General Description

Silicone oil (high temperature) is a product in which some methyl groups in methyl silicone oil are replaced by phenyl groups. It has excellent electrical insulation properties, excellent ozone resistance, corona resistance, water and moisture resistance, and good chemical stability.[1] Silicone oil (high temperature) is one of the main products of silicone oil. Due to the introduction of phenyl groups, methylphenyl silicone oil has good heat resistance, chemical stability, electrical insulation, radiation resistance, etc., making methylbenzene Silicone-based oil has been widely used in many fields, especially in personal care, defense industry, aerospace, is a product with broad development prospects. Demand for methylphenyl silicone oil is increasing year by year, and research on its new varieties and new processes has become a hot spot in the silicone industry.[2]

Figure 1 Silicone oil (high temperature) Solution

Preparation

At present, there are two preparation methods for Silicone oil (high temperature). 

First preparation method:With Ph-D4 and D4 as monomer, the methylphenyl silicone oil was synthesized in following two ways:(I) The Ph-D4, D4 and tetramethyl ammonium hydroxide (TMAH) of silicone alkoxide were put into a four-neck flask at the same time, and then reacted at 90~100℃ and under vacuum. Initially the reactant appeared milky white, then it became clear and transparent and its viscosity became larger. After 8h, the reactant was heated to 150℃ at ambient pressure for 1h in order to decomposedthe catalyst. At last, low boiling matters in the reactant were removed under vacuum. (Ⅱ) Firstly, the certain amount Ph-D4 was put into four-neck flask, and being heated to 90℃ under stirring. The appropriate amount of TMAH of silicone alkoxide was also added to react at 90~100℃ under vacuum and D4 was added to the reactant when the viscosity increased. The catalyst was damaged at 150℃ at ambient pressure. And then the low boiling matters were removed at this temperature and under vacuum for 8h, and finally Silicone oil (high temperature) was obtained.[3] 

The Second synthetic method of the Silicone oil (high temperature) comprises the following steps of (1), mixing dimethoxymethylphenylsilane and divinyl tetramethyl disiloxane, rising temperature to 60 to 80 DEG C and performing stirring reaction, then adding an alkaline solution and performing reflux reaction, rising temperature to 100to 105 DGE C and performing reduced pressure reaction, rising temperature again to 108 to 112 DGE C for reaction and performing drying; (2), filtering a silicone oil product obtained in the step (1),adding low alcohol for washing, after layering, removing alcohol layer, performing reduced pressure distillation on silicone oil layer for removing solvent low alcohol, thus obtaining the Silicone oil (high temperature).The Silicone oil (high temperature) with high refraction is synthesized by using a one-step method, an organic solvent is not needed to add in the reaction process. The silicone oil obtained by the method has narrow molecular weight distribution, high quality, good stability and proper viscosity, the refractive index and luminous flux of packaging adhesive are effectively improved by using the synthetic method as a formula.[4]

Main Application

The application range of Silicone oil (high temperature) is very wide. It is not only used as a special material for aviation, cutting-edge technology, and military technology, but also used in various sectors of the national economy. Its application range has been expanded to: construction, electronic and electrical, textiles, automobiles, machinery, leather and paper, chemical and light industry, Metal and paint, medicine and medical treatment, etc.[5]

Use of silicone oil in the field of methyl silicone oil, can play its low temperature, high temperature, lubricity, compatibility characteristics. Low phenyl silicone oil is particularly suitable for applications requiring a high degree of cold; medium and high phenyl silicone oil high thermal stability, good radiation resistance, can be used for metal products, heat treatment bath, high temperature heating oil, gas chromatography High temperature lubricating oil for carrier, electronic and electric equipment. High temperature grease made of carbon black, lithium soap or molybdenum disulfide can be used for lubrication of high temperature fan bearings, ball bearings, automobile engines, textile dryers and the like.[6] Additionally, Silicone oil (high temperature) can be used as sealing agent for growing protein crystal.[7]

Reference

[1]You M, Li Z, Yang H. Silicone oil (high temperature) with high boiling point and preparation method[P].CN111978544,2020.11.24

[2]Yin H, Ma K. Preparation method of high-refraction index Silicone oil (high temperature).[P].CN103408759, 2013.11.27.

[3]Dong YR, Wang JR, Guan RF, et al. Preparation and Characterization of Metheylphenyl Silicone Oil for Buffer Clay[C]//Advanced Materials Research. Trans Tech Publications Ltd, 2011, 197: 1188-1191.

[4]Qiu M, Feng L, Luan A. Synthetic method of Silicone oil (high temperature) with high refractive index.[P]. CN108329475, 2018.7.27.

[5]Shi P, Gan F, Xue C, et al. A kind of Silicone oil (high temperature) for processing of high-efficiency filtration device.[P].CN213376604, 2021.6.8.

[6]Wang Y, Zhang X. Preparation method of adsorbent for Silicone oil (high temperature)[P].CN107233862,2017.10.10.

[7] Chen M. Method for growing protein crystal by using methyl silicone oil or Silicone oil (high temperature) as sealing agent[P].CN1727528,2016.2.1.