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In the third quarter of 2026, a landmark industrial progress in China's organosilicon special intermediate sector was officially announced: the new generation full-series production line of hydroxyl silicone oil, covering three major categories of low-viscosity electronic grade, medium-viscosity new energy grade and high-viscosity aerospace grade, has officially passed the batch application verification of leading users in multiple downstream fields and achieved continuous, stable and full-load operation. Core performance indicators including hydroxyl content control accuracy, low-molecular cyclic residue and molecular weight distribution uniformity have fully reached the international top level, and some performance parameters under extreme working conditions have surpassed overseas counterparts, completely ending the nearly 40-year technological monopoly of overseas enterprises in the field of high-end special hydroxyl silicone oil. As a core functional intermediate connecting the upstream and downstream of the organosilicon industrial chain, hydroxyl silicone oil, with reactive hydroxyl groups at both ends of its molecular chains, is a key basic raw material for hundreds of downstream products such as addition-cured silicone rubber, silicone sealant, organosilicon modified resin and functional fabric finishing agent, widely supporting dozens of core fields related to the national economy and people's livelihood including new energy power batteries, aerospace composite materials, nuclear power equipment sealing and medical implant consumables. The implementation of this full-series special production capacity marks that the independent controllability of China's entire organosilicon industrial chain has completed a key upgrading of supplementing and strengthening the industrial chain.
Looking back at the development context of China's hydroxyl silicone oil industry, the evolution of the past 40+ years has always been driven by the demand pressure from downstream high-end manufacturing upgrading and continuous R&D efforts at the scientific research end. As early as the 1980s, China realized small-batch production of general-purpose hydroxyl silicone oil with viscosity below 100mm²/s. However, restricted by core technical shortcomings such as precise regulation of active groups in ring siloxane ring-opening polymerization, deep removal of low-molecular cyclic bodies and narrow molecular weight distribution polymerization, domestic products have long been concentrated in low-to-medium end scenarios such as ordinary rubber modification and civil fabric softeners. Persistent industry pain points, including hydroxyl content fluctuation exceeding 15%, small molecule volatile matter higher than 3% and poor batch-to-batch performance consistency, have never been completely solved, making it impossible to meet the strict requirements of extreme working conditions in new energy, aerospace and other fields. For a long period, the import dependence of China's special hydroxyl silicone oil with viscosity higher than 10000mm²/s and volatile content lower than 0.1% exceeded 88%. Overseas suppliers not only maintained high pricing for a long time, the price of some high-end grades was even 5-8 times that of ordinary domestic products, but also frequently restricted supply by imposing export controls, setting up technical barriers and extending delivery cycles, bringing great supply chain risks to the stable production of multiple strategically emerging industries in China. In 2022, a new energy industrial cluster in China was forced to temporarily reduce production of downstream power battery sealant production lines due to the supply interruption of overseas special hydroxyl silicone oil, resulting in direct economic losses of more than 100 million yuan, highlighting the hidden dangers of supply chain security.
Since 2023, the explosive growth of downstream emerging industries has directly driven the demand expansion of the hydroxyl silicone oil market. Authoritative industry statistics show that in 2024, the overall market size of hydroxyl silicone oil in China reached 14.7 billion yuan, with a total output exceeding 132,000 tons, a year-on-year increase of 25.1%. Among them, special hydroxyl silicone oil with high viscosity and low volatility contributed more than 79% of the incremental demand. From the perspective of downstream demand structure, 39.4% of China's hydroxyl silicone oil demand comes from the new energy power battery sealing and potting field, 23.1% comes from the high-end building and transportation equipment sealant scenarios, 12.8% comes from the aerospace and nuclear power equipment special material field, and the remaining demand is distributed in segmented tracks such as medical silicone rubber consumables, precision electronic insulating coatings and high-end fabric functional finishing. With the continuous large-scale delivery of China's new energy vehicle industry, the production and sales of new energy vehicles in China exceeded 12 million units in 2024, and the corresponding demand for power battery sealing materials increased by 41% year-on-year. At the same time, with the comprehensive construction of large-scale wind power bases, the mass implementation of third-generation nuclear power technology and the large-scale delivery of commercial large aircraft, the demand growth rate for high-end hydroxyl silicone oil has remained above 33% for three consecutive years. Traditional low-to-medium end products have been completely unable to match the performance requirements of downstream extreme working conditions, making the full-process technological upgrading at the industrial end extremely urgent.
The core technological breakthroughs of this new generation of full-series production line cover the full chain links from raw material pretreatment to finished product post-treatment. On the raw material side, the new continuous distillation coupled with molecular sieve deep adsorption purification process increases the purity of polymerization monomers such as octamethylcyclotetrasiloxane (D4) to 99.985%, controlling the moisture, chloride ion and metal ion impurities in the raw material below 8ppm, 3ppm and 12ppb respectively, avoiding the problems of runaway polymerization reaction, premature end-capping of hydroxyl groups and later product thermal stability decline caused by impurities from the source. In the polymerization reaction stage, the independently developed gradient heating controllable living anionic ring-opening polymerization technology realizes 100% precise positioning of hydroxyl groups at both ends of the siloxane molecular chain, no side-chain hydroxyl by-products are generated, making the hydroxyl content control accuracy of products 63% higher than that of the traditional batch process, and the molecular weight distribution index is controlled below 1.1, far lower than the industry average of 1.6 in traditional processes, completely solving the long-standing industry pain point of "large performance fluctuation of downstream products and poor aging resistance caused by excessively wide molecular weight distribution". In the post-treatment link, the application of the 10-stage high-vacuum multi-stage thin-film evaporation coupled with supercritical CO₂ extraction deep devolatilization system controls the small molecule cyclic volatile content of the product below 0.07%, far lower than the industry average of 3.2% in traditional processes, even better than the 0.1% control standard of overseas top-tier similar products, completely solving the long-standing industry problem of high-end downstream equipment that silicone oil is prone to precipitate small molecules under high-temperature working conditions, leading to seal failure and poor contact of electronic components. At the same time, the new recyclable weak alkaline solid catalytic system replaces the traditional strong acid and strong alkali catalysts, reducing the waste catalyst discharge in the production process by 97.5%, the energy consumption per unit product by 52%, and the organic waste gas emission in the production process by 92%. While greatly improving product quality, it also achieves the industrial upgrading goal of green and low-carbon production, fully meeting the upgrading requirements of the domestic chemical industry under the "dual carbon" goal.
The most direct value brought by technological upgrading is the performance breakthrough in core downstream application scenarios. In the new energy power battery field, the power battery silicone rubber sealing gasket prepared with the new generation of low-volatility hydroxyl silicone oil maintains stable sealing performance in the wide temperature range of -45℃ to 190℃, and the compression set rate after 3500 cycles of long-term service is controlled within 5.2%. After 1000 hours of high-temperature and high-humidity aging test, the sealing performance retention rate exceeds 96%, fully meeting the waterproof, insulating and leakage-proof requirements of the power battery throughout its life cycle. Even in the initial stage of power battery thermal runaway, the sealing gasket can maintain a complete structure, delaying the leakage speed of flue gas and greatly improving the safety performance of the power battery. Previously, the core raw material of this high-end sealing material was completely dependent on imports. The implementation of domestic products directly reduces the comprehensive production cost of China's new energy power battery sealing system by 32%, further consolidating the global competitive advantage of China's new energy vehicle industry. In the polyurethane modified coating for wind turbine blades, after adding medium-viscosity hydroxyl silicone oil as a modifier, the surface energy of the coating is reduced to 22mN/m, the weather resistance is increased by 47%, and the service life in the coastal high salt spray and strong ultraviolet environment is extended from 8 years to 22 years, greatly reducing the later maintenance cost of wind power equipment and improving the full-life-cycle power generation efficiency of wind power equipment.
In the field of construction and transportation equipment, the high-end silicone structural sealant prepared from high-viscosity hydroxyl silicone oil maintains stable bonding strength in the temperature range of -65℃ to 230℃, the bonding strength to various substrates such as aluminum alloy, glass and carbon fiber composite materials exceeds 2.5MPa, and the attenuation rate of bonding strength does not exceed 11% after 3500 hours of ultraviolet aging test. It has now been batch applied in the sealing systems of multiple super high-rise landmark buildings, high-speed rail carriages and sea-crossing bridges in China, completely solving the long-standing "stuck neck" problem of core material supply chain that plagues China's high-end building sealing industry. In the aerospace field, the specially modified high-purity hydroxyl silicone oil is added to the carbon fiber epoxy resin system as a toughening agent, the interlaminar shear strength of the composite material is increased by 28%, and the impact toughness is increased by 42%, greatly improving the fatigue resistance of aerospace structural parts and extending the service life of structural parts. In the field of nuclear power equipment, the seal gasket prepared from nuclear-grade purified hydroxyl silicone oil has a performance retention rate of more than 90% after long-term service in a strong radiation environment, fully meeting the sealing requirements of the primary loop auxiliary equipment of third-generation nuclear power units, and has been batch applied in multiple newly built third-generation nuclear power units in China.
In the field of medical consumables, the medical-grade hydroxyl silicone oil after special multi-stage purification has a small molecule cyclic dissolution far lower than the requirements of the ISO 10993 medical material standard. The prepared implant-grade silicone rubber has a biocompatibility up to the highest Class VI standard, and has been successfully applied in high-end medical consumables such as artificial soft tissue repair, medical catheters and implantable drug delivery devices, greatly improving the safety of domestic high-end medical silicone rubber products, reducing the production cost of high-end medical consumables, and allowing more patients to use cost-effective domestic medical consumables. In the field of precision electronics, the electronic-grade insulating potting material prepared from electronic-grade low-viscosity hydroxyl silicone oil maintains stable insulating performance in high-voltage and high-humidity environments, with a volume resistivity exceeding 1×10¹⁶Ω·cm, effectively avoiding the short-circuit risk of precision electronic components, and providing reliable insulation and heat dissipation guarantee for the core computing chips of 5G communication base stations, high-end servers and artificial intelligence computing centers.
With the gradual release of domestic high-end production capacity, the market supply structure of hydroxyl silicone oil is undergoing fundamental changes. In the past two years, China's hydroxyl silicone oil industry has gradually bid farewell to the extensive low-end capacity expansion model. A large number of small and medium-sized production capacities with substandard environmental protection and backward technical levels have exited in an orderly manner. The industry concentration has continued to increase, and resources are accelerating to gather in leading enterprises with full-chain R&D strength. In 2025, the market size of hydroxyl silicone oil in China is expected to exceed 18 billion yuan, among which the market share of special high-end hydroxyl silicone oil will further increase to 48%, and the localization rate of high-end products is expected to exceed 68% by the end of the year. At the global market level, the global hydroxyl silicone oil market size is about 950 million US dollars in 2025, and it is expected to grow to 1.82 billion US dollars at a compound annual growth rate of 9.5% from 2025 to 2032. As the world's largest emerging market for hydroxyl silicone oil, China is gradually shifting from product import to independent supply and technology output, occupying a more core position in the global organosilicon new material industrial chain. Some domestic high-end hydroxyl silicone oil products have begun to be exported to Europe, Southeast Asia and other markets in batches, and have been recognized by overseas users with their excellent performance and stable supply capacity.
Industry experts point out that the full-series technological breakthrough and capacity implementation of high-end hydroxyl silicone oil is a landmark event for China's organosilicon new material industry to shift from "general-purpose scale leadership" to "full-chain independent control of key intermediates". In the past, China's organosilicon industry long focused on the scale expansion of downstream end products such as dimethyl silicone oil and 107 glue, and was restricted by others in the field of high-end special hydroxyl silicone oil, a key intermediate connecting the upstream and downstream, for a long time. The full-process independent control of technology this time not only directly reduces the production cost of dozens of downstream high-end organosilicon new materials, but also opens up the full industrial chain technical barriers from basic chlorosilane monomers and cyclic siloxanes to high-end end products, opening up a new space for subsequent innovation of the entire industry. In the future, with the continuous iteration of downstream emerging industries, high-end hydroxyl silicone oil will also achieve application breakthroughs in more cutting-edge scenarios such as solid-state battery electrolyte modification, insulating medium toughening for controllable nuclear fusion devices and flexible electronic substrate modification, providing solid material support for the high-quality development of multiple strategically emerging industries in China.
