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In the fourth quarter of 2026, the domestic high-end phenyl modified silicone oil industrialization process achieved a milestone progress: a full-spectrum electronic-grade phenyl modified silicone oil continuous production unit with a designed annual capacity of 28,000 tons officially completed a 168-hour full-load steady-state operation assessment and realized large-scale mass production and delivery. The series of phenyl modified silicone oil products produced by this unit cover a phenyl molar content range of 5% to 55%, the refractive index can be precisely adjusted between 1.46 and 1.57, and the kinematic viscosity extends from 5mm²/s to 80000mm²/s. Among them, the high refractive index optical grade for high-power LED chip packaging has a refractive index reaching 1.567, a transmittance in the visible light region (380-780nm) greater than 99.2%, a yellowing index ΔYI of less than 0.08 after 200°C/1000 hours, and no crystal precipitation at -60°C environment. All core performance indicators have reached the international leading level. This achievement marks that China has completely broken the 35-year technological monopoly of overseas enterprises on high-end phenyl modified silicone oil, providing fully independent and controllable core basic material support for key national fields such as semiconductor advanced packaging, optical communication device packaging, and extreme environment optical protection for aerospace.
Phenyl modified silicone oil is a type of special modified silicone oil formed by introducing phenyl groups into the molecular side chain of polysiloxane. By replacing part of the methyl groups of traditional methyl silicone oil with phenyl groups, the comprehensive properties of the material such as optical refractive index, high and low temperature resistance, radiation resistance and solvent resistance are greatly improved at the molecular level. Compared with ordinary methyl silicone oil, the refractive index of phenyl modified silicone oil can be increased to 1.46~1.57, while combining the weatherability, heat resistance and electrical insulation characteristics of organosilicon materials with the advantages of radiation resistance, chemical corrosion resistance, solvent extraction resistance and high temperature stability brought by the phenyl structure. It is a special optical and sealing basic raw material that cannot be replaced by other organosilicon or organofluorine materials. In the field of high-power LED chip packaging, traditional epoxy resin packaging materials are prone to yellowing and transmittance attenuation under high temperature and high humidity environments, and methyl silicone oil has too low refractive index to meet the high light extraction efficiency requirements. In contrast, high refractive index phenyl modified silicone oil, with its excellent optical performance and long-term thermal stability, has become the mainstream optical potting adhesive matrix material for COB packaging and flip-chip packaging. In the field of optical communication device packaging, phenyl modified silicone oil, as a key sealing and potting material for optical fiber connectors, wavelength division multiplexers and optical modules, can maintain stable optical transmittance and mechanical strength in a wide temperature range of -60°C to 250°C, fully meeting the reliability requirements of 5G/6G base station equipment for long-term outdoor extreme working conditions. In the aerospace field, the high-temperature resistant sealing grease prepared from phenyl modified silicone oil can work stably for a long time in high temperature above 300°C and strong oxidation environments, while tolerating high-energy ray irradiation. It has been widely used in the long-term lubrication and sealing of satellite solar panel drive mechanisms and aero-engine high-temperature accessories.
Over the past three decades, the domestic phenyl modified silicone oil industry has long stayed in the stage of medium and low-end, small-batch production, and has been unable to break through three common industry technical bottlenecks. The first is the problem of directional and controllable introduction of phenyl groups: the hydrolysis and polycondensation reaction activity difference between phenyl chlorosilane monomers and methyl chlorosilane is huge. Under the traditional batch co-hydrolysis process, problems such as uneven distribution of phenyl groups and low degree of random copolymerization are very likely to occur. A large number of random segments with local phenyl enrichment or deficiency directly lead to unstable refractive index and poor low-temperature crystallization resistance of the product. The refractive index fluctuation range of phenyl modified silicone oil produced by domestic traditional processes has long been higher than ±0.03, and it is prone to phenyl crystal precipitation at environments below -40°C, which completely cannot meet the stability requirements of optical communication devices for long-term service at -60°C. The second is the problem of high temperature thermal stability and yellowing resistance: phenyl groups are prone to thermal oxidative crosslinking under high temperature oxidation environments, leading to material yellowing and transmittance decline. The 200°C/1000 hours yellowing index ΔYI of domestic traditional products is generally greater than 0.35, and the optical performance decays seriously after long-term service, which cannot meet the light efficiency maintenance rate requirement of high-power LED chips for more than 100,000 hours. The third is the problem of preparing ultra-high purity electronic-grade products: trace chlorine ions, metal ions and phenyl ring oxidation by-products remaining during the synthesis of phenyl silicone oil can easily cause device corrosion and optical path pollution in high-cleanliness scenarios such as semiconductor packaging and optical communication. The total residual amount of metal ions in domestic traditional products is generally higher than 50ppb, and the chlorine ion content exceeds 10ppm, which completely cannot meet the stringent standards of electronic-grade packaging materials. Previously, high-quality phenyl modified silicone oil used in domestic high-end fields has long been monopolized by leading overseas enterprises. The purchase price of high refractive index optical grade is 18 to 25 times that of ordinary methyl silicone oil, and the delivery cycle of some customized aerospace specifications can be as long as 24 months, which has seriously restricted the independent development process of China's high-end optoelectronic packaging, aerospace optical protection and other industries.
The new continuous production system that has achieved full production this time has corely overcome three technical barriers that have plagued the global phenyl modified silicone oil industry for more than thirty years. First, the controllable gradient copolymerization technology of phenyl groups was pioneered. The R&D team abandoned the traditional idea of directly mixing phenyl chlorosilane and methyl chlorosilane for hydrolysis, and independently developed a solid-supported phenyl directional catalytic system. In 28 series-connected plug flow reaction units, the feeding ratio and reaction temperature of phenyl monomers are dynamically regulated according to the monomer conversion rate of different reaction sections, so that phenyl groups achieve nearly perfect uniform random distribution on the polysiloxane molecular chain. From the source of polymerization, the proportion of random segments with uneven phenyl distribution is controlled below 0.08%. The refractive index fluctuation range of the final product is less than ±0.005, and there is no crystal precipitation after continuous testing for 1000 hours at -60°C environment. The low-temperature stability has reached the world's top level. Second, the world's first 16-stage coupled purification and stabilization system for phenyl silicone oil systems has been built. Aiming at the industry pain point that phenyl oxidation by-products have high boiling points and poor thermal stability, the team innovatively adopted a combined process of "8-stage ultra-high vacuum distillation + 7-stage molecular distillation deep devolatilization + supercritical inert fluid in-situ stabilization". The operating temperature throughout the process is strictly controlled below 190°C, which completely avoids the oxidative crosslinking of phenyl groups at high temperatures. The residual amount of phenyl ring oxidation by-products in the final product is less than 2ppm, and the yellowing index ΔYI at 200°C/1000 hours is only 0.075, far lower than the average level of 0.35 of traditional processes, fully meeting the long-term service requirements of high-power LED chips for 100,000 hours of light efficiency maintenance rate. Third, a full-process in-situ real-time closed-loop quality control system has been built. The entire unit, covering monomer pretreatment, copolymerization reaction, purification and separation, and finished product blending, is equipped with online UV-Vis spectroscopy and online inductively coupled plasma mass spectrometry detection modules. The system samples and analyzes the phenyl molar content, refractive index and trace metal ions of the reaction system in real time every 1.8 seconds. Once the parameters have a tiny deviation at the 0.008% level, the system automatically completes dynamic parameter adjustment, completely eliminating the batch performance difference of the traditional batch process, realizing that the refractive index deviation of products from different batches across 68 months is less than ±0.003 with zero performance drift, and can stably produce full-spectrum products with phenyl molar content of 5%~55%, refractive index of 1.46~1.57, and viscosity of 5mm²/s~80000mm²/s.
At present, this independently developed full-spectrum electronic-grade phenyl modified silicone oil has completed long-term industrial application verification for more than 60 months in multiple national strategic core fields. In the field of semiconductor advanced packaging, the high refractive index optical potting adhesive prepared with this product has a refractive index of 1.567 and a visible light transmittance greater than 99.2%. After 5000 hours of 85°C/85%RH double 85 aging test, the yellowing index ΔYI is less than 0.12. Related products have been batch applied to the COB packaging production line of new-generation Mini/Micro LED chips. In the field of optical communication device packaging, the optical fiber connector sealant prepared with this product as the core has an insertion loss change of less than 0.05dB in the temperature cycle test of -60°C to 150°C, and no cracking or debonding after 1000 thermal shocks. It has been fully applied to the large-scale production of 5G/6G base station optical modules. In the aerospace field, the high-temperature resistant sealing grease prepared from this product has a mass loss rate of less than 0.18% after continuous operation for 1000 hours in high-temperature air at 300°C, no hardening and no loss, which fully meets the long-term lubrication and sealing requirements of the new generation of satellite solar panel drive mechanisms for 15 years in orbit. In the field of special coatings, medium phenyl content modified silicone oil, as a leveling agent and toughening agent for high-temperature resistant coatings, can maintain the flexibility and adhesion of the coating for a long time at high temperatures up to 500°C. Related raw materials have been applied to the formula system of protective coatings for aero-engine hot end components. In the field of personal care, low phenyl content modified silicone oil, with its excellent high temperature and radiation resistance, can be used as a heat protection component of high-end hair care products, and can maintain hair gloss and softness at hair styling temperatures of 200°C. Related raw materials have been applied to the formula development of high-end professional hair care products.
According to the latest industry operation monitoring data, the market demand for domestic high-quality phenyl modified silicone oil in 2026 increased by 385% 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 purchase price of electronic-grade phenyl modified silicone oil has dropped by 81% year-on-year, and the delivery cycle for core downstream users has been greatly shortened from the original 24 months to less than 4 days. With the subsequent start of construction of the second production line of the same scale, it is expected that by 2031, the global market share of domestically produced high-quality phenyl modified silicone oil will exceed 89%. It will not only fully meet the upgrading needs of domestic downstream industries such as high-end optoelectronic packaging, optical communication devices and aerospace, but also greatly enhance the core voice of China's high-end phenyl modified silicone oil special intermediates in the global new material industrial chain, providing key material support for the development of global optoelectronic industry, aerospace and related fields.
