News

Knowledge

Company News

Application Mind Map

Test Report

Technical Article

Industry News

Process flow of UV 3C coatings

Release time:

2026-06-17 23:21

The performance advantages of UV 3C coatings stem not only from their formulation but are also closely tied to the coating application process. From substrate pretreatment to coating application, and from solvent evaporation to UV curing, the precise control of parameters at each stage directly influences the coating’s adhesion, surface appearance, and durability. Compared with other coating processes, UV 3C coatings demand particular attention to energy matching during curing and to protecting heat‑sensitive substrates. A thorough understanding of the entire process flow and the key control points at each step is essential for grasping how UV 3C coatings deliver effective, consistent coating results on the production line.

I. Substrate Pre-treatment

Substrate pretreatment is the initial step in UV 3C coating and directly affects coating adhesion. The housings of 3C products typically use plastic substrates such as ABS, PC, or PC/ABS, whose surfaces may harbor contaminants like release agents, oils, and dust. The primary objective of pretreatment is to remove these contaminants through solvent cleaning, ensuring that the substrate surface is thoroughly clean.

Electrostatic dust removal is a critical step in the pretreatment process. During handling, plastic substrates are prone to generating static electricity, which can attract fine particulates from the air. Employing an ionizing air gun or an electrostatic dust‑removal system neutralizes surface charges and eliminates adsorbed dust, thereby preventing particle‑related defects from becoming trapped within the coating.

II. Primer Spraying

The primer serves as the foundational layer in a UV 3C coating system, sealing substrate defects and ensuring adhesion. Primer application is typically carried out in a cleanroom, using automated spraying to maintain uniform coating thickness. For workpieces with complex geometries, multiple spray guns are often deployed from different angles to ensure that all surfaces of the intricate parts receive even paint coverage.

After primer application, infrared leveling or low‑temperature baking is required. The purpose of this step is to allow the solvents in the coating to fully evaporate before curing, while ensuring the coating spreads evenly across the substrate surface and eliminates spray marks. The baking temperature should not be too high to protect heat‑sensitive plastic substrates and prevent deformation caused by excessive heat.

III. UV Topcoat Spraying and Curing

The topcoat is the outer layer of the UV 3C coating system, providing key functions such as wear resistance, scratch resistance, and decorative appeal. Topcoat application is carried out after the primer has cooled, with automated spraying employed to ensure uniform coating thickness.

After topcoat application, a pre‑heating and leveling step is typically required to ensure the coating fully spreads before UV irradiation, thereby eliminating spray marks. The adequacy of leveling directly affects the surface smoothness and the uniformity of gloss after curing.

UV curing is a core step in the UV‑3C coating process. After leveling, the workpiece enters the UV curing unit, where, under ultraviolet irradiation, the photoinitiators in the coating decompose to generate free radicals, initiating a polymerization reaction that cures the coating within seconds. The curing energy must be precisely controlled: insufficient energy results in incomplete curing and a tacky surface, while excessive energy may cause yellowing of the coating or thermal damage to the substrate.

IV. Process Expansion

As consumer electronics increasingly demand superior surface textures, the excimer‑induced skin‑like finish process has been adopted in UV 3C coating. This process employs ultraviolet light of a specific wavelength to irradiate the coating, causing an ultra‑thin surface layer to contract and develop a non‑smooth micro‑topography, thereby achieving a refined, skin‑like tactile effect.

The application process for excimer skin‑feel coatings comprises the following steps: workpiece inspection, surface preparation, primer spraying, infrared baking, excimer topcoat spraying, infrared leveling, pre‑curing, excimer curing, conventional curing, and final inspection and packaging. Notably, the excimer curing stage must be carried out under specific conditions to develop the desired skin‑feel surface texture, while subsequent conventional curing ensures complete crosslinking of the entire coating system.

V. Quality Inspection

Quality inspection after coating is completed is a critical step in ensuring product compliance. Inspection items include color and gloss, abrasion resistance, and adhesion. Abrasion resistance is tested using a dedicated testing instrument, while adhesion is assessed by applying a grid‑cutting tool to the coated surface, then peeling off adhesive tape to evaluate coating delamination.

VI. Conclusion

The process flow for UV 3C coatings encompasses key stages such as substrate pretreatment, primer application and baking, UV topcoat application and curing, and quality inspection. Substrate pretreatment ensures a clean surface, laying the foundation for adhesion; the primer provides adhesion and sealing; the UV topcoat delivers wear resistance, scratch resistance, and decorative effects; while advanced technologies like excimer‑based tactile finishes further expand the diversity of surface aesthetics. Precise control of process parameters at each stage is essential to ensure coating uniformity and reliability.

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 fullness, 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	Good leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon photocurable resin	Good 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	Good flexibility, excellent 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-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	Good leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon photocurable resin	Good 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 fullness, 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.

Share to:

Key Process Points for UV 3C Coatings

Application Requirements for UV 3C Coatings