Dimethyl silicone oil is widely used in many fields such as modern industry, medicine, and daily chemicals, and plays an indispensable role. However, according to different usage scenarios and needs, dimethyl silicone oil is divided into industrial grade and cosmetic grade, and there are many differences between the two.

From the definition and basic properties, dimethyl silicone oil is a polymer compound, and its chemical name is polydimethylsiloxane. It has the characteristics of being colorless and odorless, insoluble in water, methanol, vegetable oil and paraffin, slightly soluble in ethanol, butanol and glycerol, and easily soluble in benzene, toluene, xylene, ether and chloroalkanes. It has a small viscosity-temperature coefficient, a large compressibility, a small surface tension, good hydrophobicity and moisture resistance, small specific heat capacity and thermal conductivity, excellent electrical insulation and heat resistance, high flash point, low freezing point, and can be used for a long time in the temperature range of -50 to +200°C. However, industrial grade and cosmetic grade are significantly different in purity, impurity content, and subtle aspects of specific properties.

Industrial-grade dimethyl silicone oil is mainly used to meet various needs in the industrial production process. It is often used as a defoaming agent in the chemical, pharmaceutical and food industries. For example, in the fermentation process and food processing, it can effectively eliminate foam and ensure the smooth progress of production; in the molding process of plastics and rubber, it is an efficient release agent to help the product smoothly remove from the mold, improve production efficiency and product quality; in the electrical and electronic industries, it is used as a high-temperature resistant dielectric liquid to ensure the stable operation of electrical equipment in a high-temperature environment; in paints and other coatings, it is used as an additive to improve the performance of the coating. Industrial-grade dimethyl silicone oil usually has relatively low purity requirements, and cost control is more important. It may contain some impurities that are harmful to the human body or have adverse effects on the performance of cosmetics, such as heavy metals and aromatic hydrocarbons. Although these impurities have little effect in industrial applications, they are absolutely not allowed to exist in the cosmetics field.

Cosmetic-grade dimethyl silicone oil is specially produced to meet the strict requirements of cosmetic production and use. It is widely used in the cosmetics industry, such as hair oil, hair cream, hair styling agent, hair fixative and sunscreen. It has good lubricity and spreadability, can give the skin and hair a soft and smooth touch, and make the cosmetics more evenly and comfortable to apply. Cosmetic-grade dimethicone has extremely high requirements for safety, purity and stability. It must undergo a strict purification and testing process to ensure that it does not contain harmful impurities and meets national and international safety standards for cosmetic raw materials. For example, its heavy metal content must be controlled at an extremely low level to prevent irritation to the skin and potential health risks.

There are also significant differences in the production process. The production process of industrial-grade dimethicone is relatively simple, and the main goal is to meet the basic performance requirements of industrial applications and reduce production costs. Generally, dimethyldichlorosilane, water, and solvent are used as raw materials, and octamethylcyclotetrasiloxane is obtained by hydrolysis, neutralization, and fractionation, and then obtained by polymerization under the action of a catalyst. The production process of cosmetic-grade dimethicone is more delicate and complicated. In addition to the basic polymerization reaction, it is also necessary to go through multiple purification, filtration and other processes to remove possible impurities and harmful substances. During the production process, strict requirements are imposed on the cleanliness of the equipment and the sanitary conditions of the production environment to ensure the stability and safety of product quality.

In terms of quality standards and testing methods, industrial-grade dimethyl silicone oil mainly focuses on its performance indicators in industrial applications, such as viscosity, flash point, freezing point, electrical insulation performance, etc. The testing methods usually adopt industrial standard testing methods, such as measuring viscosity by viscometer and measuring flash point with flash point meter. In addition to testing these basic performance indicators, cosmetic-grade dimethyl silicone oil also needs to focus on testing its safety indicators. For example, advanced instrumental analysis methods are used to detect the content of heavy metals, and microbial testing is used to ensure that the product is free of microbial contamination. At the same time, cosmetic-grade dimethyl silicone oil also needs to undergo toxicological tests, such as skin irritation tests and acute toxicity tests, to ensure that it is harmless to human skin and health under normal use.

From the perspective of market application and price, industrial-grade dimethyl silicone oil is relatively cheap due to its wide application field, relatively low purity requirements, and large production scale. It is generally priced in kilograms. The price of common industrial-grade dimethyl silicone oil may be tens of yuan per kilogram. It is mainly used in all aspects of industrial production and provides important support for industrial development. Due to its strict quality requirements and complex production process, the price of cosmetic-grade dimethicone is relatively high. It is mainly used in the cosmetics industry to provide consumers with a safe and comfortable cosmetic experience. Its price may fluctuate according to different brands, quality grades, and market supply and demand conditions, usually at a price of several hundred yuan per kilogram or even higher.

Although both industrial-grade dimethicone and cosmetic-grade dimethicone belong to the dimethicone family, they are obviously different in definition, properties, production process, quality standards, testing methods, market applications, and prices. Understanding these differences is of great significance for related companies to correctly select and use dimethicone and ensure product quality and consumer health. At the same time, it will also help promote the continuous development and improvement of the dimethicone industry to meet the growing needs of different fields.