Preparation method for low-refractive-index high-transparency silicon dioxide

Abstract

The invention belongs to the technical field of silicon dioxide, and particularly relates to a preparation method for low-refractive-index high-transparency silicon dioxide. The preparation method comprises the following steps: S1, preparing a water glass solution, and performing standing and heat preservation to obtain a water glass sol seed crystal; S2, taking the water glass sol seed crystal, and adding water to dilute the water glass sol seed crystal and prepare a water glass base solution; S3, adding the water glass base solution and a sodium sulfate solution into a reaction kettle, and performing uniform stirring and heating; S4, simultaneously adding the water glass sol seed crystal and a sulfuric acid solution dropwise, controlling the pH in the process, and after addition of the water glass sol seed crystal is completed, continuing to add the sulfuric acid solution dropwise till the final pH; S5, stopping stirring, keeping the temperature, performing aging, and performing pressure filtration, washing, drying and crushing on formed silicon dioxide precipitates to obtain the silicon dioxide. The preparation method is simple, stable in process, low in production cost and less in pollution; the prepared silicon dioxide has high transparency under a low refractive index, and is applied to a transparent toothpaste formula, the using amount of water can be increased, and the using amount of a wetting agent is reduced, so that the production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of silicon dioxide, and in particular relates to a method for preparing low-refractive-index high-transparency silicon dioxide. Background technique [0002] In recent years, transparent toothpaste has become a familiar oral cleaning product. At present, silica is an essential raw material for making transparent toothpaste. It has good chemical stability and good compatibility with various additives, making silica toothpaste more and more competitive in the market. [0003] To make a transparent toothpaste, the refractive index of the liquid phase system and the solid phase system of the paste must be close to each other, or even consistent. The main components of the toothpaste liquid phase system are water and wetting agents, and sorbitol, polyethylene glycol and glycerin are commonly used wetting agents. Generally speaking, the refractive index of silica is in the range of 1.4300 to 1.4600, while that o...

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Problems solved by technology

[0005] In order to solve the problem of low transparency at low refractive index in the existing silica for toothpaste, the present invention provides a preparation method of low refractive index and high transparency silica, which can improve the low refractive index of silica. Transparency in the range of 1.4300-1.4400, so that it can reach more than 85%, and keep the transparency in the range of 1.4400-1.4600 of refractive index at more than 90%

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