PYROGENIC, HYDROPHILIC AND HYDROPHOBIC SILICA
Pyrogenic silica also known as fumed silica, are versatile and highly performing additives. They are use in a wide range of applications such as body care, cosmetics, pharmaceutical, cleaning products, food and industrial applications for adhesives, coating, zootechny and agri-chemical as rheology control, elastomer strenghtening agent, thixotropic agent, carrier and emulsifying agent.
Cabot – leader mondiale per produzione di prodotti chimici e materiali di performance – propone in aggiunta una vasta offerta di prodotti a base di allumina:
- SpectrAl® FA 100, very suitable for powder coating with corona or trio charging and in wood covering for wear resistance
- SpectrAl® FA 51 scrape resistance additive and touch modifier in coating applications
- SpectrAl® PC-401, scrape resistance additive and touch modifier in coating applications.
Cab-O-Sil is derived from vapour-phase hydrolisis of silicon tetraclhoride on hydrogen flame:
2H2 + O2 -> 2H2O
SiCl4 + 2H2O -> SiO2 + 4HCl
SiCl4 + 2H2 + O2 -> SiO2 + 4HCl
The combustion process creates molecules of silicon dioxide that condensate into particle which will collide with each other. The result is a tridimensional chain long 0.2-0.3 microns.
When these aggregates cool down from the melting point of silicone (1800°C), more collisions occur until a fine, soft white powder is formed, with clusters smaller than 325 US Mesh (44 microns).
Calcination reduces it to HCl with concentration lower than 100 ppm. High levels of purity can be achieved through this process.
The following Cabosil degrees (TS) have been produced through silica reacting with other compounds to add hydrophobic properties.
Untreated CaboSil are used as rheology agents, thixotropic agents and antigas agents for liquid systems, suspensing agents and powder anti-caking. The most popular one is CAB-O-SIL M-5, with 200 m2/g SSA. H-5 and EH-5 are SSA 300 m2/g and 380 m2/g, respectively. Usually, an increase in SSA is directly related to an increased thixotropic effect, however there’s also a decrease of ease of dispersion.
High SSA types require consistent agitations in watery mediums, however it also gives high efficiency to these Cabot products.
Treated fumed silica are produced by superficial reaction to silicone:
- CAB-O-SIL TS-720 completely treated with dimethyl silicone polymer, making it totally hydrophobic and suitable for medium rich in mineral oils and polar systems ed in grado di agire in mezzi ricchi in olii minerali e sistemi polari
- CAB-O-SIL TS-610 partially treated with dimethyldichlorosilane, less hydrophobic than TS-720, suitable as gelifying agent, suspension and thixotropic agent, both for water based and solvent based systems, as well as anti-caking for powders. Good aging effect on all systems.
- CAB-O-SIL TS-530 highly treated with hexamethyldisilazane. This makes it incredibly effective and can be used as anti-caking, carrier for liquid substances and to enhance product resistance to humidity, as well as being suitable as special free flow agent for powder coating due to its positive charges.
Cab-O-Sperse are water dispersions of fumed silica and fumed alumina. Excellent stability and optimal quality of dispersion, achieved by Cabot without surfactants or dispersants, makes these very versatile and compatible with a very wide range of formulations, due to the simplicity of use as additives: they can be added with a simple stirrer employing very little energy.
The chemical and physical properties for various fields of applications (anticorrosion and wear resistance in industrial use, fast-drying, adhesive enhancer…) can be fully employed without problems in the dispersing process.
SUPPORT AND ASSISTANCE
EICO Novachem supports its clients with special technical assistance to formulate new products, designed and customized to fit the client’s specifications. Indeed, we offer technical support and advanced and always updated certifications. EICO Novachem’s customer service is boosted by the assistance of the original producer. We are always available for any technical or commercial need and to help out with the formulation.
Our technologists are consistently researching new formulations, new products to better meet market needs. We also use new technologies in order to protect the environment, focusing on non-solvent-based, low metal content products. We pay close attention to sourcing eco-sustainable raw materials and we evaluate new technologies with an eye to respecting the environment, developing solvent-less and low-metal content products