Chemical structure of Silane-terminated polyether (Manta MS305D)

High-Hardness MS Polymer (Shore A 70) | Manta MS305D

Manta MS305D is a silane-terminated polyether (STPE) with high activity, high modulus and high hardness, used as a base polymer for moisture-curing elastic sealants, structural adhesives and protective coatings in industrial assembly, transportation and construction. It is solvent-free, contains no free isocyanates and is suitable for low-VOC formulations.

Grade: MS305D
Chemical Name: Silane-terminated polyether
Form: Transparent viscous liquid

Overview

Manta MS305D is a silane-terminated polyether (STPE, also known as silane-modified polymer, SMP) with a polyoxypropylene backbone. In moisture-curing systems it hydrolyzes and crosslinks with ambient humidity to form a durable network with high hardness, and it can be formulated as a one-component (1K) or two-component (2K) product with good bond strength on many substrates.

Compared with conventional silicone and polyurethane (PU) technologies, MS305D is solvent-free, suitable for low-VOC formulations and contains no free isocyanates, which avoids the isocyanate-related handling precautions of PU systems.

MS305D has a viscosity of 1,400 – 1,600 mPa·s at 25 °C, below the 4,000 – 5,000 mPa·s at 25 °C of Manta MS311. Both have high activity; MS305D has a high modulus where MS311 has a medium-high modulus.

Key Features

High activity, high modulus and high hardness
Good resistance to aging and yellowing
Good bond strength and tensile strength
Good resistance to water and chemical solvents
Good storage stability
Solvent-free and low odor
Can be blended with other polymers

Specifications

Typical properties of Manta MS305D
Property	Typical Value
Appearance	Transparent viscous liquid
Flash Point	≥ 100 °C
Viscosity (25 °C)	1,400 – 1,600 mPa·s
Density (25 °C)	1.002 – 1.005 g/cm³
Tack-Free Time	30 min
Tensile Strength	≥ 3.0 MPa
Elongation at Break	≥ 60 %
Hardness (Shore A)	70
pH Value	6 – 8
Activity	High
Modulus	High

Typical values from the current Technical Data Sheet.

Applications

Industrial adhesives and sealants: high-strength bonding and industrial joint sealing where high mechanical resistance is required
Coatings and potting: durable protective coatings; can be evaluated for electronic potting, with electrical properties to be verified in the final formulation
Transportation: structural assembly in rail vehicles and specialty vehicles where high hardness is required; can be evaluated for EV battery assembly
Construction: high-hardness bonding and sealing for window perimeters and facade cladding, with a paintable and non-staining finish
New energy: can be evaluated for sealing and fixing of solar panels and wind-energy components

Processing

Moisture: because the alkoxysilane groups are moisture-sensitive, keep storage and production conditions dry to prevent premature crosslinking.
Fillers: MS305D is compatible with PCC (nano precipitated calcium carbonate), GCC (ground calcium carbonate), fumed silica, silica flour, diatomaceous earth and aluminum hydroxide; the dosage can be adjusted to the requirements.
Drying: dry all fillers thoroughly to prevent premature gelation. Vinyltrimethoxysilane (VTMO) is recommended as a moisture scavenger.
Plasticizers: suitable plasticizers include phthalates (e.g., DINP, DIDP), PPG and other low-molecular-weight polyethers.
Additives: adhesion promoters, antioxidants, fungicides and UV/light stabilizers can be added to adjust the end-use properties.

Related applications: Adhesives & Sealants

Packaging & Storage

50 kg plastic drum with aluminum-foil liner bag;

200 kg drum with aluminum-foil liner bag;

1,000 kg IBC (tote);

Other pack sizes available on request.

Safety and Storage

Store in the tightly closed original container in a cool, dry place, protected from moisture and direct sunlight. Shelf life: 12 months from the date of production when stored as recommended. The product is classified as non-hazardous. Refer to the current Safety Data Sheet (SDS) for safety, handling and transport information.

Note: The values in this data sheet are typical values and are not intended for use in preparing specifications. Users should test the product to determine its suitability for their specific application.

Documents

Technical Data Sheet · PDF Download TDS
SDS and COA · on request Request Documents

Frequently Asked Questions

What cured mechanical properties does Manta MS305D deliver?

MS305D has a tack-free time of 30 min, tensile strength of ≥ 3.0 MPa, elongation at break of ≥ 60 % and Shore A hardness of 70. This high-activity, high-modulus profile is aimed at bonding where high mechanical resistance is required.

Which fillers can be compounded into MS305D systems?

MS305D is compatible with PCC (nano precipitated calcium carbonate), GCC (ground calcium carbonate), fumed silica, silica flour, diatomaceous earth and aluminum hydroxide. Dry all fillers thoroughly to prevent premature gelation; vinyltrimethoxysilane (Manta V31) is recommended as a moisture scavenger.

When should MS305D be chosen over low-modulus Manta grades?

Choose MS305D when the application needs high hardness and high modulus, such as high-strength bonding or industrial joint sealing where high mechanical resistance is required. Low-modulus grades such as Manta MS27 and Manta MS201S are aimed at flexible, stress-relaxing joints such as expansion joints and facades.

Is MS305D suitable for new energy applications?

MS305D can be evaluated for EV battery assembly and for the sealing and fixing of solar panels and wind-energy components. Suitability depends on the final formulation and should be confirmed by application testing.

Need a finished adhesive or sealant rather than the polymer? See our custom MS adhesives and sealants service.

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