This article systematically introduces the concept, formation principles, characteristics, functions, applications, selection considerations, and common problem-solving methods of wrinkle powder coating. It focuses on the application fields of wrinkle powder coating to help everyone better understand what wrinkle powder coating is, as well as its characteristics and functions.
What Is Wrinkle Powder Coating
Wrinkle powder coating is an environmentally friendly artistic powder coating that can form unique three-dimensional texture effects such as wrinkle patterns, soft ripple patterns, and mesh patterns.By changing the formulation of resins, curing agents, pigments, and additives (such as texture agents and catalysts), it utilizes the incompatibility or differences in reaction rates between different components during the curing process to promote uneven shrinkage of the coating surface during melt leveling, ultimately forming textured patterns with a three-dimensional concave-convex effect.
Types of Wrinkle Powder Coating
Classified by Texture Form1. Soft Ripple Texture
The texture is delicate and uniform, with a smooth and soft touch. Visually, it presents a continuous fine wrinkle effect similar to fabric texture. The gloss level is generally between 40% and 60%. It is suitable for applications requiring high touch quality and refinement, such as home appliance panels, office furniture, and electronic product housings.
2. Fine Mesh Texture
The texture presents a fine mesh structure with strong three-dimensional effects, obvious concave-convex appearance, and clear tactile feeling. The gloss level is usually within the range of 30% to 50%. It is suitable for applications such as security doors, lighting fixtures, and display racks that require certain visual impact and defect-covering ability.
3. Coarse Mesh Texture (Hammer Texture)
The texture is rough, with larger mesh patterns and strong three-dimensional effects, presenting a surface appearance similar to hammered metal. The gloss level is relatively low, generally around 30%. It is suitable for outdoor building materials, mechanical housings, agricultural equipment, and other workpieces requiring high covering ability and suitable for relatively rough substrate surfaces.
4. Sand Texture
The texture appears like fine sand particles, with uniformly distributed micro-particle effects on the surface, providing anti-slip and wear-resistant properties. The gloss level is usually below 30%, close to matte. It is suitable for tool handles, transportation facilities, elevator steps, and other applications requiring anti-slip surfaces.
5. Composite Type of Soft Ripple and Mesh Texture
A mesh texture effect is added on the basis of soft ripple texture, creating richer texture layers with both delicate touch and three-dimensional visual effects. It is suitable for high-end decorative building materials, customized furniture, and other fields pursuing unique appearances.
Wrinkle Formation Principle of Wrinkle Powder Coating
The basic principle of wrinkle powder coating is to utilize the uneven distribution of surface tension during the melting and curing process of the coating to induce directional shrinkage and surface undulation, ultimately forming three-dimensional textures. It can be achieved through the following three mechanisms:1. Phase Separation of Incompatible Systems
By introducing polymer components incompatible with the main resin system into the formulation, microscopic phase separation occurs during melting, forming resin-rich areas and resin-poor areas. The difference in surface tension between the two areas causes uneven shrinkage of the coating film, which is fixed as wrinkle patterns after cooling.
2. Reaction Rate Difference-Induced Shrinkage
Through selective control of catalysts or curing agents, differences in crosslinking reaction rates occur in different areas of the coating. Areas with faster reactions cure and shrink first, while slower-reacting areas continue to flow and fill. The time difference between the two causes uneven surface shrinkage, forming soft ripple or mesh texture effects.
3. Surface Tension Gradient Driven Effect
During melt leveling, temperature differences or reaction heat differences between the coating surface and interior create surface tension gradients, driving convection movement of molten polymers. This causes regular undulating deformation on the coating surface, which is locked into three-dimensional textures after curing.
Characteristics of Wrinkle Powder Coating
The main characteristics of wrinkle powder coating are as follows.1. Unique Three-Dimensional Decorative Effect
The coating surface presents regular concave-convex textures (such as soft ripple texture, mesh texture, and sand texture), with elegant matte gloss (usually a 60° gloss meter measurement value between 30% and 70%). It provides rich visual layers and delicate touch, giving products a high-end appearance. The texture can be adjusted by controlling formulation and processing parameters to achieve different texture sizes and depths.
2. Excellent Defect Covering Ability
The concave-convex texture can effectively cover minor defects on substrate surfaces, such as scratches, pinholes, welding marks, casting burrs, and rough surfaces of hot-rolled steel plates. This characteristic makes its substrate pretreatment requirements lower than high gloss powder coating, especially suitable for workpieces with lower surface flatness requirements, significantly reducing pretreatment costs.
3. Excellent Physical and Chemical Protection Performance
After curing, the coating is dense and tough, with good adhesion, impact resistance, and flexibility. At the same time, it has excellent resistance to acids, alkalis, salt spray, and weathering (especially outdoor types), effectively protecting substrates from corrosion and aging. Outdoor pure polyester systems show outstanding UV resistance and are suitable for metal components exposed outdoors for long periods.
4. Wide Application Tolerance and Environmental Advantages
Compared with high gloss powder coating, wrinkle powder coating has relatively lower requirements for spraying environment cleanliness, curing temperature fluctuations, and coating thickness uniformity. It is less likely to produce defects such as shrinkage holes and orange peel, providing better operational convenience. It also has the common environmental advantages of powder coatings—nearly zero VOC, recyclable overspray powder, and high comprehensive utilization efficiency.
Functions of Wrinkle Powder Coating
The main functions of wrinkle powder coating are reflected in the following aspects.1. High Decorative Function
It provides metal surfaces with unique three-dimensional texture effects, such as soft ripple texture, mesh texture, and sand texture. It offers rich visual layers, delicate touch, and elegant matte appearance. By adjusting formulation and processing technology, various texture styles from fine to rough can be achieved, significantly improving product appearance quality and artistic added value. It is widely used in security doors, furniture, lighting fixtures, decorative building materials, and other fields requiring special appearances.
2. Strong Defect Covering Function
The concave-convex texture can effectively cover minor defects on substrate surfaces, including scratches, pinholes, welding marks, casting burrs, and rough surfaces of hot-rolled steel plates. This feature allows wrinkle powder coating to have much lower substrate pretreatment requirements than high gloss powder coating, making it especially suitable for workpieces with poor surface flatness and helping enterprises significantly reduce pretreatment costs and rework rates.
3. Strong Physical and Chemical Protection Function
The dense coating formed after curing provides excellent adhesion, impact resistance, and flexibility. It also offers resistance to acids, alkalis, and salt spray corrosion. Outdoor pure polyester systems additionally provide excellent UV aging resistance. It effectively protects metal substrates from environmental erosion and mechanical damage, extends product service life, and is suitable for outdoor building materials, automotive parts, transportation facilities, and other applications requiring long-term exposure.
Application Fields of Wrinkle Powder Coating
Wrinkle powder coating is mainly applied in the following fields:1. Construction and Building Materials Field
It is applied to aluminum alloy doors and windows, security doors, fire doors, guardrails, curtain wall profiles, outdoor decorative panels, and other products. Wrinkle textures provide building materials with elegant and solid visual qualities. At the same time, outdoor pure polyester systems offer excellent weather resistance and UV aging resistance, maintaining appearance and protective performance for a long time. In addition, the concave-convex texture can effectively cover extrusion marks or welding marks on profiles, reducing pretreatment costs.
2. Home Appliance and Electronic Product Field
It is used for air conditioner panels, refrigerator side panels, washing machine top covers, microwave oven housings, audio equipment, chassis cabinets, and other products. Delicate soft ripple textures or sand textures can improve product appearance quality and tactile experience. Meanwhile, the coating provides excellent scratch resistance, stain resistance, and easy-cleaning properties, making it suitable for frequently used household appliances and electronic equipment.
3. Furniture and Interior Decoration Field
It is applied to office furniture (filing cabinets, desk and chair frames), display racks, lighting fixtures, indoor hardware components, decorative strips, and other products. Wrinkle textures not only provide rich decorative styles (from fine sand texture to coarse mesh texture), but also effectively cover minor scratches generated during processing, reducing surface treatment difficulty. At the same time, the coating is wear-resistant and scratch-resistant, making it suitable for long-term use.
4. General Industrial and Transportation Field
It covers automotive parts (engine covers, wheels, bumpers), bicycle frames, power tool housings, agricultural machinery, traffic barriers, electrical equipment housings, and other products. In these fields, wrinkle powder coating provides both corrosion resistance, impact resistance, and chemical resistance protection, as well as economic advantages by reducing surface treatment costs. It is especially suitable for castings or rough workpieces with lower surface flatness requirements.
How to Select Wrinkle Powder Coating
When selecting wrinkle powder coating, we may encounter difficulties in choosing the right product. Based on our industry experience, we recommend focusing on the following aspects.1. Consider Application Environment
First, determine the working environment of the workpiece.
(1) Indoor applications (furniture, electrical appliances, indoor hardware): Prefer epoxy or epoxy-polyester hybrid types, which offer lower cost, good adhesion, and excellent decorative performance;
(2) Outdoor applications (security doors, building curtain walls, automotive parts, transportation facilities): Pure polyester type must be selected, combined with weather-resistant pigments to ensure long-term UV resistance, gloss retention, and color retention, avoiding coating powdering and fading.
2. Consider Texture Effects
Select suitable texture styles according to design requirements.
Wrinkle textures can be divided into soft ripple texture (delicate and uniform with smooth touch), mesh texture (rough three-dimensional effect with strong covering ability), sand texture (fine sand appearance with anti-slip and wear resistance), and other types.
The size and depth of textures can be controlled by adjusting the type and amount of texture agents and catalysts in the formulation. Curing temperature and time also affect the final texture appearance. It is recommended to request standard samples with different textures from suppliers for comparison and selection.
3. Consider Performance Indicators
Determine key performance parameters according to workpiece requirements.
(1) Mechanical properties: Focus on impact strength (generally ≥40kg·cm), flexibility (≤2mm), and adhesion (cross-cut test ≤ Grade 1);
(2) Weather resistance: Outdoor applications should pass QUV accelerated aging tests (such as gloss retention ≥80% after 1000 hours);
(3) Chemical resistance: Additional corrosion resistance verification is required when exposed to oil stains, cleaning agents, or acid/alkali environments;
(4) Different fields also have gloss requirements. Wrinkle powder coating is generally matte (30%–70% gloss at 60°), and confirmation should be made according to design requirements.
4. Consider Application Compatibility
Evaluate whether production line conditions are suitable. For curing conditions, confirm whether the existing oven temperature (such as 200℃/10min or 180℃/15min) meets the curing window of the selected powder. For pretreatment capability, although wrinkle powder coating has high tolerance to substrate flatness, basic oil and rust removal capabilities (phosphating or silane treatment) are still required. For spraying equipment, ensure stable powder output from spray guns and adjustable electrostatic voltage (generally 60–90kV). For recycling, confirm that the recovery system is complete so overspray powder can be recycled and reused to reduce costs.
5. Consider Environmental Protection and Cost
Wrinkle powder coating itself has nearly zero VOC, but heavy metal content must be confirmed to comply with environmental regulations such as RoHS, especially for export products.
For cost considerations, comprehensively evaluate the price per kilogram, coating area utilization rate (powder deposition rate and recovery rate), cost savings from simplified pretreatment (due to excellent defect covering ability), and rework rate (strong texture covering ability can reduce defective product rates).
Common Problems and Solutions of Wrinkle Powder Coating
The most common problems during the use of wrinkle 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.1. Texture Too Fine or Too Coarse
Problem Description:
The texture size does not match the sample or design requirements. The pattern is too fine and loses its three-dimensional effect, or too coarse and appears rough.
Main Causes:
(1) Improper amount of texture agent (excessive amount results in fine texture, insufficient amount results in coarse texture);
(2) Curing temperature too high or too low (high temperature produces finer texture, low temperature produces coarser texture);
(3) Uneven coating thickness (thin areas produce fine texture, thick areas produce coarse texture);
(4) The type and amount of catalyst or defoamer do not match the resin system.
Solutions:
(1) Precisely control the amount of texture agent added (usually 0.1%–0.5% of total resin amount), and determine the optimal ratio through small-scale testing;
(2) Control curing temperature within the powder technical specification range (generally 180–200℃), maintain temperature difference within ±5℃ in the constant temperature zone, and control coating thickness at 60–80μm to ensure uniform powder deposition;
(3) Select catalysts and defoamers compatible with the resin system and fix raw material suppliers between batches.
2. Uneven Texture Problem
Problem Description:
Texture size and depth vary in different areas of the same workpiece, or texture fluctuations occur between workpieces in the same batch.
Main Causes:
(1) Uneven oven temperature distribution causes differences in local curing speed;
(2) Workpieces are hung too densely or complex shapes cause poor hot air circulation;
(3) Electrostatic shielding during spraying causes local coating thickness differences; uneven powder mixing and poor texture agent dispersion.
Solutions:
(1) Regularly test the nine-point temperature field of the oven to ensure temperature differences at each point ≤±5℃;
(2) Adjust hanging spacing >10cm to ensure hot air circulation;
(3) Adjust spray gun angles or add manual touch-up spraying for complex cavities or recessed areas;
(4) Extend powder premixing time to ensure uniform texture agent dispersion, while controlling recycled powder mixing ratio ≤30% and ensuring sieving.
3. Gloss Too High or Too Low
Problem Description:
The matte effect is out of control, and gloss exceeds the design range (target generally 30%–70%).
Main Causes:
(1) Curing temperature or time deviation affects gloss performance during texture formation;
(2) Improper ratio of matting agents, fillers, or pigments in the formulation;
(3) Moisture absorption of powder affects leveling and texture formation; different batches of raw materials (especially resin and catalysts) contribute differently to gloss.
Solutions:
(1) Strictly control curing temperature and time according to process requirements;
(2) Adjust the type and amount of matting agents and fillers in the formulation;
(3) Maintain powder storage conditions below 25℃ and RH <60%;
(4) Require suppliers to provide gloss inspection reports for each batch and fix raw material batches.
4. Particle or Dirt Spot Problems
Problem Description:
Raised particles appear on the coating surface, affecting texture appearance.
Main Causes:
Insufficient cleanliness of spraying environment (dust contamination); foreign materials mixed into powder or recycled powder not sieved; unmelted particles caused by poor extrusion process.
Solutions:
(1) Purify the spraying room environment, with a recommended cleanliness level of 10.000;
(2) Sieve powder through a 120-mesh screen before use, and also sieve recycled powder before mixing with new powder;
(3) Control extruder temperature to prevent local overheating and formation of gel particles, and regularly clean equipment.
5. Frosting or Whitening Problem
Problem Description:
The coating surface turns white, gloss decreases, and texture becomes unclear.
Main Causes:
(1) Insufficient curing causes incomplete surface crosslinking;
(2) Moisture absorption of powder causes resin hydrolysis;
(3) Mixing powders from different systems causes incompatibility.
Solutions:
(1) Increase curing temperature or extend holding time within the specified range;
(2) Store under moisture-proof conditions and confirm powder shelf life;
(3) Strictly prohibit mixing powders from different brands or different systems, and thoroughly clean the powder supply system when changing powders.
If you encounter difficult problems during the use of wrinkle powder coating, please feel free to contact us at any time to obtain professional technical support, jointly discuss solutions, and promote the development of the powder coating 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 us regarding product performance, industry standards, usage methods, precautions, or any related questions about powder coating products. We look forward to receiving your inquiries through messages or direct contact at any time, so that we can provide you with more detailed product information, demonstration videos, or customized solutions to help you fully understand the various functions and advantages of our products.
