HYDREX® sodium magnesium aluminosilicate and ZEOLEX® sodium aluminosilicate grades provide folding boxboard, white top, high brightness and opacity and reduce unattractive mottling. In addition to improving product aesthetics, they improve economics by reducing the need for expensive chemical pulp and can additionally cut costs by replacing titanium dioxide if needed.
Carbonless Copy Paper
For carbon-free copying, a paper must have fast color development, a high brightness and deliver uniform quality. This is exactly what ZEOCOPY™ sodium aluminosilicate offers reliable copying paper, without carbon, every time.
Mechanical Printing Papers
For newspaper, improved news-print, and directory paper HYDREX® and ZEOLEX® silica grades provide excellent brightness and opacity, improved color printability, less print-through in coldset-offset and flexo printing, and a higher friction during the winding process.
Delicate papers such as envelope paper or thin printing paper are particularly at risk for print through. HYDREX® and ZEOLEX® silicates reduce print-through in flexo printing while simultaneously offering high opacity.
Specialty Paper Printing
In decor and filter tipping paper, HYDREX® and ZEOLEX® silicates offer titanium dioxide extension, superior brightness, and improved print quality.
During the mechanical bleaching process, stabilizers are needed. ZEOPOL® liquid sodium silicate stabilizes hydrogen peroxide and additionally serves as a pH buffer and an aid in the complexation of metals.
ZEOCORE® is a modified liquid sodium-silicate based core adhesive which is ideal for high strength and heavy duty cores. It offers excellent core strength for a competitive price.
For fine paper and board ZEOFLOC® silica grade offers excellent dewatering performance, improved filler and fiber retention, and good formation. ZEOFLOC® is a temperature activated polysilicic acid.
HYDREX® is a synthetic magnesium aluminosilicate manufactured by precipitating sodium silicate solution with a mixture of magnesium and aluminum sulfate. It is used as a filler in wood-containing printing papers as well as wood-free fine paper and multilayer board to improve optical performance, printability and friction. The precipitating conditions for HYDREX® are carefully engineered and controlled. Thus the size and form of the primary particle of the agglomerates are carefully designed and maintained. HYDREX® is manufactured using raw materials thoroughly approved by Evonik in order to ensure a consistent high quality product free of contaminants. HYDREX® maintains a Food and Drug industry level of purity. Due to the pigment precipitation technique, no dispersion aids are required. The synthetic origin of HYDREX® allows long shelf life without the need for biocides.
HYDREX® sodium aluminosilicate significantly improves the opacity of paper. This is because the light scattering ability of HYDREX® is very high, almost 500 m²/kg. Thus it is able to enhance the paper's light scattering almost tenfold compared to fiber. The chemical composition of HYDREX® results in a high refractive index. HYDREX® provides the paper with a significant number of light scattering interfaces between air, pigment and fiber. This gives HYDREX® the power to increase opacity at low addition levels. HYDREX® inherently is an ultra-bright pigment, and it significantly increases the brightness of paper. While maintaining paper brightness, bleaching can be reduced, resulting in substantial cost savings.
HYDREX® sodium aluminosilicate improves the paper's printability: The high absorption capacity of HYDREX® increases the print image density thus reducing ink demand. HYDREX® keeps the ink at the paper surface and prevents the ink from migrating into the sheet. HYDREX® reduces strike-through and show-through by preventing ink and solvents from penetrating the paper. As a result, opacity is maintained. HYDREX® can also help in reducing registration problems in multicolor printing presses by increasing paper friction.
Certain furnishes tend to produce paper which has a low coefficient of friction. This can cause winding problems like snaking of the paper web, wrinkles, loose winding and telescoping of the reels. Another problem is slippage during paper transport, which shows up as breaks at the printing house. HYDREX® sodium aluminosilicate can solve all of these problems. Typically 1% Hydrex in the web increases the kinetic coefficient of friction by 15 %. At the same time an increase in optical properties can be noted.
Most pigments for filler or coating use tend to cause wear of the paper machine's parts like wires, foils and suction boxes. Also, printing presses and slitter knifes are subject to abrasion. Synthetic silicates reduce the wear substantially due to their amorphous nature with rounded surfaces and pores. In addition HYDREX® is free of abrasive contaminants. As a result, the abrasiveness of HYDREX® is very low.