Use Fumed Silica as Anti-sedimentation Agents
Risk aversion plunged on the positive news of the Russia-Ukraine talks. After several days of rising oil prices, the price of precious metals continued to fall. Domestic futures markets remain stable for the time being.
Back in international markets, WTI crude futures briefly dipped below $100 a barrel, while Brent crude hit its lowest intraday level in nearly two weeks. Spot gold briefly fell below $1,900 an ounce. Comex gold futures closed down 1.1 percent at $1,918.4 an ounce. Comex silver futures closed down 1.14 percent at $24.91 an ounce. "Recently, crude oil prices have been extremely sensitive to changes in geopolitical news." Traders believe that the current oil price is still in the broad impact, Ukraine will still be a premium in the case, although the market further decline, but should not be too pessimistic, it is recommended to wait and see for the time being. The Ukrainian premium is still there and there will be some volatility in the fumed silica market.
Fumed silica is a kind of inorganic nanomaterial with a small particle size, large specific surface area, and high surface activity.
It is mainly used as a rheological auxiliary agent in paint and coating, which can effectively prevent flow hanging and thick edges in the construction process and improve construction efficiency.
In addition, silica in the coating is also used as an anti-sedimentation and dispersant aid, can effectively prevent the sedimentation of the pigment delamination, improve the coating weather resistance, scratch resistance, and the bonding strength between the coating and the substrate.
Fumed silica is an ideal anti-sedimentation agent, its hydrogen bond structure is very stable and uniform, and it is a three-dimensional network structure, which is very effective to prevent the precipitation of pigment in the coating system. Especially for the color paste system, the appropriate amount will greatly improve the stability of color paste, and can reduce the amount of wetting dispersant, to improve the applicability of color paste and reduce the influence of color paste on the coating system. At the same time, the anti-sedimentation effect of fumed silica is very beneficial to the storage of coatings, especially some pigments such as metal powder and thin sections, which are easy to precipitate and cannot be completely suspended, the use of fumed silica can ensure that its dispersion does not precipitate.
The precipitation of fumed silica is very beneficial for coating storage and transportation. For some pigments, such as metal powder and thin film, it is easy to precipitate and cannot be effectively suspended. The use of fumed silica can ensure that the mixture is uniform and does not cause sedimentation. In absolute non-polar liquid phase, such as hydrocarbons (hydrocarbons) without hydrogen bond (chemical structure such as R-H) bonding ability, halogenated hydrocarbon (halogen and hydrocarbon electrophilic addition or substitution reaction) solvent, the viscosity recovery time is only a fraction of a second; Thixotropic recovery in polar liquids, such as hydrogen-bonded amines (R-NH3), alcohols (R-OH), carboxylic acids (R-COOH), aldehydes (R-CHO), and dialcohols (such as Ho-Rh2-OH, where R- is a saturated alkyl group), can take up to several months, depending on the amount of fumed silica added and the uniformity of mixing. The fumed silica is pre-dispersed and added to the finished paint. Usually, a high-speed dispersing machine or three-roller machine is used to improve the dispersion effect. If the dispersion is not good, the paint film will have particles, affecting gloss and aesthetics.
In addition, as an anti-sedimentation agent, fumed silica is added to coppery acrylic resin conductive coating. The test proves that it can make the thermoplastic acrylic resin thixotropic and prevent the deposition of filler particles, but if the addition amount is too much, the coating becomes a gel state, the conductivity of the coating would be reduced.
In the powder system, because of the small particle size and high surface energy, silica can be adsorbed on the surface of the coating powder, and form a surface layer on the surface of the powder to improve the dispersion of the powder. In the same coating system, the addition of fumed silica can obviously shorten the dispersion time and improve the production efficiency.
The addition of fumed silica in wall coating can effectively prevent coating from hanging, improve the flatness of the construction surface, and also greatly improve the washing resistance and aging time of exterior wall coating. The bonding strength of coating film and the wall is also greatly improved, the hardness of coating film is significantly increased, and the surface self-cleaning ability is also improved.
The adsorption of fumed silica on the surface of powder coating can form a movable layer and produce a "ball bearing" effect, which can prevent the powder coating from absorbing moisture and agglomerating and improve the fluidity of powder coating.
The main function of floor paint is the rheological control, improving the weatherability and scratch-resistance of floor paint, and improving the leveling performance of the coating.
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With Russia taking the lead on Poland and Bulgaria at the end of last month, there appears to be a growing sense of compromise within the EU over whether to accept Moscow's proposed rouble settlement order.
Italy's prime minister said recently that European companies would be able to buy gas in roubles without violating sanctions. This apparently ignores the guidance of hardliners in the EU to "fight to the end".
For weeks, European companies have been trying to find ways to meet Russia's payment demands for the rouble while maintaining vital gas supplies without violating sanctions against Moscow.
Late last month, European Commission President Von der Leyen said operating under the mechanism would violate sanctions and asked European companies not to bow to Russian demands. However, the EU has yet to issue more rigorous written guidelines on how companies should pay Gazprom.
The Italian prime minister said recently, "There is no official announcement from the European Union about what ruble settlement means for sanctions violations, and no one has said whether ruble payments violate sanctions or not. It's a grey area."
"In fact, most gas importers are already opening rouble accounts for deals with Gazprom,"
He also used German companies as a shield. He said Germany's largest gas importer had already paid in rubles. "In fact, we saw evidence yesterday that the largest gas importer in Germany has already paid in rubles."