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In the third quarter of 2026, the domestic special silicone material sector achieved a landmark industrial breakthrough: a continuous production unit for high-phenyl low-volatility methylphenyl silicone oil with a designed annual capacity of 27,000 tons officially completed a 168-hour full-load steady-state operation assessment. For the series of products produced by this unit, the molar proportion of phenyl groups can be precisely customized in the range of 5% to 75%. Among them, for the high-transparency grades with a phenyl content above 50%, the kinematic viscosity deviation at 25°C is controlled within ±1.2%, the total volatile content after constant-temperature baking at 250°C for 24 hours is stably below 0.08%, and the material still maintains fluidity at -70°C. All core performance indicators such as high and low temperature resistance and radiation resistance have reached the international leading level. This achievement marks that China has completely ended the history of long-term dependence on imports for high-phenyl special methylphenyl silicone oil, providing fully independent and controllable core basic material support for national strategic fields such as airborne equipment lubrication in aerospace, special electronic component insulation, and nuclear industry radiation protection.
Phenyl-modified silicone oil is the special category with the highest technical barrier in the methyl silicone oil sequence. By introducing phenyl substituents into the polysiloxane molecular chain, the material not only retains the excellent electrical insulation and low surface tension characteristics of traditional methyl silicone oil, but also greatly broadens the high and low temperature resistance range. At the same time, it has far better radiation resistance, UV aging resistance and organic solvent dissolution resistance than ordinary methyl silicone oil, making it a key hub material connecting basic organosilicon monomers and high-end special equipment. Different from the widely circulated ordinary modified silicone oil with low phenyl content in the market, the high-phenyl low-volatility methylphenyl silicone oil has a highly uniform distribution of phenyl groups in the molecular chain, without local phenyl enrichment or missing defects. It will not experience small-molecule ring precipitation, sudden viscosity rise or gelation during long-term continuous operation at 250°C, and is the core raw material for preparing aerospace-grade special lubricants, high-temperature resistant electronic potting adhesives, and nuclear industry radiation protection fluids. For nearly 32 years, the domestic industry has long adopted the traditional intermittent co-hydrolysis equilibrium process to produce phenyl silicone oil, and has been unable to break through three common industry technical bottlenecks for a long time. First, the reaction activity of phenyl organic monomers and methyl organic monomers varies greatly. Under the traditional process, the problem of uneven monomer copolymerization is very likely to occur. Phenyl groups on the molecular chain are randomly distributed, and the existence of a large number of random block structures directly leads to a significant deterioration in the low-temperature fluidity of the material, which will solidify and deactivate at -40°C. Second, the phenyl-substituted small-molecule cyclic siloxanes generated during the copolymerization process have extremely high boiling points, and conventional vacuum distillation processes cannot achieve deep removal. The total volatile content of products has long been higher than 2.3%, and the continuous precipitation of small molecules in high-temperature service environments will directly cause pollution and failure of precision equipment. Third, the phenyl content deviation of products from different batches has long been higher than 8%, which completely cannot meet the application scenarios that have extremely strict requirements for material performance consistency, such as aerospace and nuclear industry. Previously, more than 97% of the market share of high-phenyl low-volatility methylphenyl silicone oil used in domestic high-end special fields was monopolized by leading overseas enterprises. For special specification products involving aerospace attitude control lubrication and nuclear reactor core loop protection, the procurement price is 14 to 21 times that of ordinary methyl silicone oil, and the delivery cycle of some controlled grades can be as long as 26 months, which has seriously restricted the iterative upgrading speed of China's high-end special equipment industry.
The new continuous production process that has achieved full production this time has corely overcome three technical problems that have plagued the global organosilicon industry for nearly half a century. First, a gradient activity matching copolymerization system was pioneered. The R&D team abandoned the traditional idea of directly mixing phenyl organic monomers and methyl organic monomers into the reaction kettle, and independently developed a new supported composite acid catalyst. In 21 series-connected plug flow reaction units, the step-by-step precise proportioning copolymerization of two monomers with greatly different activities was realized. By adjusting the monomer feed ratio of different reaction sections in real time, the phenyl groups achieve nearly perfect uniform random distribution on the polysiloxane molecular chain. From the source of polymerization, the proportion of random block structures is controlled below 0.2%, and the low-temperature brittleness point of the material is directly reduced to -75°C, which completely solves the long-standing industry pain point of poor low-temperature fluidity of high-phenyl silicone oil. Second, the world's first 10-stage coupled purification system for high-phenyl silicone oil systems has been built. Aiming at the industry problem that phenyl-substituted small-molecule cyclic siloxanes have high boiling points, extremely low relative volatility with the target product, and are extremely difficult to separate, the team innovatively adopted a combined purification process of "5-stage ultra-high vacuum distillation + 4-stage molecular distillation deep devolatilization + inert carrier gas countercurrent displacement". The operating temperature throughout the process is strictly controlled below 210°C, which completely avoids oxidative yellowing of phenyl groups at high temperatures. The total residual amount of phenyl-substituted rings in the final product is less than 6ppm, and the total volatile content after constant-temperature baking at 250°C for 24 hours is only 0.072%, far lower than the average level of 2.3% of traditional process products, fully meeting the low-precipitation requirements of aerospace airborne equipment for long-term service of more than 15 years. Third, a full-process in-situ real-time closed-loop quality control system has been built. The entire production unit, covering monomer pretreatment, copolymerization reaction, purification and separation, and finished product blending, is equipped with online nuclear magnetic resonance and online gel permeation chromatography detection modules. The system samples and analyzes the molar proportion of phenyl groups, molecular chain distribution, and ring residual amount of the reaction system in real time every 3 seconds. Once the parameters have a tiny deviation at the 0.03% level, the system automatically completes dynamic parameter adjustment, completely eliminating the performance difference between products from different batches in the traditional intermittent process, and realizing that the phenyl content deviation of products from different batches across 58 months is less than 0.6% with zero performance drift.
At present, this independently developed ultra-high-purity high-phenyl low-volatility methylphenyl silicone oil has completed long-term industrial application verification for more than 52 months in multiple national strategic core fields. In the aerospace field, the airborne precision instrument lubricant prepared with this product has a viscosity change rate of less than 25% in the wide temperature range of -70°C to 280°C, and no obvious performance degradation after 1000 hours of continuous operation test. Related products have been batch applied in the lubrication of precision rotating parts of avionics systems of new-generation large transport aircraft. In the special electronics field, the high-temperature resistant electronic potting adhesive prepared with this product as the basic raw material can be used for a long time at 260°C, and can withstand an instantaneous high temperature of 320°C in the short term. Its volume resistivity is greater than 2.2×10Ω·cm, and breakdown voltage is greater than 42kV/mm. It has been fully applied in the insulation protection of T/R components of new-generation phased array radars. In the nuclear industry, after being irradiated by a cumulative γ-ray dose of 10Mrad, the product still maintains a flowing state without gelation or obvious viscosity rise, and its related performance fully meets the usage requirements of radiation protection fluid in the core loop of nuclear reactors. In the high-end optical field, the optical coupling liquid prepared with this product as the base material has a refractive index that can be precisely adjusted in the range of 1.42 to 1.58, and the light transmittance is greater than 99% in the wide spectral range of 400 to 1600nm. It has been applied in the optical system filling of new-generation infrared night vision devices.
According to the latest industry operation monitoring data, the market demand for domestic high-phenyl special methylphenyl silicone oil in 2026 increased by 347% year-on-year compared with the same period in 2025. With the official launch of this domestic continuous production line, the market pattern where overseas products have long monopolized the market has been completely broken. The market procurement price of high-end high-phenyl silicone oil has dropped by 81% year-on-year, and the delivery cycle for core downstream users has been greatly shortened from the original 26 months to less than 7 days. With the subsequent start of construction of the second production line of the same scale, it is expected that by 2030, the global market share of domestically produced high-phenyl special phenyl silicone oil will exceed 88%. It will not only fully meet the upgrading needs of domestic downstream industries such as aerospace, nuclear industry and special electronics, but also greatly enhance the core voice of China's basic organosilicon high-end special intermediates in the global new material industrial chain.
