From basic chemistry to global industrial innovation

Silicone sealant (also known as silicone adhesive) is a type of high-molecular elastomer based on polysiloxane, widely used in construction, automobiles, new energy, electronics and other fields. The core of its production principle lies in the cross-linking reaction of silicon-oxygen chains. Through chemical reactions, linear polysiloxane is transformed into a three-dimensional network structure, thereby achieving functions such as sealing, bonding, and weather resistance. The following is an analysis of the technology, market and innovation trends of the global silicone sealant industry. 

I. Production Principle of Silicone Adhesive: Chemical Foundation and Core Process
Basic Chemical Composition 

Main chain structure: Silicone adhesive is based on α,ω-dihydroxy polydimethylsiloxane (referred to as 107 adhesive), whose main chain is composed of silicon-oxygen bonds (Si-O), and the side groups are methyl or other organic groups. This structure endows the silicone adhesive with characteristics such as resistance to high and low temperatures (-60℃ to 250℃) and resistance to ultraviolet rays. 

Crosslinking reaction: The curing of silicone sealant relies on the reaction between the crosslinking agent and moisture in the air. For example:


Acidic adhesive: Using methyl triethoxy silane as the crosslinking agent, it releases acetic acid upon water dissolution, forming a Si-O-Si network. 

Neutral adhesive: It uses deketimox type (such as methyl tributylketimox-based silane) or deol type crosslinking agents. During the curing process, ketimox or alcohol substances are released, resulting in better environmental friendliness. 

Key additives: 

Fillers: Calcium carbonate, aerogel silica, etc. enhance mechanical properties; aluminum hydroxide and other inorganic flame retardants improve fire resistance. 

Catalyst: Organic tin (such as dibutyl dilauryl tin) or titanate, which accelerates curing. 

Coupling agent: Improves adhesion. For example, silane coupling agents enhance the bonding strength to glass and metals. 

Production process flow 

Mixed dehydration: The base material and filler are dehydrated and mixed in a vacuum kneader at a temperature range of 80°C to 150°C. The vacuum pressure is usually controlled at 0.06 to 0.1 MPa to prevent the formation of bubbles. 

Crosslinking and curing: After adding crosslinking agents and catalysts, a homogeneous paste is formed through a mixed reaction in a vacuum environment. For instance, the three-step vacuum mixing method can reduce the acetic acid release from acidic gels. 

Packaging and storage: For single-component glue, it is directly sealed; for two-component glue, the base material and curing agent are separately packaged, and they should be mixed proportionally when used. 

II. Technological Innovation: Environmental Protection and High Performance as Main Trends
Environmental upgrading 

Non-toxic formula: Utilizes non-halogen flame retardants (such as aluminum hydroxide) and bio-based raw materials (such as castor seed oil) to replace the traditional toxic silane coupling agents. 

Low VOC technology: Titanium oxide catalyst replaces organic tin, reducing VOC emissions by over 40%; Neutral deketox type adhesives have no irritating odor during curing. 

High-performance breakthrough 

Quick curing: Optimize the proportion of the curing agent (such as increasing the proportion of vinyl tributyloxime silane), and the drying time after application is reduced to 5 minutes. 

Functionalization modification: 

High-temperature resistance: The addition of phenyl siloxane (such as α,ω-dihydroxy polydiethylsiloxane) enhances the heat resistance to 300℃. 

Low modulus and high elasticity: The modulus is adjusted through chain extenders and toluene diisocyanate, and the elongation rate can reach over 600%, suitable for bridge expansion joints. 

Mold prevention and barrier: By adding nano-silica and mold inhibitors, the gas permeability coefficient is reduced, preventing mold growth in humid and hot environments. 

Exploration of Intelligence and Self-Repairing Capabilities 

The microcapsule technology is integrated into the repair agent. When cracks occur, the active substances are automatically released, thereby extending the lifespan (for example, the sealing adhesive for power batteries is targeted to last for 15 years). 

The two-component adhesive used for photovoltaic modules contains a desiccant to prevent the formation of bubbles at high temperatures, ensuring the bonding strength. 

III. Market Dynamics: New Energy and Construction Dominate Growth
Expansion of Application Areas 

Construction industry: Curtain wall sealing, concrete joint treatment (low modulus sealant resisting displacement by ±50%), accounting for 70% of global demand. 

New Energy: 

Photovoltaic: Two-component silicone sealant has strong resistance to yellowing and weathering, and is used for component sealing. 

Electric vehicles: The sealing glue for the power battery pack needs to be resistant to high temperatures and fireproof, and the demand is expected to increase by 25% annually. 

Electronics and Healthcare: Precise dispensing technology is used in vascular robot sealing, capable of withstanding 5 million dynamic pressure tests. 

Global market landscape 

Regional distribution: The Asia-Pacific region accounts for over 50% of the global market share (with China being the main contributor), while Europe and the United States focus on high-end products. 

Competitive landscape: International companies such as Henkel, Wacker, and Dow dominate the high-end market; Chinese brands (such as Siliconbao Technology) have rapidly risen in the fields of photovoltaics and construction. 

IV. Regulations and Policies and Sustainable Development
Environmental protection regulations have tightened. 

The EU Eco-design Regulation (2024/1781) requires a low-carbon approach throughout the entire life cycle and restricts the use of harmful substances such as PFAS. 

China's GB/T 35609-2025 has added the "low-carbon attribute" indicator, promoting the research and development of biobased sealants. 

Upgrade of technical standards 

International standards (such as ISO 11600, ETAG002) strictly stipulate the bond strength and durability. 

The Chinese standard GB 16776-2025 has raised the safety factor of structural adhesives from 2.5 times to 4 times, and has imposed a mandatory requirement for low VOC content. 

V. Future Outlook
Material Innovation: Bio-based silicone sealant (such as modified with polylactic acid) reduces carbon emissions by 60%, and its market share will reach 30% by 2025. 

Intelligent production: The AI-driven dispensing process achieves an accuracy of ±0.03mm, and 4D-printed adhesives in the future will be capable of monitoring stress changes. 

Circular Economy: Biodegradable Sealant and Digital Passport (in accordance with ESPR requirements) Enhance Supply Chain Transparency. 

Summary: The fundamental principle of silicone sealant production is the precise cross-linking of siloxanes. In the future, the industry will evolve along three main directions: environmental protection, high performance, and intelligence. From building facades to space capsule seals, silicone sealant is supporting the global industrial upgrade with its "elastic power".