HAA · Hydroxyalkylamide Curing Agent
Low-toxicity, environmentally friendly curing agent for polyester powder coatings with excellent outdoor weatherability.
1. Product Information
2. Description
HAA (Hydroxyalkylamide) is a compound containing hydroxyalkylamide groups. It is an excellent curing agent for weather-resistant polyester powder coatings. Compared to TGIC, which is widely used globally, HAA offers lower toxicity, no skin irritation, and faster curing speed. Powder coatings produced with HAA exhibit outstanding outdoor performance, making it a truly green and environmentally friendly product.
3. Technical Specification
| Property | Specification |
|---|---|
| Appearance | White to pale yellow powder |
| Hydroxyl Equivalent | 82 ± 2 g/eq |
| Melting Range | 120 – 130 ℃ |
| Volatiles | ≤ 1.0% |
4. HAA vs TGIC Performance Comparison
5. Application
HAA is primarily used as a curing agent for polyester powder coatings, suitable for the following applications:
- Exterior durable powder coatings (windows, doors, aluminum profiles, railings)
- Home appliances and air conditioner housings
- Traffic facilities and municipal engineering (street lamps, traffic signs, guardrails)
- General industrial metal coatings
- Powder coating systems requiring low toxicity and environmental compliance
The manufacturing process for HAA systems is generally similar to other powder coatings. However, to enhance HAA dispersion, extrusion temperature should be slightly higher, approximately 115 – 120℃.
6. Use Level
For polyester resins with acid value in the range of 30 – 35 mg KOH/g, the recommended dosage of HAA is 5 – 6% of the polyester resin weight.
Dosage reference table:
| Resin Acid Value (mgKOH/g) | Suggested Ratio (Polyester / HAA) |
|---|---|
| 18 – 25 | 96.0 / 4.0 |
| 27 – 32 | 95.5 / 4.5 |
| 32 – 38 | 94.5 / 4.5 |
| 50 – 55 | 92.5 / 7.5 |
7. Curing Conditions
Recommended curing conditions:
- 180℃ / 10 – 15 minutes
- 190℃ / 10 – 12 minutes
- 160℃ / 12 minutes (low-temperature fast cure systems)
- New-generation HAA systems can achieve cure as low as 138℃ / 20 minutes with optimized polyester formulations
8. Recommended Formulations
8.1 Glossy White Powder Coating (Reference Formulation)
| Component | Parts by Weight |
|---|---|
| Uralac® P 3214 (Polyester Resin) | 623.3 |
| HAA Curing Agent | 32.9 |
| Titanium Dioxide | 330.0 |
| Flow Agent | 10.0 |
| Benzoin (Degassing Agent) | 2.8 |
| Total | 1000.0 |
Curing Conditions: 160℃ / 12 minutes or 180℃ / 6 minutes
Coating Thickness: ≈ 60 µm
Source: Covestro Uralac® P 3214 starting formulation
8.2 HAA-Cured Polyester Powder Coating Formulation Range
| Component | Parts by Weight |
|---|---|
| HAA-Specific Polyester Resin | 50 – 60 |
| HAA Curing Agent | 3 – 7 |
| Pigments & Fillers | 30 – 50 |
| Additives (Flow agent, degassing agent, etc.) | As required |
9. Packaging
Polyethylene-lined kraft paper bags. Net weight 25kg per bag.
10. Storage
Store in a dry and cool place, protected from moisture and direct sunlight. This product is hygroscopic; reseal bags immediately after use. Shelf life is 1 year under normal storage conditions.
11. Toxicity & Safety Measures
HAA exhibits approximately 1/12.5 the acute oral toxicity of TGIC (mouse oral LD₅₀: HAA 5.0 g/kg vs. TGIC 0.4 g/kg) and is Ames-negative (non-mutagenic), while TGIC is Ames-positive. HAA is not classified as a hazardous substance and does not require hazard labeling. It shows low irritation to skin and eyes. Standard industrial hygiene practices are recommended during handling.
12. Disclaimer
No condition or warranty is to be assumed from the foregoing information. This information and all further technical advice is based on our present knowledge and experience. However, it implies no liability or other legal responsibility on our part, including with regard to existing third-part intellectual property rights, especially patent rights. In particular, no warranty, whether express or implied, or guarantee of product properties in the legal sense is intended or implied. We reserve the right to make any changes according to technological progress or further developments.
The customer is not released from the obligation to conduct careful inspection and testing of incoming goods. Performance of the product described herein should be verified by testing, which should be carried out only by qualified experts in the sole responsibility of a customer. Reference to trade names used by other companies is neither a recommendation, nor does it imply that similar products could not be used.
Key Facts
HAA (hydroxyalkylamide; chemical name N,N,N',N'-tetrakis(2-hydroxyethyl)adipamide, CAS 6334-25-4) is a low-toxicity curing agent for polyester powder coatings and the ideal alternative to TGIC, manufactured by Huangshan Deping Chemical Co., Ltd. Its EINECS number is 228-711-6, its molecular formula is C14H28N2O6, and its molecular weight is 320.38 g/mol. HAA is a white to pale yellow powder with a melting range of 120-130 °C, a hydroxyl equivalent of 82 ± 2 g/eq, and volatiles of at most 1.0%.
For polyester resins with an acid value of 30-35 mg KOH/g, the recommended dosage of HAA is 5-6% of the polyester resin weight. Recommended curing conditions are 180 °C for 10-15 minutes or 190 °C for 10-12 minutes. HAA cannot directly replace TGIC in conventional TGIC polyester systems; HAA-specific polyester resins (acid value 30-35) must be used. Because HAA curing releases water, pinholes may occur in thick films above about 80 µm, and the extrusion temperature for HAA systems should be slightly higher, about 115-120 °C.
Frequently Asked Questions
What is HAA and how does it compare with TGIC?
HAA (hydroxyalkylamide, CAS 6334-25-4) is a curing agent for polyester powder coatings. Compared with TGIC it has lower toxicity (oral LD50 about 5.0 g/kg in mice, no skin irritation, Ames-negative), faster curing, inherent tribo-chargeability for friction guns, and lower formulation cost, making it the ideal TGIC alternative.
How much HAA should be used?
For polyester resins with an acid value of 30-35 mg KOH/g, use HAA at 5-6% of the polyester resin weight. The ratio depends on the resin acid value; for example, acid value 27-32 corresponds to a polyester/HAA ratio of about 95.5/4.5.
Can HAA directly replace TGIC in an existing formulation?
No. HAA cannot be directly substituted for TGIC in conventional TGIC polyester systems. HAA-specific polyester resins with an acid value of 30-35 mg KOH/g must be selected.
What are the curing conditions for HAA?
Recommended curing conditions are 180 °C for 10-15 minutes and 190 °C for 10-12 minutes; low-temperature fast-cure systems can cure at 160 °C for 12 minutes.
What should be noted for thick HAA coatings?
HAA curing releases water as a by-product, so pinholes may occur in thick coatings above about 80 µm. Formulators should control film thickness accordingly, and keep benzoin levels low, as HAA systems are sensitive to excess benzoin, which may cause yellowing.