MSI (PTSI) p-toluenesulfonyl isocyanate CAS 4083-64-1

Short Description:

Chemical Name: p-toluenesulfonyl isocyanate

Synonyms: Tosylisocyanate, p-toluenesulfonyl isocyanate, para-tosylisocyanate, 4-methylbenzenesulfonyl isocyanate

Code: MSI (PTSI)

CAS No.: 4083-64-1

Product Detail

Product Tags

Product Description

MSI (PTSI), p-toluenesulfonyl isocyanate, a commonly used monoisocyanate, a highly reactive compound which is widely used as a dehydrating agent in chemical products, such as solvents, fillings, pigments and pitch tar areas.  Being a moisture scavenger for solvent-based polyurethane (PU) coatings, sealants, adhesives and as an intermediate of various industrially important chemicals. 

p-toluenesulfonyl isocyanate (PTSI) prevents undesirable premature reaction of the painting & coating, therefore, it allows formulators to produce high quality polyurethanes.  By using Harttive MSI in the production of polyurethane paints, the loss of gloss, yellowing and reactive foam caused by the wet surface in the system are all reduced.  p-toluenesulfonyl isocyanate can also be a stabilizer additive for moisture-curing materials to prevent deterioration or/and discoloration while storage.

Performance & Features

MSI (PTSI) reacts with water, giving off carbon dioxide and resulting in the formation of reaction products which are soluble in conventional paint formulations. Approximately 12g of the stabilizer is theoretically required for reacting with 1g of water. Experience has shown, however, that the reaction is more effective in the presence of a surplus of MSI(PTSI). Compatibility with paint binders should always be tested beforehand.

p-toluenesulfonyl isocyanate is recommended to be used as a chain terminator during polymerization and as a remover of unwanted reactive functional groups in PU raw materials. In coal tar PU coatings, MSI can be used to neutralize amines and OH functional groups and remove water in tar to avoid foaming and premature gelation when tar is mixed with PU prepolymer.


- Eliminates the effects of humidity and prevents moisture related problems in polyurethane coatings

- Low viscosity, monofunctional isocyanate which chemically reacts with water to form an inert amide

- Used for the dehydration of solvents, fillers, pigments and bituminous tars

- Improves the storage stability of diisocyanates against decomposition and discoloration

- Removes moisture introduced with solvents, pigments, and fillers in Single-component and Dual-component PU systems


MSI (PTSI) is used as a stabilizer for moisture-curing materials. It prevents undesirable premature reaction of the painting & coating. p-toluenesulfonyl isocyanat is commonly applied as following areas:

- Single-component and Dual-component polyurethane adhesives and sealants.

- Single-component and Dual-component polyurethane coatings and paints.

- Solvents

- Pigments

- Fillers

- Reagents



P-Toluenesulfonyl Isocyanate(PTSI)



Batch No

20240110 Packing 20kg/barrel Quantity 5000kgs
Date of manufacturing 2024-01-10




Assay, %



-NCO Content, %



Color, APHA



Content of PTSC, %

≤ 1.0


Packing & Storage

Packing: 20kgs, 180/iron drum.

Storage and transportation: Harttive MSI (PTSI) is moisture-sensitive and should therefore always be stored in tightly sealed original containers at temperatures between 5°C and 30 °C. Once opened, containers should be resealed immediately after each removal of the product. Keep away from alcohols, strong bases, amines, strong oxidizing agents.

Shelf life: 6 months since the date of production.

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