Paper Industry and Talc
Paper Industry uses talc both in uncoated and coated rotogravure, where they enhance print-ability and reduce surface friction, improving productivity at the paper mill and print house. They also improve mattness and reduce ink scuff. Used as pitch control agents, talc “clean” the whole manufacturing process by adsorbing any sticky resinous particles in the pulp onto their platy surfaces, thereby preventing the agglomeration and deposit of these stickies. As opposed to chemical pitch-control products that pollute the process water, talc is removed together with the pulp, enabling the industry to operate more easily in closed-circuit. In specialty papers, such as colored papers or labels, talc helps to improve quality and productivity.
Talc as coating agent improves the tactile properties and printability of rotogravure paper. Talc as a soft and platy pigment increases compressibility and maximizes ink transfer, thus reducing missing dots and print mottle and improving the opacity of the printing. The improved ink setting results in a lower smearing tendency
2. Pitch Control
Impurities such as pitch, white pitch and stickies are a problem for paper, coated broke, and chemical, mechanical or de-inked pulp processing. A high amount of colloidal pitch particles can cause pitch agglomeration. Some organic or inorganic compounds or ions are often the reason for agglomeration. Hydrophobic talc permanently adsorbs colloidal pitch and organic substances, which can build up agglomerates together with pitch. Talc decreases the tackiness of stickies, prevents agglomeration of these compounds and keeps them in a harmless form. Talc reduces deposits in the chemical and mechanical pulp processes, as well as in paper and recycled paper processes – regardless of changes in the process temperature or pH. Talc prevents the forming of secondary stickies (dissolved and colloidal stickies). This results in clean process equipment, improved plant productivity, and paper quality (fewer spots, defects, holes).
For de-inked pulp and recycled fibre, talc improves the removal of stickies in the flotation step and in cleaners. The quantity of added talc is flexible and it interacts safely with other raw materials or chemicals. In addition, talc acts as a filler in the end product.
Talc cleans paper and pulp of impurities with no need for chemicals or chemical cleaning systems. This means that wastewater is cleaner and has a lower chemical oxygen demand (COD). Energy consumption is reduced, and the production of recycling paper is facilitated.
In the paper and board industry, talc is used as a functional filler. Super-calendered, paperboard and raw stock for coated paper also benefit from talc.
The strength potential is increased, this offers cost saving options – either by a higher fresh filler load which replaces fibre, higher web strength with the same filler load or the use of lower cost raw materials.
Print-ability and Runnability
As part of the mineral filler composition in printing paper grades, the very platy shape of the soft filler talc leads to a smoother, more compressible and less porous sheet character. It avoids print mottling on uncoated grades and reduces surface friction – resulting in improved printability, runnability and process efficiency. The softness of filler talc lowers the abrasion of paper machine fabrics and mechanical elements.
Coating Colour Control
In the base paper of coated grades, talc helps to control the penetration of coating colour, giving quality advantages to the coated final product, combined with cost reductions.
Microtalc for Wet Opacity
When used as a filler in combination with titanium dioxide, specially designed talc grades can extend the highly desirable wet opacity properties of this more expensive mineral. This is the case in a variety of decor base paper grades and in other wood-free specialty grades.
Moisture Resistance and Efficient Drying
The hydrophobic, highly platy properties increase the moisture resistance of the sheet and improve the drainage and water removal on the wire section. The quick drying hydrophobic talc lowers energy consumption in the drying section and leads to appropriate savings.
Compared to other filler materials, talc has a high affinity to fibre combined with a platy nature that supports easy water drainage. Less of this filler is lost in the wire waters due to high retention.
Blanc Fixe talc lumps exhibits all the characteristics needed to make micronized talc for the industry. Our talc lumps have highest whiteness and brightness, it has lowest content of abrasive minerals.