Amine Catalyst A33 (33% triethylenediamine in dipropylene glycol) is the industry-standard tertiary amine catalyst for polyurethane foam. Ambizent supplies A33 to flexible, rigid and CASE manufacturers worldwide, with a Certificate of Analysis on every shipment.
Amine Catalyst A33 is one of the most widely used catalysts in the polyurethane industry — the tertiary amine workhorse that drives the gel and blow reactions in flexible, rigid and CASE systems alike. Ambizent supplies A33 to foam and polyurethane manufacturers worldwide, with the consistency and documentation a production line depends on.
What is Amine Catalyst A33?
Amine Catalyst A33 (A-33) is a solution of 33% triethylenediamine (TEDA, CAS 280-57-9) in 67% dipropylene glycol (DPG). Pure TEDA is a waxy solid at room temperature and difficult to dose accurately, so the industry standardised on this 33% liquid dilution — stable, easy to meter, and simple to blend into a polyol premix, while retaining strong catalytic activity. A33 is a clear to pale-yellow liquid, fully miscible with polyols and compatible with tin catalysts such as Stannous Octoate.
How A33 works
Triethylenediamine is a strongly active tertiary amine that catalyses two reactions simultaneously: the gel reaction (isocyanate with polyol, building the polymer network) and the blow reaction (isocyanate with water, generating CO&sub2; to expand the foam). Because A33 accelerates both reactions rather than favouring one, formulators typically balance it against a more gel-selective tin catalyst — commonly Stannous Octoate (T9) in flexible foam — to control cell structure, rise profile and cure speed precisely.
Amine Catalyst A33 (also written A-33) is a solution of 33% triethylenediamine (TEDA, CAS 280-57-9) in 67% dipropylene glycol (DPG). It is a strongly active tertiary amine catalyst used across the polyurethane industry to promote both the gelling (isocyanate-polyol) and blowing (isocyanate-water) reactions.
What is A33 used for?
A33 is used in flexible slabstock and moulded foam, rigid foam, high-resilience (HR) foam, and CASE applications (coatings, adhesives, sealants, elastomers). Because it accelerates both the gel and blow reactions, it is typically balanced with other amine or tin catalysts to control cell structure and rise profile.
How is A33 different from pure TEDA?
Pure triethylenediamine (100% TEDA) is a waxy solid at room temperature, which makes it awkward to dose accurately in liquid foam systems. Diluting it to 33% in dipropylene glycol gives a stable, easy-to-handle liquid that is simple to meter, while still delivering strong, balanced catalytic activity — which is why A33 (rather than solid TEDA) is the form most foam producers actually buy and use.
What dosage of A33 is typical?
Dosage varies by system and target rise/cure profile, typically a fraction of a part per hundred parts polyol (php) up to a few php, and is usually balanced against a tin catalyst (such as Stannous Octoate T9 in flexible foam) to control the gel/blow balance. Confirm the correct level for your formulation with lab trials.
How should A33 be stored?
Store in a sealed container in a cool, dry, well-ventilated area away from direct sunlight, moisture and incompatible materials. Amine catalysts can absorb atmospheric moisture and carbon dioxide over time, which affects reactivity, so containers should be kept tightly closed between uses.
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