Key advantages of GCC in paper and packaging production
Increased whiteness: GCC has high whiteness, which improves print sharpness and the visual appeal of paper. The addition of calcite increases light reflection, giving the paper a brighter, “snow-white” shade.
Efficient light scattering: Ultra-fine GCC particles scatter light, increasing sheet opacity and reducing print show-through on the reverse side. As a result, hiding power is improved – the ink does not penetrate deeply into the sheet and does not show through, which is especially important for double-sided printing.
Note: Typical GCC grades with an average particle size of ~1–2 μm are used for high-quality coated paper requiring maximum whiteness and hiding power.
Increase in paper stiffness: GCC used as a filler can increase sheet stiffness and thickness, which improves the strength of packaging materials. Coarser micro-calcite particles act as a kind of “framework”, increasing paper thickness at a given basis weight and thereby increasing its bending resistance without loss of elasticity. As a result, board or paper becomes stiffer without an increase in grammage per square metre.
Higher bulk at lower density: Due to its lower density compared with fibre, GCC increases paper bulk, allowing the sheet weight to be reduced without loss of its key performance properties.
Alternative to TiO₂ and kaolin: GCC acts as a functional extender, reducing the need for expensive white pigments (such as titanium dioxide) and fillers like kaolin. The transition to filling with micro-calcite has enabled producers to achieve the required brightness and opacity with minimal addition of TiO₂. Compared with kaolin, 1-micron micro-calcite grades often have higher brightness and more effective light scattering, which makes it possible to achieve similar optical properties at lower raw-material cost.
Reduction of production costs: By increasing the share of GCC in paper formulation, producers reduce their dependence on more expensive components (titanium dioxide, kaolin, thickeners, optical brighteners, etc.) and lower the overall formulation cost, while maintaining the specified printability, strength and durability of the material at a lower cost price.
Better ink absorption and setting: Mineral loading of the paper creates a more uniform and smoother surface for printing. Paper products based on GCC control the absorption of the binding components of inks, ensuring their reliable adhesion to the surface and high colour strength. As a result, prints are sharp and vivid, without blurred contours.
Reduced paper dusting: A smooth, well-sealed surface containing GCC reduces the formation of paper dust and lint during high-speed printing, improving print quality and preventing contamination of printing presses. Mineral particles fixed in the coating structure reduce the amount of free fibres that can detach during printing, thereby increasing the paper’s resistance to abrasive impacts from printing equipment.
Natural eco-friendly filler: Calcium carbonate is a natural mineral, non-toxic and biodegradable, used in papermaking. Its use contributes to more environmentally friendly paper production, as it makes it possible to reduce the share of wood fibre and chemical pigments. In addition, the alkaline nature of GCC improves paper durability: the mineral filler neutralises acidic residues and acts as a buffer, slowing the ageing and decomposition of cellulose over time. This is why paper with an alkaline pH is known for its high archival permanence.
Reduced carbon footprint: The production and use of GCC is less energy-intensive compared with synthetic pigments. Replacing part of the cellulose and synthetic additives with a natural mineral helps reduce energy and water consumption, as well as simplify waste-paper recycling, since mineral fillers are easily removed during paper reprocessing.
Note: All GCC fractions (from 1 to 5 μm) contribute to the sustainability of paper products; however, the finest grades are particularly in demand in “green” papers with a focus on recyclability and a minimal environmental footprint.
Applications of GCC in paper and packaging production
Improved print sharpness: The introduction of GCC increases paper brightness and reduces its transparency, which makes the printed image appear more contrasted and sharper. Ultra-fine micro-calcite filler improves light scattering within the sheet, preventing ink show-through and enhancing colour perception.
Smooth surface for high-quality printing: Mineral pigments fill micro-irregularities on the sheet surface, giving it uniformity and smoothness. This reduces the likelihood of defects in offset and digital printing, such as unprinted areas or uneven ink absorption. Smooth coated paper with ultra-fine micro-calcite provides excellent reproduction of image details and high print quality without additional calendering, enhancing optical properties.
Increased stiffness and bulk: The addition of coarser GCC fractions (3–5 μm) in board production increases its stiffness and thickness. This gives cartons and corrugated board the required shape stability and strength. Due to the mineral filler, it is possible to achieve the necessary rigidity of the structures even with a reduced board weight. Sheets gain additional bulk without an increase in density, which is especially important for strong consumer and transport packaging.
Strength with reduced weight: The use of GCC makes it possible to lower board density by partially replacing heavy fibres with a lighter mineral, while the overall mechanical strength remains almost unchanged. The producer can use lighter board (with a lower basis weight) without loss of stiffness, which saves cellulose raw material and reduces product cost. Such boards are easier to recycle and requires fewer resources during transportation.
Increased softness and smoothness: In tissue, office and other thin papers, small amounts of highly dispersed GCC can provide additional surface smoothness. Mineral particles fill micro-voids between fibres, making the paper feel softer to the touch. The “silkiness” of the texture is improved, which is valuable for sanitary and hygiene products (tissues, towels) and decorative papers at minimal micro-calcite dosages.
Increased bulk at reduced weight: In some specialty papers (for example, thin packaging papers, laminated papers, label bases) GCC helps increase thickness and opacity without adding weight to the material. Coarser particles (2–3 μm) act as micro-spacers between fibres, increasing sheet bulk. This makes it possible to obtain light yet sufficiently strong papers that also have good liquid absorption.
Cemix offers high-purity GCC grades specifically designed for use in paper and packaging production. Optimal particle size distribution, high brightness and excellent dispersion properties provide economical and efficient solutions.
By using GCC from Cemix, producers gain benefits in the form of improved printability, increased bulk and enhanced resistance to external influences.
Contact us today to obtain customised solutions for the paper and packaging industry.
Ground calcium carbonate plays an important and indispensable role in improving the properties and cost efficiency of various types of fibre-based paper and packaging products – from corrugated board and folding cartons to flexible packaging and high-quality coated paper. Its effects in different segments are described below:
In fibre-based packaging (cartons, corrugated board, boxboard) GCC increases stiffness, improves printability and enhances the sustainability of packaging while at the same time optimising production costs:
Higher bulk and stiffness: Additions of GCC (approximately 3–5 μm) increase the thickness and hardness of board, enabling a transition to lighter structural solutions. Packaging remains strong even with a reduced cellulose content, which saves raw materials and lowers product cost. Thanks to the filler, it is possible to produce strong corrugated packaging with a smaller number of layers or lower paper grammage without loss of compression strength.
Improved printability: Fine GCC (1–2 μm) makes the surface of packaging paper smoother, enabling clear strokes, text and images to be printed on cartons. Even on boxboard, printing of logos and markings becomes more contrasted and uniform thanks to the mineral filler. In addition, in some coated packaging grades, calcite helps create a barrier layer: it fills pores and, together with binders, improves the surface resistance to oil and moisture (which is important, for example, for impregnated or laminated boxes for food products).
On board (folding cartons, liquid packaging board, food boxes) GCC increases base strength, coating efficiency and visual appeal, providing high-quality packaging solutions:
Higher hiding power and whiteness: In the top layers of board for cartons, the introduction of GCC increases the brightness and colour stability of the packaging. A coating containing fine calcite (~1–2 μm) acts as a pigment that improves hiding power at lower ink consumption: the mineral reduces ink penetration into the sheet and promotes more uniform drying on the surface. This increases print sharpness and colour intensity on the packaging, giving it an attractive appearance.
Barrier properties: In coated cartons for food products (for example, beverage cups, fast-food trays) GCC is part of barrier coatings that enhance the material’s resistance to fats, moisture and gases. Mineral particles in combination with special polymers form micro-barriers that hinder the penetration of oils, water and oxygen. This is important for preserving the taste and freshness of packaged products. At the same time, such coatings remain environmentally friendly and suitable for recycling, as they contain less plastic due to its partial replacement with mineral.
In flexible packaging and specialty papers (labels, packaging papers, laminated materials) GCC improves base flexibility, coating properties and printing performance:
Optimisation of coating layers: The addition of highly dispersed GCC (1–2 μm) to the coating layer of labels and wrapping papers enables more precise control of gloss, smoothness and ink absorbency. The mineral pigment can provide either matte or high-gloss finishes depending on requirements, and ensures good ink adhesion without smudging. As a result, labels have crisp images and a pleasant appearance, while flexible packaging materials obtain the desired surface texture.
Weight reduction and increased strength: Using GCC particles of medium size (2–3 μm) makes it possible to produce thinner film-based or paper-based materials with improved mechanical performance. The filler increases thickness and stiffness of such materials, allowing overall fibre or polymer consumption to be reduced. For example, laminated paper containing GCC can be thinner yet sufficiently resistant to tearing or puncture. This reduces packaging weight and transportation costs while maintaining functionality. In addition, the mineral’s presence facilitates recycling – it is inert and easily removed during reprocessing of the paper base.
In graphic papers (magazines, illustrated editions, premium print products) GCC optimises brightness, print quality and surface smoothness, turning them into genuinely premium products:
High brightness and hiding power: GCC maximises light scattering within the sheet, increasing paper whiteness and reducing ink show-through. This is particularly important for thin coated papers used in magazines: even at low basis weight they remain opaque. In premium paper grades, calcite often partially replaces expensive titanium dioxide, making it possible to achieve the required optical properties at significantly lower cost.
Improved print sharpness: The mineral filler reduces excessive ink absorption into the paper, so halftone dots remain sharp and images become more defined. Printing inks set more quickly on the surface without spreading, which provides high brightness and contrast of images. Magazine printing on paper containing GCC is characterised by greater detail and richer colours.
Smooth surface: GCC contributes to the formation of an even, smooth surface, which reduces dusting and wear of paper during high-speed printing. The surface layer becomes more robust and less prone to linting (release of fibre particles), which allows offset presses to run more stably, without stoppages for cleaning. In addition, smooth paper prevents the spreading of microdroplets of ink (in digital printing), ensuring accurate reproduction of the finest design elements.