What is silica gel desiccant?

2021-11-08   Pageview:311

The main component is silica, which is granular or bead-like made from natural minerals through purification and processing. As a desiccant, its microporous structure (average 2A) has good affinity to water molecules. The most suitable environment for silica gel to absorb moisture is room temperature (20-32 degrees Celsius) and high humidity (60-90%), and it can reduce the relative humidity of the environment to about 40%.













The polyether chain can be made from ethylene oxide, propylene oxide or a mixture of both. The structure of the polyether chain and the degree of polymerization n affect the polarity of polyether modified polydimethylsiloxane. For water-based coatings, the polyoxypropylene chain (CH2-CH-0 gives more hydrophobicity and makes
CH It is suitable for solvent-based coatings. The ratio and arrangement of ethylene oxide and propylene oxide can be controlled, and the degree of polymerization n can be changed, so as to adjust the degree of polarity or water solubility of the product (that is, control the degree of hydrophilicity and hydrophobicity of the product) to oxidized ft wax gloves make it It has good compatibility in high and low polarity coating systems.

In the molecule of polyether modified polydimethylsiloxane, I + y and z are two variables. The arrangement of work ten y, its arrangement and the ratio of the two all affect the slipping effect of the product in the coating. The size of it affects its compatibility with the coating base material, and the size of T + y affects the smoothing effect of the coating film and its ability to reduce surface tension. The smaller the value, the greater the work + y, the better the slipping effect. But if z is too small, it will reduce the compatibility of the product with the coating base material.
Experiments have proved that the polyether modified polydimethylsiloxane has obvious thermal degradation phenomenon at 130℃, and the higher the temperature, the faster the chain scission. After the break, or make the polyether chain leave the main chain, the active ingredient is changed to polydimethylsiloxane, or alcohol groups and aldehyde groups are generated at the break. This thermal degradation limits the use of polyether-modified polydimethylsiloxane, especially its use in baking paints.

Polyether modified polydimethylsiloxane products, such as BYK-300, BYK-301 (can be used for water-based coatings), BYK-306, 836, 863, BYK (Shanghai) Chemical Co., Ltd. produced by BYK 437 (can be used for water-based coatings), Tego-450, Tego-410 from Germany Tego Company (can be used for water-based coatings), EFKA-31, EFKA-30 (can be used for water-based coatings) from EFKA in the Netherlands, China Bestune Help HX-3390 and HX-3380 of the agent company.


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