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Wrinkle powder coating forms three-dimensional and uniform wrinkle textures on metal surfaces, featuring excellent hiding power and decorative performance. It is widely used in products such as office furniture (filing cabinets, safes), instrument housings, and radiators.

This article systematically introduces the concept, characteristics, functions, formation principle, application fields, selection considerations, and common problem-solving measures of wrinkle powder coating. It focuses on the functions of wrinkle powder coating, helping people better understand what wrinkle powder coating is, as well as its characteristics and applications.

What Is Wrinkle Powder Coating

Wrinkle powder coating is an artistic powder coating that can spontaneously form three-dimensional and regular wrinkle textures during the high-temperature curing process through special formulation design.

The coating surface is not flat but covered with uniform raised and recessed patterns, resembling folds on fabric or ripples on water. Therefore, it is also known in the industry as “soft texture paint” or “water ripple powder coating”.

Characteristics of Wrinkle Powder Coating

The main characteristics of wrinkle powder coating are as follows.

1. Unique Three-Dimensional Aesthetic Effect

The coating surface is not flat but covered with uniform raised and recessed patterns, resembling folds on fabric or water ripple textures. Therefore, it is also called “soft texture paint” or “water ripple powder coating”.

2. Various Texture Effects

By adjusting the formulation and process, various effects ranging from large wave patterns to fine wrinkle textures can be achieved. The size and fineness of the texture are closely related to the powder flowability and the amount of texture agent added in the formulation. Powders with good flowability tend to form larger textures, while powders with poor flowability tend to form finer and denser textures.

3. Wide Range of Colors and Gloss Levels

It can achieve a full range of colors and allows adjustment from bright gloss to soft gloss or even matte finishes, meeting different product design requirements.

4. Mechanical Performance and Corrosion Resistance

The coating is strong and durable, providing excellent mechanical properties (such as impact resistance and flexibility) and corrosion resistance.

5. Strong Hiding Ability for Substrate Defects

Its three-dimensional texture can effectively cover surface defects such as roughness, scratches, and sand holes on workpieces. Therefore, it is especially suitable for castings, die-cast parts, and other workpieces with high surface appearance requirements.

6. Customizable Outdoor Weather Resistance

According to application requirements, it can be divided into indoor and outdoor types. Outdoor types use hydroxyl-terminated polyester resin combined with special curing agent systems to achieve excellent weather resistance and aging resistance.

Functions of Wrinkle Powder Coating

The functions of wrinkle powder coating are mainly reflected in the following aspects.

1. Decorative Function: Beautification and Concealment

This is its most important application value.

(1) Providing Unique Three-Dimensional Texture

It can give the coating a unique three-dimensional appearance and texture, similar to fabric wrinkles or water wave patterns, meeting the requirements of office furniture, instruments, and other products for aesthetics and individuality.

(2) Effectively Covering Substrate Defects

Its uneven texture can effectively cover defects such as sand holes, scratches, and rough surfaces on workpieces, improving the product appearance qualification rate. This is also why it is commonly used for castings and die-cast parts.

2. Protective Function: Protection and Weather Resistance

While providing texture effects, it also has the conventional protective functions of powder coatings.

(1) Physical Protection

The coating is strong and provides certain impact resistance, flexibility, and adhesion, protecting metal substrates from daily wear and scratches.

(2) Chemical Protection

By selecting an appropriate resin system, it can provide corrosion resistance and outdoor weather resistance, resisting damage caused by ultraviolet radiation, moisture, and chemicals, thereby extending the service life of workpieces.

3. Other Functions

(1) Providing Anti-Slip Surfaces

Some wrinkle coating surfaces have high friction and can be used in applications requiring anti-slip performance.

(2) Creating Special Visual Effects

By adding metallic powders and other materials, sparkling wrinkle effects can be created, or artistic effects such as antique and aged appearances can be achieved.

(3) Simplifying Surface Treatment Processes

Due to its strong hiding ability, certain workpieces can reduce pre-treatment processes such as putty leveling, thereby lowering overall costs.

Formation Principle of Wrinkle Powder Coating

The principle of wrinkle powder coating is to utilize the difference in surface tension between different components and the curing rate gradient during the coating curing process. Under stress, the coating surface undergoes buckling deformation, eventually forming controllable three-dimensional wrinkle textures. The specific formation process can be described as follows:

1. Surface Tension-Driven Flow

The added wrinkle agent (such as CAB) is incompatible with the main resin and has a lower surface tension. During high-temperature melting, local surface tension differences drive coating flow, forming initial uneven textures.

2. Formation of a “Skin Layer” Through Curing Rate Gradient

During coating curing, the surface first cross-links to form a hard “mechanical skin layer”, while the interior is still undergoing molten flow. This difference between the surface and interior causes the skin layer to be compressed, generating compressive stress.

3. Stress Buckling Locks the Texture

When the compressive stress exceeds the critical value, the surface layer undergoes buckling deformation, forming the final wrinkle texture. As curing continues, the texture becomes permanently fixed.

Application Fields of Wrinkle Powder Coating

Wrinkle powder coating has a wide range of applications and is mainly used in the following fields:

1. Home Appliances

It is widely applied on the housings of home appliances such as refrigerators, washing machines, microwave ovens, and air conditioners, providing attractive and durable surfaces.

2. Furniture and Office Equipment

It is widely used for metal furniture (such as tables and chairs), filing cabinets, safes, storage racks, and other products. The three-dimensional texture improves product appearance, texture quality, and wear resistance.

3. Industrial Equipment and Electromechanical Products

This is its traditional advantage field, especially suitable for coating housings of electrical control cabinets, industrial sewing machines, instruments, and meters. It can effectively cover common surface defects of castings, such as roughness and sand holes.

4. Construction and Transportation Facilities

Outdoor weather-resistant wrinkle powder coating can be applied to aluminum alloy doors and windows, building curtain walls, highway guardrails, security doors, and other products. It combines decorative effects with long-term UV protection performance.

5. Vehicles and Hardware Accessories

It can be used for metal components of vehicles such as automobiles and motorcycles, as well as fire-fighting equipment, hardware tools, and other products, providing protective coatings with three-dimensional textures.

How to Select Wrinkle Powder Coating

When selecting wrinkle powder coating, we often do not know how to make the right choice. Based on our industry experience, we recommend focusing on the following aspects when selecting wrinkle powder coating.

1. Determine the Application Environment: Indoor or Outdoor

This is the primary decision factor and determines the basic coating system.

(1) Indoor Applications

Use epoxy/dicyandiamide systems or epoxy-polyester hybrid systems. They have relatively lower costs and are widely used for hardware, furniture, and internal components of electrical appliances. However, their weather resistance is relatively poor, making them unsuitable for long-term outdoor exposure.

(2) Outdoor Applications

Polyester/TGIC systems or polyester/TMMGU systems (hydroxyalkyl amide systems) must be selected. These coatings provide excellent UV resistance and aging resistance and are suitable for applications such as communication base station cabinets, engineering vehicles, and outdoor building materials.

2. Select Texture Effect and Size

The size, density, and three-dimensional appearance of wrinkle textures can be adjusted through formulations and additives.

(1) Amount of Texture Agent Is the Key Factor

This is the most direct factor controlling texture formation. Generally, when the amount of texture agent (such as floating pattern agent) added is low, larger and less distinct patterns are formed; when the amount increases, the patterns become smaller, denser, and clearer.

(2) Effect of Texture Agent Addition Amount

Some data indicate that when the addition amount is less than 0.035%, the patterns are very large but the substrate may easily become exposed. When the addition amount is between 0.05%–0.08%, the patterns become smaller and tend to stabilize.

(3) Influence of Additive Particle Size

The particle size of externally added texture agents (floating pattern agents) also affects pattern formation. Coarser particles produce larger patterns, while finer particles produce smaller patterns.

(4) Influence of Base Material Performance

For epoxy resin used in wrinkle powder production, a softening point ≥89℃ is recommended. A higher softening point results in poorer melt flowability, making it easier to produce stronger three-dimensional textures.

3. Evaluate Key Performance Indicators

High-quality wrinkle powder coating should meet the following core technical parameters to ensure coating durability:

(1) Coating Thickness

The coating thickness is usually between 60–120μm to balance texture appearance and protective performance.

(2) Adhesion

It should reach the highest standard of Grade 0 according to the cross-cut adhesion test.

(3) Impact Resistance

It is usually required to pass the forward/reverse impact test of 50kg·cm.

(4) Salt Spray Resistance

According to ASTM B117 standard, high-quality products can achieve 500–1000 hours without red rust.

4. Match Substrate and Coating Process

(1) Substrate Matching

Wrinkle powder coating is particularly suitable for workpieces with minor surface defects, such as castings and die-cast parts. Its texture can effectively cover surface imperfections.

For thin plates or thick plates, early products may have had texture formation issues affected by the heating rate during baking. However, improved formulations are now available that claim not to be affected by this limitation.

(2) Pre-treatment and Curing

The long-term adhesion of the coating depends on thorough pre-treatment (such as phosphating and ceramic coating treatment). At the same time, the curing oven temperature must be accurately controlled (usually within ±5℃) to ensure uniform texture consistency and complete coating cross-linking.

Common Problems and Solutions of Wrinkle Powder Coating

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

1. Floating Color Problem of Dark Wrinkle Powder Coating

Phenomenon:

The color of the dark coating surface is uneven, showing different shades of color spots or color differences.

Cause:

The main reasons are uneven surface tension of the coating surface and separation and migration between different pigments caused by differences in hydrophobicity. Poor pigment dispersion can also aggravate this problem.

Solutions:

(1) During production, use hydrophilic pigments as much as possible to reduce pigment migration.

(2) Select ultra-fine fillers with particle sizes greater than 1250 mesh to improve system dispersion uniformity.

(3) During mixing, pre-mix pigments and fillers evenly first, then add polyester resin. After adjusting the color to a similar shade, add the wrinkle agent.

(4) Add pigment dispersants and wetting agents to improve pigment compatibility.

2. Substrate Exposure Problem

Phenomenon:

The substrate is exposed at the recessed areas of the wrinkle texture, and the coating coverage is incomplete.

Cause:

The melting viscosity of the system is too high, resulting in poor coating flow and spreading performance; the gel time is too long (meaning the coating remains at high temperature for too long before curing), and after the molten coating flows away, it cannot flow back and fill the area.

Solutions:

(1) Adjust the formulation to reduce the melting viscosity of the system and improve flow and spreading performance.

(2) Strictly control the curing process and avoid excessively long preheating or heating times.

(3) Appropriately increase coating thickness while ensuring proper texture formation.

3. Uneven Texture or No Texture Formation Problem

Phenomenon:

The wrinkle size on the coating surface is inconsistent, unevenly distributed, or the wrinkle effect completely disappears.

Causes:

(1) Incorrect amount of wrinkle agent added:

When the amount is too low, the texture becomes large and unclear; when the amount is too high, the texture becomes finer, and excessive addition may even cause the texture to disappear.

(2) Mismatch of resin system:

Different manufacturers and models of resin have significant differences in melt flowability, which affects the performance of the wrinkle agent.

(3) Extrusion temperature is too high:

CAB-type wrinkle agents melt at 130–160℃. If the extrusion temperature exceeds 120℃, it may cause texture changes or disappearance.

(4) Interference from additives such as leveling agents and wax powders:

This may result in no texture formation or cause shrinkage defects.

(5) Aging of floating pattern agent:

After long-term storage, floating pattern agents (wrinkle agents) may become ineffective, resulting in failure to form wrinkles.

Solutions:

(1) Precisely control the amount of wrinkle agent according to the target texture size. Conduct small-scale trials first to determine the optimal amount before mass production.

(2) Select suitable wrinkle agent varieties according to resin characteristics. Different resin systems require matching additives.

(3) Strictly control the extrusion temperature below 120℃ to prevent premature melting and failure of the wrinkle agent.

(4) Avoid excessive addition of interfering additives such as leveling agents and wax powders.

(5) Powder coatings with externally added floating pattern agents should not be stored for too long and should be used as soon as possible.

4. Texture Instability Between Different Batches

Phenomenon:

The texture effect varies significantly between different production batches using the same formulation.

Causes:

(1) The wrinkle agent is not evenly dispersed in the powder coating, resulting in texture fluctuations between batches.

(2) The charging properties, specific gravity, and particle size of the base powder and externally added wrinkle agent are inconsistent. When spraying conditions change, the texture effect changes significantly.

Solutions:

(1) Before use, mix and disperse the wrinkle agent with fillers first, then add it into the powder coating to improve dispersion uniformity.

(2) Optimize the particle size matching between the base powder and wrinkle agent, ensuring that their charging properties and specific gravity are basically consistent, thereby improving spraying stability.

If you encounter some difficult problems during the use of wrinkle powder coating, please feel free to contact us at any time to obtain professional technical support. We are willing to discuss solutions together, promote the development of the powder coating industry, and advance the progress of the industry.

We hope this article can provide you with a professional and reliable reference regarding the powder coating industry. We sincerely welcome you to consult with us regarding powder coating product performance, industry standards, application methods, precautions, or any related questions. We look forward to your messages or direct contact at any time, so that we can provide you with more detailed product information, demonstration videos, or customized solutions, helping you fully understand all product functions and advantages.