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How to Address Defects in UV 3C Coatings (Part II)

Release time:

2026-06-30 23:43

How to Address Defects in UV 3C Coatings (Part II)

In the actual production of UV 3C coatings, particulates and impurities are among the most common defects that affect surface quality. They manifest as tiny, raised particles on the coating film, which feel rough to the touch and appear as distinct point-like defects under illumination. To address this issue, appropriate measures must be implemented across several stages, including control of the application environment, thorough cleaning of the workpiece surface, proper coating management, and regular equipment maintenance. This paper outlines methods for mitigating particulate and impurity-related defects, focusing on environmental purification, surface preparation, coating filtration, and equipment cleaning.

I. Purification of the Construction Environment

Dust in the construction environment is the primary source of particulate defects. Mitigation requires addressing both air filtration and environmental cleanliness. The spray booth’s air filtration system should be regularly inspected and its filters replaced to ensure that incoming air is effectively filtered. Positive pressure within the booth must be maintained consistently to prevent unfiltered ambient air from entering.

The walls, floors, and ceilings of the spray booth should be cleaned regularly to minimize dust accumulation. Wet cleaning is preferred; dry sweeping should be avoided to prevent re‑suspension of dust. Unnecessary items should be kept out of the spray booth to maintain a tidy work area. Operators must wear cleanroom garments and caps while inside the booth to reduce the introduction of human‑borne particulates into the work zone.

II. Removal of Contaminants from the Workpiece Surface

Release agents, oil contaminants, and dust on the workpiece surface are significant sources of particulate defects. Prior to coating, the workpiece must be thoroughly cleaned. The cleaning method should be selected based on the material of the workpiece and the extent of contamination, and may include solvent wiping, ultrasonic cleaning, or spray washing, among others.

Mold release agent residues are particularly stubborn and require treatment with a dedicated mold‑release‑agent cleaner. After cleaning, rinse thoroughly with deionized water to remove any residual cleaner. Oil contaminants can be removed using an alkaline cleaner or a solvent‑based cleaner; ensure that the workpiece surface is completely dry following cleaning. For parts with complex geometries, make sure the cleaning solution reaches all areas during rinsing to prevent localized residue.

Workpieces after cleaning should be protected from recontamination during storage and handling. Operators must wear clean gloves to prevent direct contact between bare hands and the workpiece surfaces. Cleaned workpieces should be coated within the specified time frame to avoid prolonged exposure to the environment, which could lead to dust adsorption.

III. Filtration Management of Coatings

Impurities and skin formation in coatings are among the sources of particulate defects. Prior to application, the coating must be thoroughly filtered. The mesh size of the filter should be selected based on the desired fineness of the coating and the specified particle‑size control criteria, ensuring that any potential impurity particles are effectively removed.

Filtering operations should be performed in accordance with established procedures to ensure that all paint passes through the filter, preventing any overflow at the filter edges. Filter screens should be inspected regularly, and any damaged screens must be replaced promptly. For paint that has already been opened, the container should be tightly sealed after use to prevent dust from entering. When transferring paint between containers, care should be taken to avoid allowing dried paint residue from the container rims to fall into the fresh paint.

IV. Cleaning of Spraying Equipment and Auxiliary Tools

Equipment-related factors, such as spray guns, piping, and fixtures, are among the sources of particulates. During operation, spray equipment should be cleaned and maintained on a regular schedule. Residual dried paint in the spray gun nozzle, air cap, and coating lines must be removed periodically to prevent flaking and particle formation during spraying.

The compressed air system shall be equipped with oil–water separators and precision filters, with regular drainage of accumulated condensate to ensure that the compressed air remains clean and dry. Filter elements must be replaced on schedule to maintain optimal filtration performance.

Dried paint residues adhering to the surfaces of hangers and workpiece racks should be cleaned regularly. These can be removed by mechanical sanding or by soaking in a dedicated cleaning agent. The contact points between the hangers and the workpieces should be kept smooth to minimize debris generated by friction.

V. Integrated Process Control

Addressing particle defects requires comprehensive control across multiple stages. In terms of the environment, maintain cleanroom conditions and positive pressure; for the workpieces, ensure that surfaces are clean and free of contaminants prior to coating; with respect to coatings, standardize filtration procedures and implement airtight storage; and for equipment, perform regular cleaning of spray‑coating systems and compressed‑air networks.

Control at each stage is interrelated, and any oversight in a single step can introduce particulate defects. In actual production, the primary sources of such defects can be identified by analyzing their spatial distribution and morphological characteristics, enabling targeted reinforcement of control measures at the corresponding stages.

VI. Conclusion

The management of particulate and impurity defects involves multiple stages, including the spray booth environment, workpiece surface condition, coating handling, and equipment cleaning. By enhancing air filtration and environmental hygiene in the spray booth, ensuring that workpieces are clean and free from contamination, standardizing coating filtration and storage, and performing regular maintenance on spraying equipment and compressed‑air systems, the occurrence of particulate defects can be effectively minimized. Successful control at each stage requires coordinated efforts, with careful consideration of environmental conditions, equipment status, and operational procedures, to achieve optimal results.

Disclaimer: The above content has been compiled from publicly available sources and is provided for reference only. If any infringement occurs, please contact us, and we will address it promptly.

Bossin Related Product Recommendations – 3C Coatings
General-purpose
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-102	Bisphenol A epoxy acrylate	High hardness, high gloss, chemical resistance, contains 15% TMPTA.
B-151	Modified epoxy acrylate	Low halogen, yellowing-resistant, excellent plating performance, and strong adhesion.
B-165	Modified epoxy acrylate	Good flexibility and strong adhesion
B-216	Aliphatic polyurethane acrylate	Fast curing, high build, and excellent toughness.
B-368	Aliphatic polyurethane acrylate	Good toughness, excellent leveling, excellent bend resistance, and excellent heat resistance.
B-574C	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV.
B-601	Aromatic polyurethane acrylate	High hardness, scratch resistance, chemical resistance, and excellent cost-effectiveness.
B-6019	Special functional group acrylate	Good leveling, excellent wettability, resistant to boiling water, and superior color dispersion.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
B-615A	Aliphatic polyurethane acrylate	Fast curing, excellent toughness, wear resistance, and chemical resistance.
B-619W	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, wear resistance, and chemical resistance.
B-6380N	Special functional group acrylate	Excellent adhesion to plastics, strong hiding power, and improved paint film appearance.
B-919B	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, and outstanding chemical and wear resistance.
Matte
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-572	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV.
B-650A	Aliphatic polyurethane acrylate	Low viscosity, excellent matting effect, fast curing, and good wettability.
Wearable device
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-6211	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch-resistant, and free of organotin.
Hand feel
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, excellent wettability, and a pleasant hand feel.
B-868	Organosilicon photocurable resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon photocurable resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
Large-area spraying
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-374	Aliphatic polyurethane acrylate	Excellent flexibility, good leveling, resistant to abrasion and chemicals, and resistant to yellowing.
Car interior
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-6063	Special functional group acrylate	High molecular weight, low curing shrinkage
B-6210	Aliphatic polyurethane acrylate	Low viscosity, chemical resistance, environmental resistance, and dual photothermal curing.
B-6263	Special functional group acrylate	Fast curing, high build, boil‑water resistant, and excellent toughness.
B-916	Aliphatic polyurethane acrylate	Low viscosity, solvent resistance, chemical resistance, and steel-wool resistance.
B-919B	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, and outstanding chemical and wear resistance.
Resistant to steel wool
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-910A2	Aliphatic polyurethane acrylate	Low viscosity, yellowing resistance, chemical resistance, and steel-wool resistance.
B-916	Aliphatic polyurethane acrylate	Low viscosity, solvent resistance, chemical resistance, and steel-wool resistance.
B-919B	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, and outstanding chemical and wear resistance.
Oil-resistant pen
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-868	Organosilicon photocurable resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon photocurable resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
Battery casing
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-431	Cycloaliphatic Specialty Acrylate	Yellowing-resistant, excellent wettability, low viscosity, fast curing
B-548	Polyester acrylate	Withstands high temperatures of 250–280°C.
Solid color paint
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-519	Self-curing polyester acrylate	Self-initiated photopolymerization performance
B-560	Polyester acrylate	Fast curing and excellent pigment wetting.
Yellowing resistance
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-151	Modified epoxy acrylate	Low halogen, yellowing-resistant, excellent plating performance, and strong adhesion.
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and excellent adhesion.
B-216	Aliphatic polyurethane acrylate	Fast curing, high build, and excellent toughness.
B-296	Aliphatic polyurethane acrylate	Fast curing, chemical resistance, yellowing resistance, impact resistance
B-431	Cycloaliphatic Specialty Acrylate	Yellowing-resistant, excellent wettability, low viscosity, fast curing
Monomer Recommendation
Product Model/English Abbreviation	Product Name/Product Type	Product Features
BM3231 (TMPTA)	Trimethylolpropane triacrylate	High crosslink density, high hardness, high gloss, and excellent wear resistance.
BM3235 (PET3A)	Pentaerythritol triacrylate	Fast curing, high crosslink density, high hardness, and chemical resistance.
BM3380 (3EO-TMPTA)	Pentaerythritol triacrylate	More flexible and less irritating than TMPTA.
BM4241 (DiTMPTA-80)	Bis(2,3-dihydroxypropyl) tetraacrylate	High crosslink density, high hardness, chemical and wear resistance, and water resistance.
BM4242 (Di-TMPTA)	Bis-trimethylolpropane tetraacrylate	High crosslink density, high hardness, chemical and wear resistance, and water resistance.
BM6261 (DPHA-80)	Dipentaerythritol hexaacrylate	High crosslink density, high hardness, chemical and wear resistance, and water resistance.
BM6263 (DPHA-90)	Dipentaerythritol hexaacrylate	High crosslink density, high hardness, chemical and wear resistance, and water resistance.

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How to Address Defects in UV 3C Coatings (Part 3)

How to Address Defects in UV 3C Coatings (Part 1)