Silane End Cappers
Isocyanatopropylmethyldiethoxysilane | Manta S122
Manta S122 is (3-isocyanatopropyl)methyldiethoxysilane (CAS 33491-28-0), an isocyanate-functional dialkoxy silane used to end-cap polyols in the synthesis of low-modulus silane-modified polymers (SMP) and SPUR systems for high-movement joint sealants. It releases ethanol rather than methanol on hydrolysis, and its dialkoxy structure reduces crosslink density.
- Grade
- S122
- Chemical Name
- (3-Isocyanatopropyl)methyldiethoxysilane
- CAS No.
- 33491-28-0
- Synonyms
- (gamma-Isocyanatopropyl)methyldiethoxysilane
- Form
- Straw liquid
Overview
Manta S122 is an isocyanate-functional silane with a reactive isocyanate group and a methyldiethoxy silyl group. Its dialkoxy structure acts as a linear chain extender, reducing crosslink density to produce flexible, low-modulus elastomers.
On hydrolysis, S122 releases ethanol rather than methanol. Formulators who need to avoid methanol as a hydrolysis by-product can select this diethoxy grade, which combines that by-product profile with the elongation of a dialkoxy end-capper.
Manta S121 has the same dialkoxy, chain-extending structure with methoxy groups and releases methanol. Manta S320 is the triethoxy grade: it also releases ethanol but has three hydrolyzable groups. S122 has two, and its methyl group limits 3D crosslinking.
Key Features
- Releases ethanol rather than methanol on moisture curing
- Methyl group limits 3D crosslinking, giving low-modulus, high-movement sealants and coatings
- Isocyanate group bonds quickly with amines, hydroxyls and polyols
- Enhances wet and dry adhesion to inorganic substrates while retaining coating flexibility
Cross-Reference
Manta S122 can be considered as an alternative to Shin-Etsu KBE-9207.
Trademarks are the property of their respective owners; no affiliation is implied.
Specifications
| Property | Typical Value |
|---|---|
| Molecular Weight | 217.34 |
| Appearance | Straw liquid |
| Purity (by GC, %) | 96.0 min |
| Density (ρ20°C, g/cm³) | 0.94±0.1 |
| Refractive Index (n25/D) | Approx. 1.4200 |
| Boiling Point | 235.0°C |
| Flash Point | 96°C Closed Cup |
Typical values from the current Technical Data Sheet.
Applications
- Polymer end-capping: end-capping of polyols in the synthesis of silane-modified polymers (SMP / MS Polymer) and SPUR systems
- High-movement joint sealants: expansion joint sealants that must accommodate large thermal expansion and contraction without cohesive failure
- Adhesives and coatings: additive or modifier in polyurethane systems that require high flexibility
Related applications: Adhesives & Sealants · Paints & Coatings
Packaging & Storage
Supplied in 20 kg, 25 kg iron pail, 200 kg drum.
Safety and Storage
Keep in a cool and dry place and avoid storage in direct sunlight. Shelf life is min. 12 months. It is shipped as hazardous substance.
Documents
- Technical Data Sheet · PDF Download TDS
- SDS and COA · on request Request Documents
Frequently Asked Questions
How do I decide between Manta S122 and Manta S121?
Both are dialkoxy isocyanatosilanes that act as chain extenders for low-modulus polymers. S122 is the diethoxy version and releases ethanol rather than methanol on moisture curing. S121 is the dimethoxy version and releases methanol, so the choice depends on which hydrolysis by-product your system can accept. Flash points also differ: S122 is 96°C Closed Cup and S121 is Approx. 71°C closed cup.
What sealant types benefit most from Manta S122 end-capping?
Expansion joint sealants that must absorb large thermal expansion and contraction without cohesive failure. The methyl group limits 3D crosslinking, producing low-modulus, high-movement SMP, MS Polymer and SPUR sealants.
What are the storage and shipping requirements for Manta S122?
Keep in a cool and dry place and avoid storage in direct sunlight. Shelf life is min. 12 months. It is shipped as a hazardous substance. It is supplied in 20 kg, 25 kg iron pail, 200 kg drum.
Is there a minimum order quantity for Manta S122?
There is no fixed minimum order quantity; quantities are agreed case by case. Use Request a Sample to start an evaluation and include your expected volume and application.
Related Products
S122 is one step in the sealant and adhesive formulation chain. One inquiry can cover the other raw materials in your formulation, with samples, technical documents, quotation and shipment handled together.
Looking for a different purity, functional group, or a structure not listed here? Contact our technical team.
Talk to our technical team
Tell us your application, target properties and estimated quantity. We will suggest grades and arrange documents or samples.