How to control the oil absorption value of magnesium hydroxide

Magnesium hydroxide, as a kind of inorganic filler, has been widely used in many industries such as rubber, plastic, coatings, inks, medicine, food, etc.In the indicators related to the quality of magnesium hydroxide products, oil absorption value has a very important impact on product applications.

The oil absorption value is also called a resin adsorption, which means an index for the absorption of the resin.In addition to determining the chemical composition and purity of the powder material, it is also related to its surface chemical properties. The oil absorption value is different, then the particle size, comparison surface area, and adsorption performance of the powder are also different.The oil -absorbing value can change the compatibility of magnesium hydroxide and polymers, and it has a certain impact on the quality, performance and use of materials.

Two main forms of powder absorbing oil

In short, if the oil absorption value is large, it will “waste” a large amount of resin, and the effect of filling magnesium hydrogen oxide to reduce production costs will weaken. In addition, if the formula contains a liquid auxiliary agent, it should be selected with magnesium hydroxide with small oil absorbing value and inorganic powder with large oil absorption value. The required coupling agent will increase.

The way to reduce the oil -absorbing value of magnesium hydroxide

1. Control particle appearance

The high and low oil absorption value of magnesium hydroxide has a lot to do with the production process. In the case of no special requirements for particle appearance, crystal control agents can be used to control the crystal and comparison area, thereby reducing its oil absorption value.

2. Control fineness and particle size distribution

The application of magnesium hydroxide products in ordinary areas has not high requirements for fineness and particle size distribution. It can be appropriately selected for a complex product with a large granular distribution gap. In this way, the small particles will enter the gap of large particles, the accumulation density becomes larger, and the overall oil absorption of the product will be absorbed by oil. The amount will decrease.

For the application of high -quality products, magnesium hydroxide with high fineness and narrow granular distribution helps improve the performance of the product. At this time, the problem of oil absorption value is needed to solve the problem of oil absorption by surface modification.

3. Surface modification

Surface modification is one of the important means to effectively reduce the value of powder absorption. After the surface modification of magnesium hydroxide, the aggregate particles decrease, the dispersability is improved, and the gap between the particles is reduced. More closely, the accumulation density increases, and the oil absorption value decreases naturally.

The effect of variables of magnesium hydroxide production process on oil absorption value

1. The impact of secondary carbonization time

2. The impact of the amount of crystal control agent

Carbonized reactions include the production of magnesium hydroxide crystal nucleus and the grown up. In the early stage of carbonization reaction, with the increase of the amount of crystal control agent, the nuclear rate is greater than the growth rate. The surface area is large, the yield value is high, but the oil absorption value also increases accordingly.

3. The influence of the dosage of the surface active agent

As the amount of surface treatment agent increases, the oil absorption value of magnesium hydroxide continues to decline. However, when the amount of treatment agent is increased to a certain degree, the oil absorption value almost no longer decreases, and the excessive treatment agent in the system will cause the yield value to decrease.


From a micro perspective, the oil absorption value is related to the gap between the powder particles, the surface performance of the particles and the surface area of ​​the powder. When the nanoparticles are not modified, there is a gathering state, and the gap between the particles is large. At this time, the oil absorption value of the powder will increase.

The hydrophilic and oil performance of the particle surface has a great impact on the oil absorption value. After the powder is modified, the liquidity is increased, the surface can be reduced, the oil absorption value is reduced, and the dispersability is better. From another perspective, obtaining magnesium hydroxide with a smaller oil absorption value can greatly improve the decentralization of the particles and the parentability.

In addition, in the process of production of magnesium hydroxide, of course, the size of the particle size is first considered and the dispersion performance is first considered. On this basis, considering how to reduce its oil absorption value, only in this way can it have practical significance.

Magnesium hydroxide for coating
Magnesium hydroxide for coating

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