Fumed silica is a kind of colorless, tasteless and nontoxic nano amorphous silica, which is produced by the hydrolysis of halosilane in the oxyhydrogen flame at high temperature to produce silica particles, and then quenched suddenly. The particles are processed by aggregation, separation, deacidification and so on. It has the characteristics of small particles, uniform particle size distribution and large specific surface area, so it has high surface activity.
Total reaction formula: 2h2 + O2 + SiCl4 → SiO2 + 4 HCl
A simple model of particle generation in flame (source: Degussa)
Note: the silica aggregate is a kind of silica agglomerate formed by the fusion of many particles, which has irregular properties and is mainly branched chain, while the aggregate is a kind of silica agglomerate formed by the attraction of hydrogen bond and van der Waals force. The agglomerates are unstable, easy to separate after being stressed, and easy to agglomerate again after being eliminated. However, the agglomerates are stable, which is generally believed not to be easily damaged.
The ultra light solid form and various unusual interesting properties of fumed silica provide unlimited possibilities for its application in the field of personal care. Generally speaking, adding fumed silica to the formula in the field of personal care can thicken the product, improve the stability of the product, improve the thixotropic performance of the product and the skin feeling when using, etc., which will be briefly described below.
Silica for make-up
Fumed silica is an efficient anti caking agent and free flowing agent, which can effectively improve the storage stability of cosmetics and the dispersibility of powder products. Therefore, it can be seen in foundation, honey powder, eye shadow, eyebrow powder and eyeliner.
Fumed silica can not only effectively improve the fluidity of powder, but also prevent the re aggregation of pigment, so it is often used in cosmetic products with high pigment content. For example, adding lipstick can make the pigment evenly distributed in lipstick and prevent the pigment from transferring or embedding into the fine lines of the lips.
Silica for hair care
As soon as the hair collapses, it shows a big face. Miss and sister become aunts and handsome men become uncles. The hair volume is small. The extremely small and soft hair affects the human face value. It's not easy to have hair, but it's easy to keep it fluffy. The hair care products added with fumed silica, the fumed silica in the product attached to the hair to enhance the fluffy degree of the hair after shampoo, so as to achieve the effect of increasing the hair volume visually, which is actually the gospel of rare star people.
When your hair collapses, your face will be big
Application example of conditioner: hydrophilic fumed silica and quaternary ammonium compound can counteract the flattening effect of conditioner on hair (hair collapses), which has a good effect on improving the combing and fullness of hair (usually the amount added is between 1.0% and 2.0%).
Silica for skin care products
In oil-based products such as ointment, gel, cream and so on, adding hydrophilic fumed silica can significantly increase thickening products and increase the stability and thixotropy of products. According to a product introduction, when the concentration reaches 3%, it can obviously reduce the oily skin feeling of skin care products.
In W/O emulsion products, hydrophobic gas phase silica can be used to increase product consistency and reduce the greasy feeling of products.
With it, skin care products won't stick anymore~
Silica for sun protection products
At present, sunscreen products mainly use physical sunscreen and chemical sunscreen, such as titanium dioxide, zinc oxide and other physical sunscreen and methoxycinnamate isooctyl ester and other chemical sunscreen. The advantage of chemical sunscreen is that it can be dissolved in the oil phase, and the product is fine in texture and light in muscle. The disadvantage is that it will decompose slowly under the effect of ultraviolet rays, and the sunscreen effect will become worse. In order to ensure the sunscreen effect, more sunscreen agents are often needed, but excessive sunscreen agents can potentially harm the skin. The biggest point of physical sunscreen is that it is inert, not photodegradable, and does not have the problem of skin absorption, but its disadvantages are also very obvious: sunscreen particles are easy to agglomerate and deposit, the use of skin is poor, and it is difficult to spread evenly on the skin.
Silica used in antiperspirant products
Fumed silica is widely used in the suspension stabilizer of antiperspirant spray, antiperspirant bead and antiperspirant stick. It can effectively prevent the accumulation of effective components of "antiperspirant" and make it evenly distributed and durable.
In addition, compared with other suspending agents, the high transparency of fumed silica can minimize the pollution of antiperspirant on dark clothes and reduce embarrassment.
Maybe antiperspirant can save this embarrassing summer
Powder circle Author: Xiaobai
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