Development and application of silica sol in gansu precision casting factory

Silica sol inorganic polymer coatings have been developed in recent years.The key technique to prepare the coating is to remove the water-soluble sodium ions from the water glass by a special method.In general, it can be achieved by ion exchange, acid neutralization, water decomposition, electrodialysis and other methods to generate an extremely fine colloidal aqueous solution of silica ultrafine particles with particle size of 580nm (general emulsion particles are 800-1000nm), in which the content of Si2O is 20%-30%, the content of Na2O is 0.3%, and the ratio of silicon oxide to sodium oxide is more than 40%.Silica sol inorganic polymer coating is prepared by using silica solution/gel as base material, pigment and various additives.When the silicon solution loses water, monomer silicic acid gradually polymerizes into high poly silica gel. With the evaporation of water, colloidal molecules increase, and finally form -sio-o-sio-coating film: io-si-oh + ho-si-oh has the property of certain amount of film-forming dissolution due to the low content of NA2O in silica sol, and its water resistance and heat resistance are obviously better than that of organic coating.The coating film is dense and hard, does not produce static electricity, the dust in the air is difficult to adhere to.In the present architectural coating, its anti - pollution ability is stronger.

Fine particles, have a strong penetration to the base, can penetrate through the capillary to the base inside, and with the concrete base in the reaction of calcium hydroxide calcium silicate, so that the coating has a strong adhesive force.

But the volume shrinkage of silica sol is large in the process of film formation, and the coating film is easy to crack.Silica sol can be dissolved with acrylate, vinyl acetate and other emulsions.The properties of the two are complementary to each other, and the organic and inorganic composite coatings with excellent properties can be prepared.

   Use of silica sol in precision casting factory

1. Used for all kinds of refractory binder, with strong cohesive force, resistance to high temperature (1500 ° C to 1600 ° C), etc.

2. Used in the coating industry, can make the coating firm, but also anti-fouling and dustproof, anti-aging, fire prevention and other functions.

3. Used for precision casting of thin shell, which can make shell mold strong and casting smooth. The moulding quality is better than that of sodium silicate moulding. Replacing ethyl silicate moulding can reduce the cost and improve the operating conditions.

4. Silica sol has a high specific surface area and can be used for catalyst manufacturing and catalyst support.

5. Used in papermaking industry, it can be used as anti-adhesion agent of cellophane, pretreatment agent of photographic paper, anti-skid agent of cement bag, etc.

6. Used as sizing agent in textile industry, it can be combined with oil agent to treat the spinnability of wool and rabbit hair, reduce the breakage, prevent flying, improve the yield and increase economic benefits.

7. Used as silicon steel sheet treating agent, picture tube dispersant, floor wax anti-skid, etc