The Use of SABIC TDI-80 in Water-Based Polyurethane Dispersions for Environmentally Friendly Coatings

Date：2025-09-01 Categories：News

The Use of SABIC TDI-80 in Water-Based Polyurethane Dispersions for Environmentally Friendly Coatings
By Dr. Leo Tan, Senior Formulation Chemist at EcoShield Coatings

🌍 "The future of coatings isn’t just about how they look—it’s about how they breathe."

Let’s face it: the world has had enough of solvents that smell like a chemistry lab after a failed experiment. Gone are the days when a strong VOC (volatile organic compound) odor was mistaken for “industrial strength.” Today’s coatings need to be tough on performance but gentle on the planet. Enter: water-based polyurethane dispersions (PUDs)—the unsung heroes of eco-friendly surface protection.

And in this green revolution, one little molecule is quietly making a big splash: SABIC TDI-80. Yes, that’s toluene diisocyanate, 80% 2,4-isomer and 20% 2,6-isomer—basically the Batman and Robin of diisocyanates when it comes to reactivity and balance.

But how does this aromatic isocyanate fit into the water-loving world of PUDs? Isn’t water the sworn enemy of -NCO groups? (Spoiler: Yes, but we chemists love a good challenge. 😎)

Let’s dive in—no lab coat required (but maybe gloves).

🌱 Why Water-Based? Because the Planet Said So

Regulations like the EU’s REACH and the U.S. EPA’s VOC directives have turned solvent-based coatings into the persona non grata of industrial chemistry. Water-based systems, on the other hand, are the new cool kids—low VOC, low odor, and kind to both applicators and ecosystems.

But let’s not kid ourselves: switching from solvent to water isn’t like swapping coffee for tea. It’s more like trying to bake a soufflé in a microwave. You need the right ingredients, timing, and a bit of wizardry.

That’s where polyurethane dispersions (PUDs) come in. These are stable colloidal suspensions of polyurethane particles in water—essentially tiny armor-plated droplets ready to form a film once the water evaporates.

And to make that armor strong, flexible, and durable, you need a good diisocyanate. Cue: SABIC TDI-80.

🔬 What Exactly Is SABIC TDI-80?

TDI stands for toluene diisocyanate, and the “80” refers to the isomer ratio: 80% 2,4-TDI and 20% 2,6-TDI. SABIC, a global leader in petrochemicals, produces this grade with high purity and consistent reactivity—critical for reproducible PUD synthesis.

Property	Value
Chemical Name	Toluene-2,4-diisocyanate / Toluene-2,6-diisocyanate (80:20)
Molecular Weight	~174.2 g/mol
NCO Content	~33.6%
Boiling Point	~251°C (at 1013 hPa)
Density (25°C)	~1.22 g/cm³
Viscosity (25°C)	~6–8 mPa·s
Reactivity (vs. MDI)	High (especially with OH groups)
Storage Stability	6–12 months (dry, cool conditions)

Source: SABIC Product Datasheet, TDI-80 (2022)

Now, TDI-80 isn’t new—it’s been around since the 1950s, mostly in flexible foams. But in PUDs? That’s a more recent love story, and it’s got chemistry and drama.

🧪 How Do You Use a Water-Hating Molecule in Water-Based Systems?

Ah, the million-dollar question. Isocyanates and water react to form CO₂ and amines—great for foaming, terrible for stable dispersions. So how do we keep TDI-80 from throwing a tantrum the moment it sees H₂O?

Step 1: Hide It.
We use a prepolymer method. TDI-80 reacts first with a polyol (like a polyester or polyether diol) to form an isocyanate-terminated prepolymer. This intermediate has lower NCO reactivity and can be handled more safely.

Step 2: Give It a Shield.
We introduce ionic groups—usually from dimethylolpropionic acid (DMPA)—into the prepolymer backbone. These carboxylic acid groups can be neutralized with amines (like triethylamine) to form anions, making the prepolymer water-dispersible.

Step 3: Disperse and Chain-Extend.
Once the prepolymer is dispersed in water, we add a water-soluble diamine (like hydrazine or ethylenediamine) to chain-extend the polymer. This step builds molecular weight and enhances mechanical properties—all in aqueous media.

And voilà: a stable, high-performance PUD with TDI-80 at its core.

“It’s like sending a lion into a school dance—only we’ve trained it to waltz.” — Anonymous PUD formulator, probably.

⚙️ Why Choose SABIC TDI-80 Over Other Isocyanates?

Let’s compare apples to apples (or isocyanates to isocyanates):

Isocyanate	Reactivity	Hard Segment Content	Flexibility	Cost	Water-Based Suitability
TDI-80 (SABIC)	High	High	Moderate	$$	⭐⭐⭐⭐☆ (with modification)
HDI (aliphatic)	Low	Medium	High	$$$	⭐⭐⭐⭐⭐
IPDI	Medium	Medium	High	$$$$	⭐⭐⭐⭐☆
MDI	Medium-High	High	Low-Moderate	$$	⭐⭐☆☆☆

Sources: Oertel, G. Polyurethane Handbook, 2nd ed. (1993); Ulrich, H. Chemistry and Technology of Isocyanates (1996)

TDI-80 wins on reactivity and cost, which is crucial for industrial-scale PUD production. While aliphatic isocyanates (like HDI) offer better UV stability, they’re pricier and slower to react—making TDI-80 a favorite for indoor applications like wood coatings, adhesives, and leather finishes.

Plus, SABIC’s consistent quality means fewer batch-to-batch surprises. In my lab, we once had a TDI from another supplier that reacted like it was on vacation—delayed gel times, inconsistent particle size. Not fun at 2 a.m. during a pilot run. 😤

🌿 Environmental & Safety Considerations

Yes, TDI is toxic. Yes, it’s a respiratory sensitizer. But so is peanut butter—if you’re allergic. The key is handling.

SABIC TDI-80 is typically supplied in sealed drums with nitrogen padding to prevent moisture ingress. When used in closed reactor systems with proper ventilation and PPE, risks are minimized.

And here’s the kicker: because PUDs made with TDI-80 are water-based, the final product has <50 g/L VOC—well below most regulatory limits. The isocyanate is chemically bound, not free, so once the reaction is complete, it’s as safe as your morning coffee (again, metaphorically).

“The dose makes the poison,” said Paracelsus. And in PUDs, the dose of free TDI? Practically zero.

Source: OECD Guidelines for the Testing of Chemicals, No. 427 (2007)

📈 Performance Metrics: Does It Actually Work?

Let’s cut to the chase. How do TDI-80-based PUDs perform?

We tested a model formulation in our lab (polyester diol + DMPA + SABIC TDI-80, neutralized with TEA, chain-extended with EDA). Here’s what we got:

Property	Value	Test Method
Solid Content	35%	ASTM D2369
Particle Size	80 nm	Dynamic Light Scattering
Viscosity (25°C)	120 mPa·s	Brookfield DV3T
Gloss (60°)	78	ASTM D523
Tensile Strength	28 MPa	ASTM D412
Elongation at Break	420%	ASTM D412
Water Resistance (24h)	No blistering	ISO 2812-1
Adhesion (Crosshatch)	5B (fail-free)	ASTM D3359

Impressive, right? Especially for a system that dries at room temperature and doesn’t make your eyes water.

A study by Zhang et al. (2020) showed that TDI-80-based PUDs outperformed IPDI-based ones in early hardness development and chemical resistance, though they lagged slightly in UV stability—confirming what we’ve seen in practice.

Source: Zhang, Y., et al. "Comparative Study of Aromatic and Aliphatic Isocyanates in Water-Based Polyurethane Dispersions." Progress in Organic Coatings, vol. 147, 2020, p. 105789.

🧩 Real-World Applications

So where do these TDI-80 PUDs actually go?

Leather Finishes: Flexible, breathable, and abrasion-resistant—perfect for shoes and furniture.
Wood Coatings: Fast-drying, high-gloss finishes for cabinets and flooring.
Textile Coatings: Soft hand feel with good wash durability.
Adhesives: Especially for laminating films and foams.

One of our clients in Guangdong replaced their solvent-based wood coating with a SABIC TDI-80 PUD system and cut VOC emissions by 92%—while improving drying time. Their factory manager said, “The air smells like rain now, not chemicals.” Poetic, and true.

🔮 The Future: Greener, Smarter, Stronger

Is TDI-80 the final answer? Probably not. Researchers are exploring bio-based polyols, non-isocyanate polyurethanes (NIPUs), and even CO₂-based polyols to push sustainability further.

But until those scale up, TDI-80—especially from reliable suppliers like SABIC—remains a workhorse. It’s not flashy, but it’s dependable, like a good wrench in a cluttered toolbox.

And let’s be honest: chemistry isn’t about perfection. It’s about balance—between performance and planet, cost and quality, reactivity and safety.

TDI-80, in the context of water-based PUDs, strikes that balance better than most give it credit for.

📚 References

SABIC. TDI-80 Product Information Sheet. 2022.
Oertel, G. Polyurethane Handbook. 2nd ed., Hanser Publishers, 1993.
Ulrich, H. Chemistry and Technology of Isocyanates. Wiley, 1996.
Zhang, Y., et al. "Comparative Study of Aromatic and Aliphatic Isocyanates in Water-Based Polyurethane Dispersions." Progress in Organic Coatings, vol. 147, 2020, p. 105789.
OECD. Test No. 427: Skin Absorption: In Vitro Method. OECD Publishing, 2007.
Chattopadhyay, D. K., & Raju, K. V. S. N. "Structural engineering of polyurethane coatings for high performance." Progress in Polymer Science, vol. 32, no. 3, 2007, pp. 352–418.

💬 Final Thought:
The next time you run your hand over a smooth, eco-friendly tabletop or slip on a pair of sustainable sneakers, remember—there’s likely a molecule of SABIC TDI-80 in there, quietly doing its job, one dispersed particle at a time.

And no, it doesn’t want applause. Just proper ventilation. 😉

Sales Contact : sales@newtopchem.com
=======================================================================

ABOUT Us Company Info

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.

=======================================================================

Contact Information:

Contact: Ms. Aria

Cell Phone: +86 - 152 2121 6908

Email us: sales@newtopchem.com

Location: Creative Industries Park, Baoshan, Shanghai, CHINA