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The Advantages and Operation for Silica Sol Casting
2016-02-24

Silicone rubber synthesis process is brief: reduction of silica sand or silicon monomer → temperature at 300 percent, with copper as a catalyst, silicon and methyl chloride interaction → form a mixture of methyl chloride silicon (mono , binary or ternary) → Separation by distillation of dimethyl silicon dichloride → dimethyl silicon dichloride silane and quickly hydrolyzed to the synthesis of a linear or cyclic siloxane → linear siloxane potassium (KOH) with the help of the formation of quaternary bismethyl annular body (D4) → in the presence of KOH, D4 polymerization, resulting in chain termination process is completed.

Below is the advantages of silica sol castings:

a. The surface finish we could meet is CT5-6.So the surface of products looks very smooth.

b. It is only suitable for small parts,for big parts,we prefer sand casting.

c. As the dimension accuracy is high,so there is no need to machining for some sections, which will save much machining costs and time.

d. Beside stainless steels, silica sol casting process is also used for casting small size alloy steels and carbon steels.

Silica inorganic polymer coating formulation process is no different from other special coatings, but silica should be added slowly, otherwise the paint qualitative change will occur. You can refer to the following preparation process:

The film-forming aid (commonly used are zinc oxide, butyl silicate, butyl acetate, methyl silicate, etc.) was added to the reaction kettle, stirred amount of water is added, and successively added surfactant (benzene sulfonate ), thickener (hydroxyethylcellulose, CMC, etc.), a dispersant (sodium hexametaphosphate), antifoaming agent (tributyl phosphate) and other additives; then slowly added to the silica sol, extender pigment paste . With a sand mill or a colloid mill fine, you can produce points need to be added coarse aggregate. Paint PH value between 8.5-10.

Silica inorganic polymer coating formulation:

Silica deposition contraction is large, the film is easy to crack, to overcome this drawback ,, in addition to adding the inorganic fibrous filler in paint, while also adding a water-soluble emulsion as auxiliary film-forming material, organic matter filled in "-Si -O-Si- ", reducing the network structure of the film formation temperature difference caused by the expansion and contraction of shrinkage change. That has become a kind of inorganic coating excellent weather resistance, but also with organic coatings as excellent organic compound paint decorative, stability and workability of. Generally it can be to test the filter: the inorganic film material accounted for 50% to 90% 50% 10% organic matter. Add inner polyvinyl acetate emulsion with time; add external use benzene - acrylic emulsion, titanium dioxide rutile first with a volume concentration of 5%, and adding a lot of extender pigment, a total volume of 60% to 70% concentration of speculation.

Silica concentration stage production is an energy intensive, long cycle process steps. Conventional concentration methods are usually used to reduce pressure dehydration method, so that to obtain the desired concentration of silica.

From sol exhibited different pH, silica sol is divided into basic and acidic silica sol. They are important fine chemical products, with different important purposes: alkaline silica sol precision casting, and other areas of exterior paint applications; acidic silica in the color picture tube, colloidal lead-acid batteries, as well as from abroad electrostatic-sik velvet art applications.

Ultrafiltration membrane concentration method of low energy consumption per unit of production, the more traffic a short period, less investment in equipment, which is a lower product cost, effective way to improve product quality.

Ultrafiltration is a more advanced method for the preparation of a silica sol. It is to use ultrafiltration ultrafilter concentrated. Ultrafilter with different filters, ultrafiltration membrane ultrafilter used to allow only water and soluble salts by sol particles allowed through. This indicates that the method is effective, it can not only remove water dilute sol, but also to remove a small amount of soluble ions or substance. But it does not allow the ultrafiltration membrane of cake or precipitate appears, it must be subjected to ultrafiltration under constant stirring. Can ultrafiltration as intended purpose, the key is to have a suitable ultrafiltration membrane. More information about Silica Sol Precision Casting, you are suggested visit tosing-casting.com