01 silane coupling agent dosage

The amount of the silane coupling agent is determined depending on the amount of the reaction site (such as Si-OH) occupied by the specific surface area of the powder, the thickness of the monomolecular layer covering the surface of the silane coupling agent, and the thickness of the multi-molecular layer.

Generally, the silicon micronized mineral powder has a Si-OH content of 4 to 12 μm 2 , and 1 mol of the silane coupling agent can cover a powder surface area of about 7,500 m 2 . Since the silane coupling agent is hydrolyzed, it also produces a condensation reaction itself, which affects the accuracy of the calculation amount, so it is necessary to increase the amount of addition.

The calculation relationship of the amount of silane coupling agent is:

Amount of silane coupling agent (g) = powder mass (g) × powder surface area (m2 / g) / coverage area of silane coupling agent (m2 / g)

02 Determination principle of surface modification process

Determine according to the mechanism of reaction between the selected silane coupling agent and the silicon micropowder:

First, the silicon micropowder is first dynamically heated to 100-110 ° C. At this time, the hydrolyzed silane coupling agent or composite coupling agent is added by atomization.

Second, the silane coupling agent should maintain a certain reaction time during the reaction, and the modification effect is different due to different reaction time. This heating reaction process is dehydration, condensation and solidification to form a stable and strong covalent bond between the silane coupling agent and the silicon micropowder.

Third, the powder modified by the coupling agent will produce pseudo-knot particles and hard particles generated after condensation, which will have a great impact on the quality of the product, so it is necessary to carry out effective grading. Only in this way can the quality of the product be guaranteed. .

03 Selection of surface modification equipment

The selection of silicon micropowder surface modification equipment should be based on the processing technology determined by the surface modification mechanism, and select and support non-polluting surface modification equipment. At present, there are many surface modification equipments in China, but some surface modification equipments are not manufactured according to the mechanism and process requirements of surface modification of silicon micropowder, which results in poor surface modification. Therefore, it is necessary to purchase modified equipment. After the transformation and matching, the better results can be achieved.

The choice of surface modification equipment is a key part of the surface modification of silicon micropowder. When selecting surface modification equipment, the following requirements should be considered:

First, the surface modification equipment can heat and keep the silicon micropowder under dynamic conditions, and the holding time can be automatically controlled.

The second is to have a venting device, which can discharge the water removed before and after the surface modification in a vapor manner, thereby causing a condensation reaction between the silane coupling agent and the powder to achieve the effect of forming a covalent bond.

The third is to ensure that the silicon micropowder is in a high-speed dynamic state in the surface modification machine.

Fourth, the surface modification equipment should meet the requirements of the addition of surface modifiers.

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