3-Methacryloxypropyltrimethoxysilane (A-174 / KH-570)

CAS 2530-85-0In StockSample available

Key Features

  • Methacrylate group reacts with UPR, VER, acrylic, and UV-curable resin systems
  • Broader resin compatibility than vinylsilanes due to higher methacrylate reactivity
  • Preferred silane for UV-curable fiber composites and mineral-filled UV coatings
  • Higher flash point (112°C) than vinylsilanes — safer handling
  • One of the most versatile silane coupling agents for mineral fillers in thermosets

3-Methacryloxypropyltrimethoxysilane (MPS, A-174/KH-570) is one of the most versatile and widely used silane coupling agents in the composites and coatings industry. It combines a methacrylate functional group that co-reacts with radical-curable resin systems (UPR, VER, acrylic, UV-curable) and three methoxy groups for rapid bonding to glass, mineral, and metal oxide surfaces.

The methacrylate functionality of A-174 is reactive with a broader range of resin systems than vinylsilanes, including unsaturated polyesters, vinyl esters, acrylic systems, and UV/EB-curable formulations. The bulkier methacrylate group provides better coupling efficiency in polar resin matrices than the vinyl group due to its higher reactivity and better spatial compatibility with the resin polymer chain network. This makes A-174 the preferred silane for glass fiber sizing in acrylic-UPR co-cure systems and for UV-curable composite applications.

For mineral filler treatment (ATH, silica, calcined kaolin), A-174 provides significantly improved mechanical performance in UPR, VER, and acrylic resin systems. Treatment at 0.5–2.0% on filler weight dramatically improves flexural strength, impact resistance, and water resistance of the filled composite. The methacrylate group is also reactive in UV-curing systems without modification, making it the coupling agent of choice for UV-curable fiber-reinforced composites and UV-curable mineral-filled coatings.

Specifications

ParameterValue
Purity≥ 97.0%
AppearanceColorless to pale yellow liquid
CAS Number2530-85-0
Flash point112°C
Boiling point255°C
Chemical name3-Methacryloxypropyltrimethoxysilane
Density (20°C)1.040–1.050 g/cm³
Molecular weight248.4 g/mol
Molecular formulaCH₂=C(CH₃)COO(CH₂)₃Si(OCH₃)₃
Contains inhibitor50–100 ppm MEHQ

Applications

Glass fiber sizing for UPR, VER, and acrylic composite systemsSurface treatment of ATH, silica, and kaolin in UPR/VER compositesUV-curable fiber-reinforced composite applicationsMineral-filled UV-curable coating and sealant systemsAdhesion promoter for glass and mineral substrates in acrylic adhesives

FAQ

Yes, A-174 contains 50–100 ppm MEHQ (monomethyl ether hydroquinone) as a stabilizer to prevent premature methacrylate polymerization during storage. This inhibitor is typically not removed before use, as the concentration is too low to affect cure performance in composite applications. For UV-curable systems, the inhibitor may slightly extend induction period — this is normally accounted for by the UV formulation. Do not heat A-174 above its boiling point without adequate inhibitor.

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