Polyester TGIC Powder Coating: Characteristics, Benefits, Applications, and Selection Tips
News 2026-07-30
TGIC powder coating provides outdoor metals with top-level weather-resistant protection and decorative performance. It is mainly applied in fields such as aluminum profiles, automotive components, appliance housings, and building facilities that are exposed to outdoor environments for long periods.
This article systematically introduces the concept, characteristics, functions, transparency principles, application fields, selection considerations, and common problem-solving measures of TGIC powder coating. It focuses on the functions of TGIC powder coating to help readers better understand what TGIC powder coating is, as well as its characteristics and application fields.
What is TGIC Powder Coating
TGIC powder coating is a thermosetting powder coating that uses carboxyl polyester resin as the main film-forming material and triglycidyl isocyanurate (TGIC) as the curing agent, forming a coating film through cross-linking reactions.
TGIC is a heterocyclic epoxy compound containing three epoxy groups. As a curing agent, the three epoxy groups in its molecular structure can undergo high-density cross-linking reactions with the carboxyl groups at the ends of polyester resin molecular chains, forming a dense three-dimensional network structure.
Characteristics of TGIC Powder Coating
The main characteristics of TGIC powder coating are as follows:
- Excellent Outdoor Weather Resistance
This is its most important advantage.
Because the TGIC curing agent molecule contains a stable triazine ring structure, the coating has extremely strong UV resistance. Even under long-term outdoor exposure, it is not easy to chalk or fade, making it the preferred choice for outdoor products such as aluminum profiles, outdoor furniture, and automotive components.
- Balanced Mechanical and Chemical Properties
With high cross-linking density, the coating provides excellent adhesion, hardness, and flexibility (such as passing a ≤3mm bending test).
It also demonstrates good chemical resistance (acid/alkali/solvent resistance) and heat resistance (up to approximately 250℃).
- Key Limitation: Toxicity Issue of TGIC
TGIC is classified by regions such as the European Union (REACH regulations) as a Category 1 reproductive toxic substance, presenting occupational health risks.
Therefore, in regions with strict environmental regulations, its application is gradually being replaced by non-toxic or low-toxicity alternative systems such as HAA (hydroxyalkylamide).
Functions of TGIC Powder Coating
The main functions of TGIC powder coating are reflected in the following aspects:
- Weather Protection Function
Relying on the stable triazine ring structure in TGIC curing agent molecules, the coating can strongly resist UV aging.
It effectively prevents outdoor metal components (such as aluminum profiles and guardrails) from chalking, fading, and gloss loss caused by sunlight and rain exposure, significantly extending service life.
- Physical and Chemical Protection Function
The coating film is dense and provides excellent adhesion, impact resistance, and flexibility.
It can withstand wind and sand impacts and minor collisions. At the same time, it has resistance to acid rain and chemical corrosion, protecting the substrate from damage.
- Decorative and Appearance Enhancement Function
It can achieve various effects such as high gloss, matte, textured, and metallic finishes, meeting the high requirements for color and texture in outdoor buildings and automotive components, achieving both protection and aesthetics.
Application Fields of TGIC Powder Coating
TGIC powder coating is mainly applied to metal products that are exposed to outdoor environments for long periods and require strict weather resistance. The specific application fields are as follows:
- Architectural Aluminum Profile Field
It is used for surface coating of outdoor aluminum materials such as doors, windows, curtain walls, guardrails, and shutters.
It replaces anodizing processes, providing rich colors and excellent weather resistance, with a service life warranty of more than 10 years.
- Automotive and Transportation Fields
It is used for automotive components such as wheel rims, roof racks, rearview mirror housings, and commercial vehicle compartments.
It protects against UV radiation, acid rain, and deicing salt corrosion.
- Outdoor Facilities and Furniture Fields
It is used for facilities exposed to long-term sunlight and rain, including park/community fitness equipment, outdoor tables and chairs, street light poles, traffic guardrails, and photovoltaic supports.
- Appliance and General Industrial Fields
It is used for products requiring outdoor climate resistance, such as outdoor air conditioner housings, solar water heater supports, and agricultural machinery.
How to Select TGIC Powder Coating
When selecting TGIC powder coating, we often do not know how to choose. Based on our industry experience, we recommend focusing on the following aspects when selecting outdoor furniture powder coating.
- Consider the Application Environment
(1) Outdoor Applications
For outdoor applications (such as aluminum profile doors and windows, automotive wheel rims, outdoor furniture, and guardrails), TGIC systems are the preferred choice.
Their excellent weather resistance cannot be replaced by other systems.
(2) Indoor Applications
For indoor applications (such as appliance internal housings and indoor furniture), TGIC is not recommended.
The cost is too high, and its toxicity risk is unnecessary. Epoxy or epoxy-polyester hybrid systems are more economical choices.
- Balance Performance and Environmental Requirements
After selecting outdoor applications, a balance must be made between ultimate performance and environmental compliance:
(1) Select TGIC System
Suitable for applications pursuing top-level surface effects (high gloss and excellent leveling) and thick coating films (reduced pinhole risk).
Suitable when products are not exported to the European Union and environmental pressure is relatively lower.
It is also suitable where higher heat resistance is required (up to 250℃).
(2) Select HAA System
Suitable for products exported to the European Union or customers with clear environmental certification requirements (such as REACH).
It is suitable for applications requiring zero tolerance for toxicity and pursuing excellent occupational health and safety.
The trade-off is that surface effects are slightly inferior to TGIC systems, thick coatings may have pinhole issues, and heat resistance is slightly lower.
- Other Considerations
(1) Resin Ratio
TGIC needs to be combined with carboxyl polyester resin. The typical ratio is approximately 7%-8% of the polyester resin amount.
(2) Curing Conditions
The conventional curing condition is 180-200℃/10-15 minutes. If the production line focuses on energy saving, low-temperature curing formulations can be selected.
Common Problems and Solutions of TGIC Powder Coating
The most common problems during the use of TGIC powder coating are mainly reflected in the following aspects. Based on our industry experience, we propose corresponding solutions to help effectively solve powder coating problems you may encounter.
- Orange Peel and Poor Leveling Problems
Causes:
Improper powder particle size distribution or poor inherent leveling performance.
Excessive roughness of the pretreatment coating layer.
Improper spraying parameters (voltage/atomizing air pressure).
Solutions:
Select formulations with better leveling performance.
Control pretreatment processes (such as dense and uniform sandblasting/phosphating films).
Optimize spraying voltage (60-90kV) and atomizing air pressure.
- Small Surface Holes in Coating Film
Causes:
Excessive coating thickness in one spraying process (electrostatic breakdown).
Residual moisture or volatile substances from pretreatment escaping during curing.
Powder absorbs moisture.
Solutions:
Control film thickness and avoid excessive single spraying thickness (recommended <120μm).
Strengthen pretreatment drying processes.
Store powder in a cool and dry environment (<30℃).
- Coating Peeling and Cracking Problems
Causes:
Insufficient curing (insufficient temperature/time).
Oil contamination or oxide scale on the workpiece surface.
Pretreatment quality does not meet requirements.
Expired powder.
Solutions:
Confirm the actual heating temperature and time of the workpiece rather than only checking the oven temperature display.
Strengthen pretreatment (degreasing, acid washing, phosphating).
Use coatings within the shelf life.
- Chalking and Fading After Outdoor Exposure
Causes:
Incorrect ratio between resin and TGIC in the formulation (such as insufficient TGIC content).
Selection of non-outdoor-grade pigments (such as ordinary pigments with poor UV resistance).
Insufficient curing degree.
Solutions:
Ensure accurate TGIC addition amount in the formulation (usually 7%-8% of polyester resin).
Select high weather-resistant pigments (such as rutile titanium dioxide).
Ensure complete curing.
- Color Deviation from Standard Problems
Causes:
Excessive curing temperature or excessive curing time (over-baking).
Insufficient heat resistance of pigments.
Solutions:
Strictly follow the process window and regularly calibrate the oven temperature curve.
Select pigments with better heat resistance.
- Powder Agglomeration and Spray Gun Blockage Problems
Causes:
Storage temperature is too high or powder absorbs moisture.
Recycled powder is mixed with impurities without screening.
The glass transition temperature (Tg) of the powder itself is too low.
Solutions:
Store in a cool environment below 30℃ and avoid compression.
Pass recycled powder through an 80-100 mesh screen and mix with new powder according to the proper ratio.
Select formulations with suitable Tg.
If you encounter difficult problems during the use of TGIC powder coating, please feel free to contact us at any time to obtain professional technical support, discuss solutions together, and promote the development of the powder coating industry.
We hope this article provides you with a professional and reliable reference regarding the powder coating industry. We sincerely welcome your inquiries regarding powder coating product performance, industry standards, application methods, precautions, or any related questions. Please feel free to contact us through messages or direct communication so that we can provide more detailed product information, demonstration videos, or customized solutions to help you fully understand the functions and advantages of our products.
