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3-ISOCYANATOPROPYLTRIS (TRIMETHYLSILOXY) SILANE

July 30, 2026

Product Identification

English name: 3-ISOCYANATOPROPYLTRIS(TRIMETHYLSILOXY)SILANE
CAS No. : 25357-82-8
Molecular formula: C₁₃H₃₃NO₄Si₄
Molecular weight: 379.75
Structural Formula:
Appearance：Colourless to pale yellow to yellow liquid
Purity：98% Min

Product Overview

We are pleased to recommend our core functional silane monomer – 3-(3-isocyanatopropyl)-1,1,1,5,5,5-hexamethyl-3-[(trimethylsilyl)oxy]trisiloxane (abbreviated as isocyanatopropyltris(trimethylsiloxy)silane).

Leveraging a unique dual‑functional molecular structure – combining a highly reactive isocyanate group (–NCO) with a branched tris(trimethylsiloxy)silane hydrophobic skeleton – this product demonstrates significant application potential in organic synthesis, high‑performance coatings, composite materials, and surface modification. It is particularly suitable for R&D and industrial scenarios requiring low‑surface‑energy modification, targeted isocyanate grafting, and stain‑resistant/anti‑graffiti systems.

1. Core Highlights and Unique Molecular Value

Dual‑function synergy: The –NCO group readily undergoes efficient addition reactions with active hydrogens (e.g., –OH, –NH₂, –SH) under mild conditions, enabling covalent grafting. Meanwhile, the branched tris(trimethylsiloxy)silane backbone tends to migrate and enrich at material interfaces, imparting a long‑lasting extremely low surface energy to substrates.
Excellent compatibility: Compared with linear polydimethylsiloxanes, the branched trisiloxane structure significantly improves compatibility with various organic polymer systems such as polyurethanes, acrylics, epoxies, and polyamides, effectively suppressing exudation and macroscopic phase separation.
Long‑lasting functional stability: Once grafted into polymer networks, the siloxane segments retain their slip, weatherability, hydrophobicity, and low surface tension over time. The product also exhibits good storage stability at room temperature.

2. Main Application Areas

Based on its molecular characteristics, this product is suitable for the following R&D and production scenarios:

① Resin and polymer modification synthesis
Used in the synthesis of polyurethanes, polyureas, acrylic resins, and silicone‑hybrid polymers, introducing low‑surface‑energy siloxane segments into the main or side chains via –NCO linkages to prepare self‑lubricating, antifouling, and hydrophobic specialty resins.

② Coatings, inks, and UV/EB curing systems
Acts as a reactive slip agent and anti‑graffiti additive. Unlike non‑reactive silicone oils, this product can be chemically bonded into the film network, providing long‑term hydrophobicity, anti‑adhesion, and scratch resistance without migration or exudation. Suitable for wood coatings, plastic paints, and UV/EB‑curable coatings.

③ Surface treatment of powders and fillers
Used for the surface modification of inorganic powders containing hydroxyl groups, such as nano‑silica and metal oxides. The introduced flexible siloxane segments improve dispersibility in organic media, reduce system viscosity, and enhance the final product’s hydrophobicity and water resistance.

④ Composite interface modification
As an interfacial coupling agent, it can optimize the interface between glass/carbon fibers or inorganic fillers and organic resins, improving interfacial bonding strength while imparting water‑ and weather‑resistance to the composite surface.

⑤ Functional finishing for fabrics and films
Can be used to prepare reactive hydrophobic finishing agents for modifying films, nonwovens, and textiles, constructing durable hydrophobic and breathable interfaces.

⑥ Organic synthesis intermediate
Serves as a silicon‑containing isocyanate building block for constructing functional silicone derivatives, organic‑inorganic hybrid materials, and other fine chemicals.

3. Core Product Advantages

High purity assurance: Mature synthesis and distillation purification processes effectively control free monomers, hydrolysis by‑products, and residual isocyanate content, meeting the rigorous quality requirements of advanced new materials and precision coatings.
Excellent batch‑to‑batch consistency: A comprehensive quality control system ensures that each batch maintains high consistency in purity and other key indicators, guaranteeing reproducible performance in customer formulations.
Reliable supply capability: As one of our key silane product lines, we have established large‑scale production capacity to provide long‑term, stable, and sufficient supply, eliminating concerns about availability.
Professional technical support: Customized packaging and dispensing services are available. Our technical team offers full consultation and solutions on formulation selection, process adaptation, storage stability, and more.

4. Why Choose This Product?

When designing reactive silicone‑modified systems, balancing covalent bonding reactivity with effective surface enrichment of silicone segments is critical to performance.

3‑(3‑Isocyanatopropyl)‑1,1,1,5,5,5‑hexamethyl‑3‑[(trimethylsilyl)oxy]trisiloxane precisely achieves this balance – the highly reactive –NCO group ensures strong chemical grafting, while the branched tris(trimethylsiloxy)silane skeleton provides superior low‑surface‑energy properties, while avoiding the common drawbacks of conventional polydimethylsiloxane additives, such as easy exudation and poor compatibility.

Whether you are developing long‑lasting antifouling coatings, specialty modified polyurethanes, nanofiller surface modification systems, or exploring organic‑inorganic hybrid materials, the purity and stability of this product will provide solid support for your R&D and production scale‑up.