CASE Newsletter 01/2026

Heraeus is an internationally active family-owned company with over 160 years’ experience in the development and processing of sophisticated materials. As a distribution partner, STOCKMEIER Chemie markets the product Zandosil® 30. This is a high-purity, pyrogenic silica with an exceptional profile of properties. This sets it apart from the competition. As a synthetically produced, amorphous silicon dioxide, Zandosil® 30 is manufactured using a flame hydrolysis process at temperatures between 1,000 and 2,000 °C from chlorosilanes such as SiCl₄. This thermal manufacturing process results in a three-dimensionally branched aggregate structure with a defined primary particle size and an extremely low impurity content. Zandosil® 30 is produced in Germany and achieves an exceptionally high degree of purity of 99.99 to 99.999%. 

A characteristic feature of Zandosil® 30 is a BET surface area of approximately 30 m²/g, combined with a comparatively large primary particle size of around 100 nm. This sets the product apart from conventional highly dispersed types. The larger particle structure results in a significantly reduced specific surface area and thus a lower thickening effect. This is precisely where one of the key competitive advantages of Zandosil® 30 lies. It enables a functional additive effect whilst having a minimal impact on system viscosity. Whilst conventional high-surface-area silicas have a strong structural viscosity effect and can cause formulations to thicken rapidly, Zandosil® 30 allows for high loading levels and excellent processability – a decisive advantage in high-solid and ultra-high-solid systems. The unique particle architecture also has a positive effect on dispersibility and surface modification. In coating systems, Zandosil® 30 enables effective control of rheology and thixotropy, improves flow properties and prevents sedimentation and sagging. At the same time, scratch resistance can be significantly improved, for example in UV-curing parquet coatings, where better results have been achieved in the Taber abrasion test. In terms of matting efficiency, Zandosil® 30 delivers 60° reflectometer values comparable to those of established matting agents, combined with a controlled surface texture. Another important area of application is the field of polymer films. 

As an anti-blocking additive, Zandosil® 30 creates a micro-rough surface structure that reduces the contact area between films, thereby ensuring efficient separation. At the same time, the relatively large particle size maintains good transparency – a crucial factor in packaging applications. Compared to conventional anti-blocking types, Zandosil® 30 offers the additional advantage of extremely high chemical purity, which is particularly relevant for food-grade or regulatory-sensitive applications.

Furthermore, Zandosil® 30 improves a wide range of physicochemical properties of polymers and coatings. These include the optimisation of dielectric properties, the modification of optical parameters, the increase in density and hardness, and the targeted adjustment of surface roughness. In powdered systems, the product acts as an absorbent to prevent moisture absorption and caking, whilst simultaneously improving flowability. In ceramics, it can be used to control sintering activity, whilst in the sol-gel process it serves as a high-purity raw material for the production of high-quality glasses.

The unique selling point of Zandosil® 30 therefore lies in its unique combination of extremely high purity, large primary particle size and low specific surface area. This combination enables maximum functional performance with minimal rheological impact on the system. Zandosil® 30 is therefore positioned not as a conventional highly dispersed structural silica, but as a strategic performance additive for demanding high-performance formulations where purity, process stability and controlled surface effects are paramount.

BRB is a supplier partner of STOCKMEIER Chemie, which was founded in 1981 and develops and manufactures silicones, additives and speciality lubricants worldwide. Its portfolio includes, in particular, silicone-based solutions, lubricant additives and chemical intermediates. BRB has been part of the PETRONAS Chemicals Group (PCG) since 2019.

Under the brand name SILOEN®, BRB offers high-performance water-repellent agents for the protection of mineral building materials. Water repellency plays a key role in modern building protection, as moisture is one of the most common causes of structural damage. Silanes, siloxanes and silicone resins from the SILOEN® range penetrate deep into mineral substrates, where they react chemically with the surface to create permanently water-repellent structures without leaving a visible film and whilst maintaining high water vapour permeability.

Various products are available for the retroactive surface hydrophobisation of concrete, stone or brick: 
• Siloen® 694 for highly alkaline substrates such as concrete, offering high penetration depth and a chloride barrier effect. 
• Siloen® SR 619 / SR 608 as versatile silane/siloxane concentrates. 
• Siloen® 5022 WR / WRE as water-dilutable emulsions with low VOC content and strong beading.
• Siloen® WRC4 / WRC8 as thixotropic creams for vertical surfaces and retrofit horizontal barriers. 

In addition to surface treatment, integral water repellency is becoming increasingly important: additives are incorporated into the building material directly during the manufacturing process, ensuring that the entire cross-section becomes water-repellent. Examples include: 
• Siloen® 696 for concrete and mortar, 
• Siloen® 882 for fibre cement, 
• Siloen® MXP 5 as a powder additive for dry mortar.

For coatings, plasters and façade systems, BRB also offers specialised additives such as:
• Siloen® HPA 406 to improve beading and dirt resistance, 
• Siloen® SR 403 for the hydrophobisation of polymer-bound plasters, 
• Siloen® HPA 415 for pH stabilisation and to improve water and abrasion resistance in emulsion paints.

All SILOEN® products are based on a common mechanism of action: silanes and siloxanes chemically cross-link with the mineral surface to form a deep-penetrating, permanently hydrophobic network. This significantly reduces capillary water absorption whilst maintaining diffusion openness.

With their high weather resistance, efficiency and versatility, BRB’s SILOEN® Water Repellents offer reliable protection for many applications – from concrete structures and natural stone façades to dry mortars, fibre cement and modern façade systems.