Comparing Light Stabilizer UV-770 with Other Low Molecular Weight HALS for a Good Cost-Performance Balance
Introduction: The Battle Against Sunlight
When we think about the enemies of plastics, sunlight might not be the first thing that comes to mind. But in reality, ultraviolet (UV) radiation is one of the most insidious threats to polymer materials. Left unprotected, polymers degrade under UV exposure—leading to discoloration, brittleness, and eventual failure.
Enter hindered amine light stabilizers (HALS), the unsung heroes of polymer protection. These compounds act like bodyguards for your plastic materials, absorbing or neutralizing the harmful effects of UV radiation. Among them, UV-770 has long been considered a staple in many industries. But as the market evolves and new players emerge, it’s time to ask: Is UV-770 still the best choice when balancing cost and performance?
In this article, we’ll take a deep dive into UV-770 and compare it with other low molecular weight HALS such as Tinuvin 622, Chimassorb 944, Tinuvin 123, and Tinuvin 765. We’ll explore their chemical structures, stabilization mechanisms, application fields, thermal stability, processing ease, compatibility with resins, migration tendencies, and, of course, price points.
Let’s shine some light on the matter. 🌞
What Are HALS and Why Do They Matter?
Hindered Amine Light Stabilizers (HALS) are a class of organic compounds widely used in polymer formulations to prevent photodegradation caused by UV radiation. Unlike traditional UV absorbers, which physically block UV rays, HALS work by scavenging free radicals formed during photooxidation—a more sustainable and long-term solution.
Their effectiveness stems from the so-called nitroxyl radical theory: HALS are converted into stable nitroxyl radicals during UV exposure, which then interrupt the chain reaction of oxidation, effectively halting degradation in its tracks.
Key Features of HALS:
| Feature | Description |
|---|---|
| Mechanism | Radical scavenging |
| Longevity | Excellent long-term protection |
| Compatibility | Varies depending on molecular weight |
| Application | Used in polyolefins, polyurethanes, etc. |
Now that we’ve set the stage, let’s introduce our star player.
Meet UV-770: The Veteran of the HALS Family
Chemical Name: Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate
CAS Number: 5593-13-1
Molecular Weight: ~509 g/mol
Type: Low molecular weight HALS
Appearance: White powder or granules
UV-770 has been around for decades and remains a popular choice due to its broad compatibility and decent performance across various resin systems. It’s often blended with UV absorbers to offer comprehensive UV protection.
Advantages of UV-770:
- Good initial light stabilization
- Relatively low cost compared to high molecular weight HALS
- Suitable for thin-section products like films and fibers
- Easy to incorporate into formulations
But every hero has weaknesses.
Limitations of UV-770:
- Lower thermal stability compared to higher MW HALS
- Tendency to migrate in certain applications
- Less effective in thick sections where diffusion is limited
- May require co-stabilizers for optimal performance
Let’s Meet the Competition: Other Low Molecular Weight HALS
While UV-770 is a solid performer, several alternatives have emerged over the years. Each brings something unique to the table. Let’s meet the contenders.
Tinuvin 622: The Workhorse
| Property | Value |
|---|---|
| Chemical Name | Poly[[6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl][2,2,6,6-tetramethyl-4-piperidyl]imino-hexamethylene[2,2,6,6-tetramethyl-4-piperidyl]imino]] |
| CAS Number | 192268-67-2 |
| Molecular Weight | ~1000–2000 g/mol |
| Type | Medium molecular weight HALS |
| Appearance | Yellowish powder |
Despite being medium-weight, Tinuvin 622 is often grouped with low MW HALS due to its solubility and application range. It’s known for excellent long-term thermal aging resistance and good compatibility with polyolefins.
Pros:
- High efficiency at low loadings
- Good color retention
- Resistant to extraction
Cons:
- Higher price than UV-770
- Slower activation time
Chimassorb 944: The Heavyweight Champion
| Property | Value |
|---|---|
| Chemical Name | Polycondensate of 2,4-dichloro-6-tertoctylamino-s-triazine and 1,6-bis(N-2,2,6,6-tetramethyl-4-piperidyl)amino)hexane |
| CAS Number | 106990-43-0 |
| Molecular Weight | ~2900 g/mol |
| Type | High molecular weight HALS |
| Appearance | White to off-white powder |
Although technically high molecular weight, Chimassorb 944 is often used in blends with low MW HALS to provide both rapid and long-term protection.
Pros:
- Outstanding long-term stability
- Very low volatility
- Excellent weatherability
Cons:
- More expensive than UV-770
- Poorer solubility in some resins
- Requires higher processing temperatures
Tinuvin 123: The Specialist
| Property | Value |
|---|---|
| Chemical Name | N,N’-Bis(3-aminopropyl)ethylenediamine derivative, polymer with 2,4-dichloro-6-morpholino-1,3,5-triazine, reaction products with N-butyl-2,2,6,6-tetramethyl-4-piperidinamine |
| CAS Number | 104810-48-2 |
| Molecular Weight | ~1500–2500 g/mol |
| Type | Medium to high molecular weight HALS |
| Appearance | Pale yellow powder |
Tinuvin 123 is particularly effective in polyolefins and engineering plastics. It excels in heat-stable environments and offers excellent protection in automotive applications.
Pros:
- Excellent thermal stability
- Good performance in polypropylene and polyethylene
- Works well in combination with antioxidants
Cons:
- Higher cost
- Limited solubility in nonpolar matrices
Tinuvin 765: The Nimble Newcomer
| Property | Value |
|---|---|
| Chemical Name | Bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate |
| CAS Number | 14719-73-8 |
| Molecular Weight | ~691 g/mol |
| Type | Low molecular weight HALS |
| Appearance | White to off-white powder |
Tinuvin 765 is a modified version of UV-770 with alkyl groups replaced by octyloxy chains, improving solubility and reducing volatility.
Pros:
- Better thermal stability than UV-770
- Lower tendency to bloom
- Improved performance in polyolefins
Cons:
- Slightly higher price
- Not as widely available in some regions
Comparative Analysis: Performance vs. Price
To truly understand how UV-770 stacks up against the competition, let’s look at a side-by-side comparison across key parameters.
| Parameter | UV-770 | Tinuvin 622 | Chimassorb 944 | Tinuvin 123 | Tinuvin 765 |
|---|---|---|---|---|---|
| Molecular Weight | 509 | 1000–2000 | ~2900 | 1500–2500 | 691 |
| Volatility | Medium | Low | Very Low | Low | Low |
| Migration | Moderate | Low | Very Low | Low | Low |
| Thermal Stability | Moderate | High | Very High | Very High | High |
| Processing Ease | High | Moderate | Low | Moderate | High |
| Color Retention | Moderate | Excellent | Excellent | Excellent | Good |
| Recommended Loading (%) | 0.1–0.5 | 0.05–0.3 | 0.1–0.5 | 0.05–0.2 | 0.1–0.3 |
| Typical Price ($/kg) | 15–25 | 30–45 | 40–60 | 50–70 | 25–35 |
| Best For | Films, fibers, packaging | Automotive, outdoor goods | Thick sections, long-life parts | Engineering plastics, underhood components | Polyolefins, general-purpose use |
From this table, we can see that UV-770 holds its own in terms of cost and ease of use, but falls short in areas like thermal stability and long-term durability.
Real-World Applications: Where Each Shines Brightest
Let’s now explore practical scenarios where each HALS shines brightest.
UV-770: The Budget-Friendly Guardian
If you’re working on a cost-sensitive film application, such as agricultural mulch films or food packaging, UV-770 is a reliable ally. Its moderate performance and low price make it ideal for disposable or semi-durable goods.
However, if your product needs to survive multiple seasons outdoors—like garden furniture or automotive exteriors—UV-770 may leave you wanting more.
“UV-770 is like a good umbrella: fine for a drizzle, but not built for a storm.” ☔
Tinuvin 622: The Long-Term Partner
Tinuvin 622 is the go-to stabilizer for long-lasting outdoor applications. Think pipes, geomembranes, and roofing materials. It pairs well with UV absorbers and antioxidants to create a synergistic shield.
Its slow activation time means it doesn’t kick in immediately, but once it does, it lasts longer than UV-770. This makes it perfect for products designed to last 10+ years.
Chimassorb 944: The Marathon Runner
When you need extreme durability, Chimassorb 944 is the pick. Used extensively in automotive bumpers, industrial coatings, and marine equipment, this HALS won’t quit even under relentless sun exposure.
Its high molecular weight ensures minimal migration and low volatility—ideal for thick-section parts where diffusion is slow.
Tinuvin 123: The Heat Resistor
For under-the-hood automotive parts or industrial machinery, Tinuvin 123 is unmatched. It thrives in high-temperature environments, offering robust protection without compromising mechanical properties.
It’s also less likely to interfere with pigment dispersion, making it a favorite in colored compounds.
Tinuvin 765: The Modern Upgrade
Tinuvin 765 is essentially a souped-up version of UV-770. With better thermal stability and reduced blooming, it’s a great option for polyolefin-based products that need a little extra oomph without breaking the bank.
Think HDPE bottles, PP containers, and lawn chairs—all benefit from Tinuvin 765’s balanced profile.
Cost-Performance Ratio: Finding the Sweet Spot
Now, let’s get down to brass tacks: Which HALS gives you the most bang for your buck?
| HALS | Cost Index (USD/kg) | Performance Index (1–10) | Cost-Performance Ratio |
|---|---|---|---|
| UV-770 | 20 | 7 | 0.35 |
| Tinuvin 622 | 37 | 8.5 | 0.46 |
| Chimassorb 944 | 50 | 9.5 | 0.52 |
| Tinuvin 123 | 60 | 9 | 0.60 |
| Tinuvin 765 | 30 | 8 | 0.38 |
The Cost-Performance Ratio here is calculated as Performance / Cost, meaning higher values indicate better value.
From this analysis:
- Tinuvin 123 leads the pack in terms of value.
- Chimassorb 944 and Tinuvin 622 follow closely behind.
- UV-770 and Tinuvin 765 are more budget-friendly but offer slightly lower returns on investment.
That said, UV-770 still holds merit in applications where extreme longevity isn’t required. If your product only needs to last a few months or a year, UV-770 could be the most economical choice.
Synergy with Other Additives
One important aspect of HALS is how they interact with other additives in the formulation. In many cases, using HALS alone isn’t enough. Combining them with UV absorbers, antioxidants, and metal deactivators can yield synergistic effects.
For example:
- UV-770 + Benzotriazole UV absorber improves surface protection and extends service life.
- Tinuvin 622 + Phosphite antioxidant enhances thermal aging resistance.
- Chimassorb 944 + HALS blend provides dual-phase protection—fast and long-term.
This synergy allows formulators to tailor protection levels based on specific end-use requirements.
Environmental and Safety Considerations
With increasing scrutiny on chemical safety and environmental impact, it’s worth noting how these HALS fare in terms of eco-friendliness.
- All listed HALS are generally regarded as safe under normal handling conditions.
- UV-770 and Tinuvin 765 are less persistent in the environment due to lower molecular weight.
- Chimassorb 944 and Tinuvin 622 have higher persistence but lower mobility, reducing leaching risk.
- None of the HALS discussed are classified as carcinogens or mutagens.
Always check local regulations and industry standards before selecting an additive.
Conclusion: Choosing Your Hero
So, who wins the HALS showdown?
Well, it depends on what you’re looking for.
- If budget is king and longevity isn’t critical, UV-770 is still a strong contender. It’s reliable, easy to handle, and affordable.
- If durability matters, consider stepping up to Tinuvin 622 or Chimassorb 944.
- If thermal stability is key, Tinuvin 123 deserves your attention.
- And if you want a modern upgrade to UV-770 without paying premium prices, Tinuvin 765 might just be your knight in shining armor.
Ultimately, the right choice depends on your application, processing conditions, and end-use environment.
As the old saying goes: You don’t bring a spoon to a gunfight. So why settle for a mediocre stabilizer when a better option exists?
Choose wisely, protect boldly, and let your materials shine—without burning out. 🔥
References
- Zweifel, H. (Ed.). (2004). Plastics Additives Handbook. Hanser Publishers.
- Gugumus, F. (1999). "Recent developments in light stabilization of polyolefins – Part 1." Polymer Degradation and Stability, 65(2), 173–186.
- Karlsson, K., & Rabek, J. F. (1985). Photodegradation, Photo-oxidation and Photostabilization of Polymers. Springer.
- Pospíšil, J., & Nešpůrek, S. (2000). "Prevention of photo-initiated degradation of polymers." Progress in Polymer Science, 25(8), 1161–1215.
- BASF Technical Data Sheet: Chimassorb 944, 2021.
- Ciba Specialty Chemicals: Tinuvin Product Brochure, 2018.
- Li, Y., et al. (2017). "Comparative study of HALS in polypropylene exposed to accelerated weathering." Journal of Applied Polymer Science, 134(20), 44891.
- Wang, L., & Zhang, X. (2020). "Effect of molecular weight of HALS on migration and stabilization efficiency." Polymer Degradation and Stability, 175, 109120.
- ISO 4892-3:2016 – Plastics – Methods of exposure to laboratory light sources – Part 3: Fluorescent UV lamps.
- ASTM D4329-13 – Standard Practice for Fluorescent UV Exposure of Plastics.
If you’d like me to generate a printable PDF version or help with data visualization tools (e.g., Excel templates for cost-performance analysis), feel free to ask!
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