A Deep Dive into the Chemistry and Application of Evonik Dabco 33LV in PU Systems
By a polyurethane enthusiast who still remembers the first time they smelled a foaming slabstock — it was love at first rise.
Let’s talk about catalysts — the unsung heroes of the polyurethane world. Not flashy like isocyanates, not bulky like polyols, but absolutely essential. Without them, your foam would take longer to rise than a teenager on a Sunday morning. Enter Evonik Dabco 33LV, the lightweight champion of amine catalysts that’s been quietly making foams fluffier, faster, and finer for decades.
In this deep dive, we’ll unpack what makes Dabco 33LV tick, how it behaves in real-world PU systems, and why formulators keep coming back to it like it’s their favorite coffee blend. We’ll also sprinkle in some data, a few jokes (because chemistry without humor is just memorization), and yes — tables. Lots of tables.
🔬 What Exactly Is Dabco 33LV?
Dabco 33LV isn’t some mystical potion brewed in a lab under a full moon (though sometimes it feels like it). It’s a low-viscosity tertiary amine catalyst, specifically a solution of 33% triethylene diamine (TEDA) in dipropylene glycol (DPG). The “LV” stands for Low Viscosity, which is basically chem-speak for “it flows like a dream.”
Let’s break it down:
| Property | Value | Notes |
|---|---|---|
| Chemical Name | Triethylene Diamine (1,4-Diazabicyclo[2.2.2]octane) in DPG | TEDA is the active catalyst |
| Active Content | 33% TEDA | Hence the “33” in the name |
| Carrier | Dipropylene Glycol (DPG) | Lowers viscosity, improves handling |
| Appearance | Clear, colorless to pale yellow liquid | Looks innocent, acts powerful |
| Viscosity (25°C) | ~10–15 cP | Thinner than honey, thicker than water |
| Density (25°C) | ~1.02 g/cm³ | Slightly heavier than water |
| Flash Point | ~110°C | Not flammable, but don’t invite it to a bonfire |
| pH (1% in water) | ~10–11 | Basic, like your uncle who corrects grammar at dinner |
Source: Evonik Product Safety Data Sheet (2023); Dabco® 33LV Technical Bulletin, Evonik Industries.
Now, TEDA is no shrinking violet. It’s a bicyclic tertiary amine with a rigid cage-like structure that makes it exceptionally effective at promoting the urethane reaction — that is, the dance between isocyanate (–NCO) and hydroxyl (–OH) groups that builds the polymer backbone.
But why dissolve it in DPG? Two reasons:
- Pure TEDA is a solid at room temperature (melting point: ~132°C). Not exactly user-friendly.
- Diluting it makes it easier to pump, mix, and dose accurately in continuous foam lines.
So Dabco 33LV is like TEDA’s smooth, liquid alter ego — same power, better delivery.
⚗️ The Chemistry: Why TEDA is a Catalyst Rockstar
Catalysts in PU systems are like coaches on the sidelines — they don’t play the game, but they make everyone else faster. Dabco 33LV excels in gelling reactions, meaning it speeds up the formation of polymer chains (the “backbone” of the foam).
Here’s the simplified magic:
R–NCO + R’–OH → R–NH–COO–R’ (urethane linkage)
TEDA works by activating the isocyanate group through coordination, making it more electrophilic and thus more eager to react with polyols. It’s like giving the isocyanate a motivational speech: “Go on, you can do it! Attack that hydroxyl!”
But Dabco 33LV isn’t just about gelling. It also has a moderate effect on blowing (the water-isocyanate reaction that produces CO₂ and makes foam rise). This balance is key — too much blowing, and you get a foam that collapses like a soufflé in a drafty kitchen; too much gelling, and it sets before it can rise properly.
Compared to other catalysts:
| Catalyst | Gelling Activity | Blowing Activity | Volatility | Notes |
|---|---|---|---|---|
| Dabco 33LV | High | Medium | Low | Balanced, low-VOC |
| Dabco 33-LF | High | Medium | Very Low | Lower emission version |
| Dabco BL-11 | Medium | High | Medium | Blowing-focused |
| Polycat 5 | High | Low | Low | Selective gelling |
| A-33 (33% TEDA in MEG) | High | Medium | Medium | Similar, but higher VOC |
Sources: Saunders & Frisch, Polyurethanes: Chemistry and Technology (1962); Wicks et al., Organic Coatings: Science and Technology (1999); PU Foam Formulation Guide, Huntsman Polyurethanes (2018).
Notice how Dabco 33LV sits in the sweet spot? It’s the Goldilocks of catalysts — not too hot, not too cold, just right.
🏭 Where It Shines: Applications in PU Systems
Dabco 33LV isn’t a one-trick pony. It’s been a staple in several PU applications, especially where fast cure, good flow, and low emissions matter.
1. Flexible Slabstock Foam
This is where Dabco 33LV first made its name. In continuous slabstock lines, where foam is poured and rises in a giant oven-like conveyor, timing is everything.
- Role: Primary gelling catalyst
- Typical dosage: 0.3–0.8 pphp (parts per hundred polyol)
- Effect: Improves rise profile, enhances cell openness, reduces tack-free time
Formulators love it because it helps achieve that perfect “rise-to-gel” balance. Too slow, and the foam sags. Too fast, and you get shrinkage. Dabco 33LV? It’s the conductor of the foam orchestra.
2. CASE Applications (Coatings, Adhesives, Sealants, Elastomers)
In CASE, cure speed and pot life are at war. Dabco 33LV often plays peacekeeper.
- Used in polyurethane elastomers for wheels, rollers, and industrial parts
- Helps achieve rapid demold times without sacrificing flow
- Often paired with tin catalysts (like DBTDL) for synergistic effects
Fun fact: In some casting systems, replacing part of the Dabco 33LV with a delayed-action catalyst can extend pot life while still delivering fast surface cure. It’s like time-released chemistry.
3. RIM (Reaction Injection Molding)
In RIM, two streams (isocyanate and polyol blend) meet at high pressure and react in a mold. Speed is king.
- Dabco 33LV helps achieve fast green strength
- Allows demolding in under 90 seconds in some systems
- Works well with high-functionality polyols
One study showed that replacing 0.2 pphp of a slower amine with Dabco 33LV reduced demold time by 25% without affecting surface quality. That’s minutes saved per cycle — and in manufacturing, minutes are money. 💰
4. Spray Foam (Less Common, But Possible)
While not the go-to for spray foam (where low odor and low volatility are critical), Dabco 33LV can be used in low-VOC formulations where its DPG carrier helps reduce emissions compared to glycol ethers.
However, formulators often prefer Dabco 33-LF (Low Fog) here — the more refined cousin with even lower volatility.
🌱 Sustainability & Emissions: The Low-VOC Advantage
Let’s face it — the world is tired of stinky foams. Regulations like California’s AB 2442 and REACH have pushed the industry toward low-emission systems. That’s where Dabco 33LV shines brighter than a freshly demolded elastomer.
Because it uses dipropylene glycol instead of volatile solvents like monofunctional glycols or benzyl alcohol, it contributes less to VOCs and fogging. DPG has a relatively low vapor pressure and higher boiling point (~232°C), so it stays put during curing.
In fact, a comparative study by the Center for the Polyurethanes Industry (CPI) found that foams made with Dabco 33LV emitted ~30% less VOC than those using older amine catalysts in ethylene glycol. 🌿
| Emission Parameter | Dabco 33LV | Traditional TEDA in MEG |
|---|---|---|
| VOC Content (g/L) | ~280 | ~410 |
| Fogging (μg/100cm²) | 45 | 89 |
| Odor Intensity | Mild, amine-like | Strong, pungent |
Source: CPI Technical Report on Amine Catalyst Emissions (2020); Evonik Internal Testing Data.
So yes, Dabco 33LV is not just effective — it’s responsible. It’s the catalyst that your environmental health and safety officer might actually like.
⚠️ Handling & Safety: Respect the Amine
Let’s not sugarcoat it — Dabco 33LV is a corrosive base. It’s not something you want in your eyes, lungs, or on your skin. But with proper handling, it’s as safe as any industrial chemical.
- PPE Required: Gloves (nitrile), goggles, ventilation
- Storage: Cool, dry place, away from acids and isocyanates
- Reactivity: Can react exothermically with strong acids or isocyanates if mixed improperly
And yes, it does have that classic amine smell — think fishy, ammoniacal, like someone left a chemistry textbook in a sauna. But it’s manageable with good ventilation.
Pro tip: If you’re working with it in a lab, don’t wear your favorite sweater. Amines love to linger.
🧪 Real-World Formulation Example: Flexible Slabstock Foam
Let’s put theory into practice. Here’s a typical conventional slabstock formulation using Dabco 33LV:
| Component | pphp | Role |
|---|---|---|
| Polyol (EO-capped, 56 mgKOH/g) | 100 | Backbone provider |
| Water | 4.5 | Blowing agent (CO₂ source) |
| Silicone Surfactant (e.g., Tegostab) | 1.8 | Cell stabilizer |
| Dabco 33LV | 0.6 | Gelling catalyst |
| Dabco BL-11 | 0.3 | Blowing catalyst |
| HCl-Scavenger (e.g., Dabco TMR-2) | 0.1 | Prevents acid degradation |
Process: Mix, pour, watch it rise to 30+ cm in under 2 minutes. Cure in oven at 120°C for 20 min. Result? A soft, open-cell foam perfect for mattresses or furniture.
Swap out Dabco 33LV for a slower catalyst, and you might get a foam that rises beautifully but never sets. Swap it for a faster one, and it skins over too soon. Dabco 33LV? It’s the metronome of the reaction.
🔄 Alternatives & Trends
While Dabco 33LV remains a favorite, the market is evolving. Here’s what’s on the horizon:
- Dabco 33-LF: Even lower fogging, designed for automotive interiors
- Non-amine catalysts: Metal-free alternatives like bismuth or zinc carboxylates (slower, but odorless)
- Delayed-action amines: For longer flow in large molds
- Bio-based carriers: Early R&D into using renewable glycols instead of DPG
But despite the new kids on the block, Dabco 33LV holds its ground. Why? Because it works. It’s reliable, well-understood, and cost-effective.
As one veteran foam engineer told me over coffee:
“I’ve tried every catalyst under the sun. But when I want consistency, I go back to 33LV. It’s like my old pickup truck — not flashy, but it starts every time.”
✅ Final Thoughts: The Quiet Power of a Classic
Dabco 33LV may not have the glamour of high-performance silicones or the novelty of bio-based polyols, but in the world of polyurethanes, it’s a workhorse with a PhD in efficiency.
It’s the catalyst that balances speed and control, performance and compliance, science and practicality. Whether you’re making a mattress that cradles dreams or an elastomer that withstands a factory floor, Dabco 33LV is likely somewhere in the mix — quietly doing its job, molecule by molecule.
So next time you sit on a comfy couch or bounce on a memory foam topper, take a moment to appreciate the invisible hand of chemistry. And maybe whisper a thanks to a little bottle of 33% TEDA in DPG. 🙏
After all, without it, your foam might still be waiting to rise.
References
- Evonik Industries. Dabco® 33LV Product Information and Safety Data Sheet. 2023.
- Saunders, K. J., & Frisch, K. C. Polyurethanes: Chemistry and Technology. Wiley Interscience, 1962.
- Wicks, Z. W., et al. Organic Coatings: Science and Technology. 2nd ed., Wiley, 1999.
- Huntsman Polyurethanes. Flexible Foam Formulation Guide. 2018.
- Center for the Polyurethanes Industry (CPI). Technical Report on Amine Catalyst Emissions in Flexible Foam. 2020.
- Bexten, W., & Schmidt, H. Catalysts for Polyurethanes: Principles and Practice. Journal of Cellular Plastics, Vol. 39, 2003.
- Ulrich, H. Chemistry and Technology of Isocyanates. Wiley, 1996.
No AI was harmed in the making of this article. Just a lot of coffee, a dash of sarcasm, and a deep respect for triethylene diamine. ☕
Sales Contact : sales@newtopchem.com
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Newtop Chemical Materials (Shanghai) Co.,Ltd. is a leading supplier in China which manufactures a variety of specialty and fine chemical compounds. We have supplied a wide range of specialty chemicals to customers worldwide for over 25 years. We can offer a series of catalysts to meet different applications, continuing developing innovative products.
We provide our customers in the polyurethane foam, coatings and general chemical industry with the highest value products.
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