TDI-TMP Adduct

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The TDI-TMP adduct is an addition product of toluene diisocyanate and trimethylolpropane.

Molecular formula: C₃₃H₃₂O₉

Molecular weight: 656.6

CAS number:9017-09-8.

Additionally, the adduct of TDI, TMP, and DEG has a CAS number of 53317-61-6.

Structural Formula:

Physical and Chemical Properties

Pure TDI-TMP adduct is a solid. For ease of handling, a solvent is usually added during preparation, and it can be diluted with solvents such as ethyl acetate, butyl acetate, and acetone.

Appearance: Light yellow liquid, color (APHA) ≤ 80, Coronate L viscosity 1070–1760 mPa·s, free TDI content ≤ 0.12%.

Characteristics and Uses

The TDI-TMP adduct is the most commonly used aromatic polyisocyanate curing agent domestically and internationally. It is widely used in various two-component polyurethane coatings (such as furniture paints, floor varnishes, metal paints, plastic coatings, etc.), adhesives (general-purpose polyurethane adhesives, food packaging and beverage flexible plastic composite adhesives, paper-plastic composites), etc. The TDI-TMP adduct can also react with low-hydroxyl value polyester diols to prepare one-component moisture-curing polyurethane coatings.

The resulting coatings have high hardness, wear resistance, chemical resistance, and water resistance. Besides being used with polyester polyols and acrylate polyols to formulate polyurethane coatings, it can also react with hydroxyl-containing epoxy resins, alkyd resins, cellulose resins, castor oil, and vinyl resins. Because this type of crosslinking agent uses aromatic polyisocyanates, its disadvantage is poor light resistance; clear varnishes will yellow under prolonged outdoor sunlight exposure, and the gloss of colored paints will gradually disappear, or even chalk. TDI-TMP adducts are easy to prepare and more economical than other polyisocyanate curing agents. Many domestic adhesive and coating manufacturers produce them in-house. This product is used with hydroxyl-containing main components to form two-component polyurethane coatings and adhesives. Currently, products with a free TDI content of less than 0.7% can be manufactured domestically.