The production method of pyrogenic highly-dispersed silicon dioxide involves the process which is based on
continuous vapour phase hydrolysis of silicon tetrachloride SiCl4.
The first mass production of fumed silica has been launched in 1944.
During the process, the silicon tetrachloride in gas phase reacts with water forming in H2-O2 flame, with the
reaction temperature 1000°C:
2H2 + O2 + SiCl4 → SiO2 + 4HCl
The only by-product formed is hydrochloric acid that is
Microscope image of particles agglomerates utilised and processed according to the strict
environmental standards.
By varying the concentration of the reagents, flame temperature and dwell time of the silica in the
combustion chamber, it is possible to influence the particle size, particle size distribution, surface area and
surface properties of silica within wide limits.
Application in Different Fields
It is used as a filling agent in dozens of applications, due largely to unique properties of the particles: ultra
fine size, homogeneity, spherical shape and utmost purity. When added in liquids, it causes thickening effect
that is of significant importance for the production of lubricants, lacquers, paints, glues and medicines.
1. Adhesives and sealants
Fumed silica is effective and integral component in adhesive
and sealant systems. With addition in glues, it prevents
sedimentation, enhances viscosity, provides less setting time,
reduces stretching of fibres (filaments) in glues and increases
adhesive power dramatically. Apart from thickening effect,
fumed silica secures the desired mechanical strength of a
sealant when the latter is cured.
Silicone sealants feature the following particular traits:
• Good weatherability and resistance in aggressive environment
• Enhanced adhesion to most of construction materials without priming
• Excellent movement accommodation (no less than 20%)
• Improved thermal and cold resistance – maintains performability (remains resilient and elastic) within
temperatures -50° to +200°C
• Easy handling in wide temperature ranges (surface applications -30° to +60°C)
2. Pharmaceuticals and cosmetics
In pharmacy, the product has found its application as an inert
carrier and stabiliser of the active ingredient.
The silica provides desired consistency for pastes and ointments
and prevents separation of components as well. Also, it is used as
an auxiliary for the production of drops and pills.
In medical applications, the most crucial advantage is that all the
substances adsorbed on surface of the silica before, e.g. in
medicines, are then desorbed gradually and completely in aqueous
environment of human body, thus securing lasting effect and
enhancing performance of medicines.
Fumed silica is an enterosorbent, i.e. an agent that absorbs and removes substances harmful and toxic to the
body from intestinal tract.
Thanks to its absorbing ability, the silica outperforms greatly all the existing medical sorbents. Binding rate
for micro-organisms accounts for up 3 billion microbes in 1g of the sorbent. This extraordinary absorbing
effect is conditioned by the phenomenon of micro-organisms’ agglutination via particles of the silica.
Fumed silica is used on large scale in the production of toothpaste. It keeps teeth enamel safe providing
excellent polish and serves as a carrier of active ingredients in gel toothpaste.
3. Manufacturing of Plastics
Glass-fibre plastics are used exceptionally for the fabrication of plastic frames in shipbuilding, for which raw
materials like unsaturated polyesters (UPRs) and reinforcing glass fillers are required:
- in low-viscosity polyester resins with good wet-in features, fumed silica promotes levelling and prevents
cracking and sagging during the manufacturing of polyester-based glass fibre plastics.
- fumed silica delivers thixotropic properties to polyester and epoxy resins. Also, it can be used as antiblocking
agent in polymer films. In the production of PVC resins, the silica enables to adjust their operating
viscosity.
4. Paints and lacquers
Here, fumed silica functions as a stabiliser and anti-settling agent of
pigments and as an anti-sedimentation additive. It improves
thixotropic and rheological properties of coatings and paint systems,
retains original transparency of lacquers. Furthermore, addition of the
silica enhances hardening of coating film, adhesion to surfaces, as
well as reduces deterioration rate of the coatings and fading of
materials with transparent top coating. Besides, it helps to prevent
run-off and sag of paints applied on vertical surfaces, thus ensuring
top quality levelling. The silica is used as a matting agent of lacquer
systems, whereas the desired effect may be adjusted within wide
ranges.
5. Rubber industry
Fumed silica is active reinforcing filler used in the production of silicon rubbers. Primarily, the silica makes it
easier to prepare rubber mixtures by reducing sticking to the rollers. It is the most significant additive
designed to acquire lightweight durable and high quality colour rubbers used in the manufacturing of soles,
rubber cloths, sanitation and hygiene items, etc.
- fumed silica is easy to be mixed and disperses freely in rubbers.
It can be utilised in the following technological processes and products:
- in rubber-fabric articles to assure enhanced durability (hosepipes, belts, conveyors);
- in the fabrication of neoprene- and SKN-based items which are oil- and gas-proof.
- items subject to repeatedly bending (conveyor belt, rubber hoses);
Modified Grades of Fumed Silica
The methyl-modified silica is heat-resistant organophilic products which features hydrophobic properties. It is
obtained through chemical modification of ultra fine silica’s surface by means of chloroorganic silanes.
High dispersion and surface chemistry allow to add hydrophobic silica as a thickening and matting agent as
well as a reinforcing filler in different compounds. With addition in the formulation of varied paint and
lacquer systems, modified silica enhances water, thermal and frost resistance of coated surfaces and
provides their safety in aggressive environment not favourable to proper operation.
Hydrophobic silica enables to acquire non-porous silicone rubbers and mixtures that have longer life
performance in damp and wet form suitable for the fabrication of cable rubbers and other applications.
Tangible effect is seen in free-flowing materials where methyl silica is added as anti-caking agent. For
instance, in extinguishing powder chemicals, it increases their flowability and extinguishing effect by 6 to 7
times.
Multiple tests with modified fumed silica have resulted in the synthesis of heat- and water-resistant
lubricants that can be used in industrial applications.
Using of methyl silica as a filling agent in polymer compounds, as a thixotropic thickener in grease lubricants,
and as an additive preventing the settling in lacquers and paints secures manufacturing of high quality
products.

Hydrophilic

A-120
A-150
A-175
A-200
A-300
A-380

Hydrophobic

AM-1-175
AM-1-300
AMS K-7-30