Siwin-M330A is an alkoxysilane-terminated polyether polymer, commonly classified as a modified silane (MS) polymer or silyl-terminated polyether (STP). Its molecular structure features a polyoxypropylene main chain terminated with alkoxysilane groups at both ends. In the presence of atmospheric moisture and a suitable catalyst, the terminal alkoxy groups hydrolyze and condense to form siloxane crosslinks, curing the liquid polymer into a flexible elastomer. This moisture-curing mechanism makes M330A a base resin for formulating elastic sealants, structural adhesives, and sealing coatings used across multiple industrial sectors.
The polyoxypropylene backbone provides the polymer with low glass transition temperature, contributing to consistent flexibility across a broad temperature range. The terminal alkoxysilane groups are the reactive sites responsible for moisture-triggered crosslinking. Unlike polyurethane polymers that rely on isocyanate chemistry, MS polymers cure through silanol condensation, producing alcohol as a byproduct rather than releasing free isocyanates. This distinction supports formulation of low-VOC, isocyanate-free sealants and adhesives for commercial applications where worker safety and environmental compliance are specified.
Parameter | Specification |
Product No. | Siwin-M330A |
Chemical Name | Silane modified polyether / MS Polymer |
CAS No. | 216597-12-5 |
Appearance | Colorless, transparent, viscous liquid |
Flash point | > 100°C |
Viscosity (25°C) / mPa·s | 22000 - 32000 |
Density (25°C) / g/cm³ | 1.002 - 1.005 |
Activity | High activity |
Modulus | Medium-high modulus |
M330A cures at ambient temperature upon exposure to moisture, with cure rate adjustable through catalyst selection and loading. Formulations based on M330A develop adhesion to a wide range of substrates including glass, aluminum, steel, PVC, and wood, often without requiring primer treatment. The medium-high modulus character of M330A provides a balance of structural strength and elastic recovery, making it suitable for both sealing and bonding applications in construction and industrial assembly.
M330A-based formulations contain no solvent, no free isocyanate, and emit low levels of volatile organic compounds during cure. The cured sealant accepts paint and coatings applied to its surface, a property that differentiates MS polymer sealants from traditional silicone sealants which typically do not hold paint. These attributes support the use of M330A in projects subject to environmental regulations governing indoor air quality and construction site emissions.
M330A serves as the base resin for producing weatherproofing sealants, structural glazing adhesives, and joint sealants used in commercial building construction. Its ability to accommodate substrate movement while maintaining adhesion, combined with paintability and UV stability, supports its use in facade sealing, window installation, and interior construction applications where both performance and aesthetic finish are required.
In the transportation sector, M330A is formulated into elastic sealants for vehicle body assembly, rail car manufacturing, and container construction. The polymer's vibration-damping properties and resistance to thermal cycling contribute to durable seals in applications subject to mechanical stress and temperature variation.
The transparent nature of cured M330A supports its use in electronic potting compounds and encapsulation adhesives where optical clarity is desired. In new energy applications, formulations based on M330A are used for sealing and bonding in solar panel framing, battery module assembly, and other renewable energy components where moisture resistance and elastic compliance are specified.
M330A may be compounded with a range of fillers including nano calcium carbonate, ground calcium carbonate, fumed silica, silica powder, diatomaceous earth, and aluminum hydroxide. Fillers should be dehydrated prior to incorporation to prevent premature curing. Common additives include tackifiers, antioxidants, UV stabilizers, and mildew inhibitors. Plasticizers such as phthalates and low-molecular-weight polyethers may be used to adjust viscosity and modulus.
M330A supports both one-component and two-component formulation strategies. One-component systems cure by absorbing atmospheric moisture and offer convenience in field application, while two-component systems provide faster cure speed and deeper through-cure for thicker sections. Formulators select the system type based on production logistics, application method, and cure speed requirements of the target market.
M330A is available in IBC plastic drums (1000 kgs) and steel drums lined with aluminum foil bags (200 kgs). Custom packaging arrangements can be coordinated for volume orders. The product should be stored in a cool, dry place away from direct sunlight with containers tightly sealed to prevent moisture ingress. The shelf life is 12 months from the date of manufacture when stored under recommended conditions. The material is classified as a general non-hazardous chemical for transportation purposes.
M330A cures through moisture-triggered hydrolysis and condensation of its terminal alkoxysilane groups. In the presence of atmospheric moisture and a catalyst such as an organotin compound or amine, the alkoxy groups hydrolyze to form silanols, which then condense to create siloxane crosslinks, transforming the liquid polymer into a flexible elastomer.
MS polymers contain no free isocyanate and no solvent, produce low VOC emissions during cure, and accept surface paint applications. Silicone sealants generally do not hold paint, while polyurethane sealants contain isocyanates and may have higher VOC levels. MS polymers combine properties of both, offering elasticity and paintability.
Formulations based on M330A develop adhesion to a broad range of substrates including glass, aluminum, steel, stainless steel, PVC, wood, concrete, and various plastics, often without requiring a primer. Specific adhesion performance should be verified for each substrate and formulation combination.
M330A has a shelf life of 12 months when stored in unopened containers under cool, dry conditions away from direct sunlight. Containers must be kept tightly sealed to prevent moisture exposure, which would initiate premature curing of the polymer.
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