ShinEtsu KBM-503  is 3-Methacryloxypropyl trimethoxysilane. Acts as a coupling agent. Its individual molecules contain methacryloxy functional group and methoxy group characterized by different reactivity. It bonds organic material to inorganic material. KBM-503 is typically used in the form of a dilute aqueous solution. It is very effective with polyethylene, polypropylene, polystyrene, acrylonitrile butadiene styrene (ABS), unsaturated polyester and peroxide cross-linked EPDM. Also effective with polycarbonate, sulfur cross-linked EPM, acrylic, diallyl phthalate, polycarbonate and urethane. When it is used for surface treating an inorganic material to promote adhesion between the inorganic material and an organic material, it acts by forming chemical bonds with resins, hydrogen bonding with resins and improving the wettability as well as miscibility of resins. 

• Silicone or silane-based chemistry – All models are built on silicone or silane structures, offering surface reactivity and stability.

• Surface modification – They improve adhesion between dissimilar materials, especially inorganic fillers and organic resins.

• Moisture resistance – Enhance water repellency and durability in cured systems like composites, sealants, and coatings.

• Thermal and chemical stability – Maintain performance under heat, humidity, and chemical exposure in industrial environments.

• Versatile industrial use – Widely applied in electronics, cables, adhesives, coatings, and composite materials.

• Construction

• Sealants

• Primers

• Glass treatment

• Ceramics