TDI Trimer

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Chemical Name: 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6-trione

Molecular Formula: C27H18N6O6

Molecular Weight: 522.4

CAS Numbers: 9019-85-6 and 26603-40-7

EINECS Number: 247-840-6.

The CAS number for general TDI homopolymer (1,3-diisocyanatomethyl-benzene homopolymer) is 9017-01-0; the CAS number for 2,4-TDI homopolymer is 26006-20-2. TDI trimer products belong to the TDI homopolymer category.

Structural Formula:

Physicochemical Properties

The common industrial product is a 50% solution of TDI trimer in butyl acetate, a colorless to light yellow liquid with medium to low viscosity, and an NCO group mass fraction of approximately 8%. Typical properties of TDI trimer products can be found in the product specifications of relevant manufacturers.

The theoretical NCO mass fraction of pure TDI trimer is 24%, but in practice, the NCO mass fraction of the solid content in TDI trimer products is around 16%. This is because the trimer product contains some oligomers, which reduces the actual NCO content.

Characteristics and Uses

TDI trimer has high reactivity and is generally used as a curing agent for fast-drying two-component polyurethane coatings. Application areas include furniture coatings, industrial in-line coatings, etc.; it can also be used as a curing agent component for room-temperature curing two-component polyurethane adhesives. It provides the paint film with outstanding fast-drying and filling properties, high hardness, and good heat resistance. The disadvantage is that it is not light-resistant and will yellow.