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PRIMID powder coatings have environmentally friendly characteristics, including being non-toxic and free from hazardous labels. They replace TGIC curing agents that carry potential physiological toxicity risks and have become a mainstream green solution for outdoor weather-resistant powder coatings.

This article systematically introduces the concept, characteristics, functions, applications, selection considerations, and common problem-solving measures of PRIMID powder coatings. It focuses on the applications of PRIMID powder coatings to help you better understand what PRIMID powder coatings are, as well as their characteristics and functions.

What Is PRIMID Powder Coating

PRIMID powder coating is a weather-resistant polyester powder coating system that uses β-hydroxyalkylamide (HAA) compounds as curing agents.

HAA curing agents have non-toxic toxicological characteristics and, unlike traditional TGIC curing agents, are not classified as irritating or potentially carcinogenic substances. Therefore, they are considered a safer and more environmentally friendly alternative solution.

Characteristics of PRIMID Powder Coating

The main characteristics of PRIMID powder coatings are as follows:

(1) High Environmental Performance

It uses non-toxic HAA curing agents, providing a green alternative to TGIC systems with physiological toxicity risks and meeting strict environmental regulations.

(2) Excellent Weather Resistance

The coating has excellent gloss and color retention performance and can pass architectural weather resistance standards such as Qualicoat, making it suitable for long-term outdoor exposure environments.

(3) Good Application Performance

It provides high electrostatic powder transfer efficiency and has a relatively wide curing window (usually 180℃/15-20min), making it suitable for automated production lines.

Functions of PRIMID Powder Coating

The specific functions of PRIMID powder coatings are as follows:

1. Outdoor Weather Protection Function

Its primary purpose is to provide long-term protection for outdoor metal substrates.

The coating has excellent UV resistance and gloss/color retention performance, effectively resisting sunlight and rain exposure, preventing chalking, fading, and gloss loss over several years.

It is widely used in architectural aluminum profiles, outdoor furniture, agricultural machinery equipment, and other applications.

2. Decorative and Corrosion Protection Functions

Decoration:

It can provide rich colors and finishes such as smooth surfaces and textured effects, enhancing product appearance.

Corrosion Protection:

The dense coating structure blocks moisture and corrosive media, preventing metal corrosion.

Comparison Between PRIMID Powder Coating and TGIC Powder Coating

Comparison Between PRIMID Powder Coating and TGIC Powder Coating

Main Item	PRIMID (HAA System)	TGIC System
Environmental Protection and Safety	Non-toxic, without hazardous labels, complying with mainstream environmental regulations.	Has physiological toxicity and is classified as a hazardous substance, facing usage restrictions.
Weather Resistance	Excellent performance; some studies show that long-term gloss retention may even be slightly better than TGIC.	Excellent performance and is a mature system proven through long-term application.
Mechanical Properties	The coating film usually has better flexibility and higher strength. Some studies indicate potentially better impact resistance.	The coating film is usually more rigid. Overall performance is good.
Thick Film Pinholing Resistance	A significant limitation exists. Water molecules are released during curing, making pinholes likely when film thickness exceeds 80-100μm.	Significant advantage. No by-products are produced during curing, allowing thick coatings (>170μm) without pinholes.
High Temperature Yellowing Resistance	Relatively weaker. Yellowing may occur during high-temperature baking (over-baking).	Significant advantage. Better color stability under high-temperature baking conditions.
Application and Processing	Electrostatic spraying transfer efficiency is usually better. However, the curing window is slightly narrower and requires stricter process control.	Manufacturing and curing processes are more tolerant and easier to control. Low-temperature curing is possible (as low as 130-145℃).
Cost	Good cost performance. Raw material cost is usually lower than TGIC.	Raw material cost is relatively higher.

 

How to Select PRIMID Powder Coating

When selecting PRIMID powder coatings, we often face uncertainty about how to choose the right product. Based on our industry experience, we recommend focusing on the following aspects when selecting PRIMID powder coatings.

1. Consider Environmental Compliance Requirements

The prerequisite for choosing PRIMID:

If products are exported to strict markets such as the European Union and the United States, or customers require non-toxic, non-hazardous labeling, and REACH/FDA compliance, PRIMID is the preferred choice.

TGIC systems are gradually being phased out in these applications.

2. Consider Coating Thickness Requirements

(1) Film Thickness ≤80μm

(Most architectural profiles and outdoor furniture)

→ PRIMID is fully suitable, offering good cost performance and significant environmental advantages.

(2) Film Thickness >80μm or Even 100μm+

(Such as heavy-duty corrosion-resistant pipelines and thick-coated workpieces)

→ PRIMID should be selected carefully. Water release during curing may cause pinholes. TGIC systems or specially formulated thick-film HAA systems should be considered first.

3. Consider Curing Equipment and Process

(1) Electric Heating Oven

→ PRIMID is suitable with low yellowing risk.

(2) Gas/Fuel Heating Oven

(Local overheating in high-temperature areas)

→ PRIMID is more prone to yellowing. Confirm whether precise temperature control is available or select special anti-yellowing HAA grades. Otherwise, TGIC systems are recommended.

(3) Curing Temperature Window

Typical PRIMID curing condition:

180℃ × 15~20min

If the production line can only provide low-temperature curing (<160℃) or short curing time, compatibility must be verified.

4. Consider Performance Priorities

(1) High Flexibility/Impact Resistance Requirements

(Such as automotive wheels)

→ PRIMID systems generally provide better flexibility than TGIC and can be considered first.

(2) Extreme Humid and Hot Environments

(Such as coastal high salt spray environments and Southeast Asian climates)

→ TGIC has more stable classic weather resistance. PRIMID requires high-weather-resistance formulations.

(3) Cost Control

PRIMID raw material costs are usually lower than TGIC, making it suitable for budget-sensitive projects.

Common Problems and Solutions of PRIMID Powder Coating

The most common problems during the use of PRIMID powder coatings are mainly reflected in the following aspects. Based on our industry experience, we provide corresponding solutions to help effectively solve powder coating problems you may encounter.

1. Pinholes Problem

Phenomenon:

Small holes appear on the coating surface, especially noticeable in thick coatings (>80μm).

Cause:

The curing reaction releases water molecules, and excessive film thickness prevents timely moisture escape.

Solutions:

① Control film thickness ≤80μm;

② Select thick-film HAA formulations (with moisture-release additives);

③ Adjust curing curves (lower temperature and longer curing time to allow gradual moisture release).

2. High Temperature Yellowing Problem

Phenomenon:

The coating turns yellow, especially obvious in light colors and white coatings.

Cause:

The molecular structure of HAA curing agents oxidizes and decomposes at high temperatures. Trace NOx gases in gas ovens accelerate yellowing.

Solutions:

① Precisely control temperature to avoid local overheating;

② Select anti-yellowing PRIMID formulations (with antioxidants/UV absorbers);

③ Electric ovens are preferred over gas ovens;

④ Reduce curing temperature (such as 160℃×20min, after performance verification).

3. Poor Leveling/Severe Orange Peel Problem

Phenomenon:

The surface shows obvious orange peel texture, low gloss, and poor DOI.

Cause:

Incorrect resin/curing agent ratio, uneven extrusion mixing, poor spray atomization, or excessively rapid curing heating.

Solutions:

① Optimize leveling additives;

② Check extruder screw wear to ensure uniform dispersion;

③ Adjust spraying parameters (atomizing pressure and voltage);

④ Use step heating to avoid excessive temperature during initial curing.

4. Poor Adhesion/Coating Peeling Problem

Cause:

Incomplete pretreatment (insufficient degreasing/phosphating), insufficient curing, or powder moisture absorption.

Solutions:

① Strictly implement pretreatment processes (pass water break test);

② Verify curing temperature (actual workpiece temperature ≥180℃×15min);

③ Fully warm powder before use to prevent moisture absorption (storage humidity <50%).

5. Batch Color Difference Problem

Cause:

The HAA system is sensitive to pigment/filler dispersion. Bonding process or extrusion temperature fluctuations affect color consistency.

Solutions:

① Strictly control extrusion temperature (avoid color changes);

② Retain standard color samples during each color adjustment and monitor ΔE≤1.0 with a color difference meter;

③ Fix recycled powder mixing ratio (≤10%~20%).

6. Storage Caking/Poor Flowability Problem

Cause:

HAA curing agents are hygroscopic. Moisture absorption reduces the powder glass transition temperature (Tg).

Solutions:

① Use sealed packaging and store in a cool, dry environment (<30℃, humidity <60%);

② Follow the first-in-first-out principle to avoid long-term storage;

③ Slightly caked powder can be tested after sieving, while severely caked powder should be discarded.

If you encounter difficult problems during the use of PRIMID powder coatings, 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 can provide you with a professional and reliable reference related to 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 you with more detailed product information, demonstration videos, or customized solutions to help you fully understand the functions and advantages of our products.