Name: Trimethylolpropane Triacrylate (TMPTA)
Brand: Coatingsink
SKU: tmpta-reactive-diluent
Availability: InStock

Question 1

Why does TMPTA cause high cure shrinkage and how can it be managed?

Accepted Answer

TMPTA has a high acrylate group density relative to its molecular weight, which means the volume contraction during polymerization is proportionally large. This causes significant cure shrinkage that can lead to stress cracking or poor adhesion on rigid substrates. Shrinkage is managed by blending TMPTA with high-molecular-weight oligomers (urethane acrylates, polyester acrylates) that dilute the acrylate density, or by limiting TMPTA to 10–25% of the total formulation.

Question 2

What is the difference between TMPTA and TPGDA as reactive diluents for UV inks?

Accepted Answer

TMPTA is trifunctional and produces a highly crosslinked, hard (Tg >100°C), chemically resistant cured film, but with higher viscosity (~100 mPa·s) and higher cure shrinkage. TPGDA (tripropylene glycol diacrylate) is difunctional, lower viscosity (~15 mPa·s), gives more flexible cured films, and has lower shrinkage. TMPTA is preferred when maximum hardness and crosslink density are needed; TPGDA is used when flexibility and low viscosity are priorities.

Purity	≥90%
Functionality	3 (trifunctional)
Tg (homopolymer)	>100°C
Viscosity (25°C)	100–120 mPa·s
Shrinkage (cure, estimated)	high — use with softer oligomers

Trimethylolpropane Triacrylate (TMPTA)

Specifications

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