On the glass curtain wall of Ping An Financial Center in Shenzhen, in the rocket fuel pipeline of Wenchang Aerospace Launch Site in Hainan, and in the anti-corrosion coating of the combustible ice mining platform in the South China Sea, a seemingly ordinary colloid - silicone sealant - is silently guarding the safety and efficiency of modern industry. As the core product of downstream applications of organosilicon, the technological evolution history of sealant reflects the leap of China's manufacturing industry from "following" to "running in parallel".


1、 Technological iteration: from "single function" to "full scene adaptation"
In the early days, silicone sealant was mainly used for elastic bonding of building curtain walls. With the expansion of application scenarios, there are three major directions for upgrading technology requirements:
Resistant to extreme environments: A deep-sea grade sealant developed by a certain enterprise can maintain sealing performance under conditions of -18 ℃ to 60 ℃ and a water pressure of 100MPa, and is used for sealing the observation window of the "Striver" manned submersible; A certain type of aviation sealant, by adding nano silica, expands its temperature resistance range to -55 ℃ to 200 ℃, meeting the sealing requirements of the J-20 fighter wing.
Rapid curing: LUMISIL launched by Wacker Chemie ® The 1K UV series single component UV curing adhesive reduces the curing time from the traditional 24 hours to 30 seconds, and is widely used in consumer electronics fields such as car displays and smart watches. The condensation UV dual curing technology developed by a certain enterprise has reduced the lamination time of photovoltaic module encapsulation adhesive from 15 minutes to 5 minutes, and increased production efficiency by three times.
Intelligent response: A shape memory silicone sealant developed by a certain university can automatically fill micro cracks of 0.1mm under temperature stimulation. It is applied to the sealing of nuclear power plant pipelines, reducing the risk of leakage by 90%.
2、 Vertical cultivation of application scenarios
The technological breakthrough of sealant promotes its application from traditional architecture to high-end manufacturing:
New energy vehicles: a low-density organic silicon sealant developed by a certain enterprise, with a density reduced from 1.2g/cm ³ to 0.8g/cm ³, helping to reduce the weight of battery packs by 15%; A certain model of wire harness sealant achieves electromagnetic shielding function by adding conductive particles, solving the electromagnetic interference problem of high-voltage wire harnesses.
Semiconductor packaging: A chip level bottom filling adhesive developed by a certain enterprise, with a viscosity reduced from 10000mPa · s to 500mPa · s, can penetrate to a chip gap of 50 μ m, improving packaging reliability; A certain type of temporary bonding adhesive can be quickly peeled off at 120 ℃, meeting the needs of temporary fixation of crystal circles in 3D packaging.
Medical Implant: A biodegradable silicone sealant developed by a certain enterprise can completely decompose into silicates and carbon dioxide in the body after 6 months. It is used for temporary fixation of cardiac occluders and nerve stimulation electrodes to avoid secondary surgical removal.
3、 Industry pain points and the path to breaking through
Although China has the world's largest production of silicone sealants, the high-end market is still monopolized by foreign companies. The core bottleneck lies in:
Raw material dependence: 70% of the raw materials required for high-end sealants, such as vinyl silicone oil and hydrogen containing silicone oil, rely on imports, resulting in high costs. A certain enterprise has increased its self-sufficiency rate of industrial silicon to 90% and reduced raw material costs by 25% through the construction of an integrated coal electricity silicon base.
Lack of standards: The national standard for MS adhesive used in prefabricated buildings has not yet been introduced, and there is a phenomenon of inferior products being sold as good in the market. A certain enterprise has collaborated with an industry association to develop enterprise standards, which include indicators such as siloxane content and tensile strength in the mandatory testing scope, promoting the standardized development of the industry.
Technical barrier: The purity requirement for semiconductor packaging adhesive is 9N (99.99999999%), which only a few domestic enterprises can meet. A certain enterprise has broken through the technological blockade by introducing equipment such as German gas chromatographs and American plasma mass spectrometers to control the metal impurity content below 0.1 ppb.
The technological evolution history of silicone sealant, from building curtain walls to deep-sea exploration, is a microcosm of China's manufacturing industry's transition from "large but not strong" to "strong but refined". In the future, with the rise of emerging industries such as 5G, artificial intelligence, and biomedicine, this' invisible guardian 'will surely usher in a broader stage.