the paper industry with its unique hydrophobic properties. How to use the characteristics of talc to avoid and use it is still necessary to explore.
Second, the new talc products
At present, the new talc products that can be used in the papermaking industry mainly include cationically modified talc, solid paraffin and AKD modified talc, black talc, magnesium aluminum hydrotalcite and the like. Among them, the cation-modified talc powder can better absorb the anionic waste generated in the papermaking process when used in papermaking; when the talc modified by solid paraffin and AKD is used for papermaking filler, the paper can obtain higher resistance. The ability of liquid to penetrate, and the tensile strength of paper after AKD modification will also be significantly improved; the blackness of black talc after calcination ultrafine processing can reach more than 92%, and its original hydrophobicity will change, particle surface Presenting a porous structure, increasing its specific surface area and adsorption, theoretically can be considered for functional paper coating pigments (instead of part of TiO2 and calcined kaolin), as well as functional papermaking fillers and papermaking adhesive control agents, with potential market Development prospects; magnesium-aluminum hydrotalcite can improve the opacity and whiteness of paper when used in papermaking, and it has a good flame retardant effect.
Source : Network Information
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