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How to Address Defects in UV 3C Coatings (Part 7)

Release time:

2026-07-02 17:05

How to Address Defects in UV 3C Coatings (Part 7)

In the actual production of UV 3C coatings, insufficient curing is one of the key defects that compromise coating performance. It manifests as a tacky surface, inadequate hardness, and poor adhesion after curing, directly undermining the coating’s protective function and the product’s reliability. Curing is the critical step that distinguishes UV coatings from conventional ones; insufficient curing indicates that the crosslinking reaction has not proceeded to completion. To address this issue, appropriate measures must be taken across multiple fronts, including maintenance of curing equipment, adjustment of process parameters, and careful selection of compatible coating formulations. This paper outlines strategies for mitigating insufficient curing by focusing on UV lamp management, optimization of irradiation time, stabilization of energy output, and ensuring proper coating compatibility.

I. Maintenance and Replacement of UV Lamp Tubes

Insufficient UV lamp power is the primary equipment-related cause of inadequate curing. During operation, the lamp’s output energy gradually declines; therefore, a system for monitoring lamp condition and scheduling regular replacements should be established. Use an energy meter to periodically measure the lamp’s output, compare the measured values with the process‑required specifications, and determine whether replacement is necessary. The testing frequency should be tailored to the lamp’s usage conditions: for new lamps, the interval can be extended, while lamps nearing the end of their service life should be inspected more frequently.

The quartz glass on the lamp tube’s surface may become coated with contaminants during operation, reducing the ultraviolet transmittance. Regularly cleaning the tube’s surface to remove accumulated dust and volatile residues can help restore some of its output efficiency. Cleaning the reflector is equally important; a dirty reflector lowers reflection efficiency, thereby diminishing the effective energy reaching the coating surface.

When replacing lamp tubes, ensure that the model matches; lamps with different power ratings and spectral outputs directly affect curing performance. After replacement, re‑measure the energy output to confirm it meets process specifications. Maintaining a stock of spare lamps helps prevent production downtime caused by unexpected lamp failure.

II. Adjustment of Irradiation Time

Insufficient irradiation time is a process-related factor that leads to inadequate curing. During processing, the conveyor belt speed must be adjusted according to the coating type and thickness. For thick coatings or those containing pigments, longer irradiation times are required, and the conveyor speed should be reduced accordingly. Dark‑colored systems exhibit strong absorption of UV light and limited penetration depth, necessitating a corresponding extension of the irradiation time.

Curing speeds vary among different coating products, so the curing time should be re-validated when switching coating formulations. Variations in coating thickness also affect the required curing time; as thickness increases, the irradiation time must be extended accordingly. Regularly measuring coating thickness to ensure it remains within the process control limits helps maintain consistent curing conditions.

III. Stabilization of Energy Output

Insufficient output energy from the lamp tube is often attributable to unstable supply voltage. To address this, a voltage regulator can be installed at the front end of the curing equipment to mitigate the impact of grid fluctuations on the lamp’s output power. Additionally, regularly inspect electrical connections and tighten any loose terminals to ensure reliable contact in the power supply circuit.

Dirt or oxidation on the reflector can reduce its reflectance, thereby decreasing the effective energy reaching the coating surface. Regularly clean the reflector’s surface using a dedicated cleaning agent and a soft cloth, taking care to avoid scratching the reflective surface. If the reflector becomes aged or deformed, it should be replaced promptly to maintain optimal reflectance.

IV. Compatibility Between Coatings and Curing Equipment

Different coating formulations have varying requirements for curing energy. During processing, curing parameters must be adjusted to suit the specific characteristics of the coating being used. When switching coating types, a small‑scale trial should be conducted first to determine the optimal curing energy and irradiation time before proceeding to full‑scale production.

The type and dosage of the photoinitiator influence the curing rate. For coatings with slower cure rates, consider optimizing the photoinitiator system or increasing the curing energy. The curing‑parameter recommendations provided by the coating supplier can serve as a starting point; however, the optimal process parameters should be determined through experimentation.

V. Integrated Process Control

Addressing insufficient curing requires a comprehensive, multi‑faceted approach that integrates equipment maintenance, process parameters, and coating compatibility. On the equipment side, this involves regularly monitoring lamp output, cleaning lamps and reflectors, and installing voltage‑stabilizing devices; on the process side, it entails adjusting irradiation time and conveyor speed based on coating thickness and color; and on the coating side, ensuring that curing parameters are properly matched to the coating’s characteristics.

The control of each process step is interrelated, and adjustments must be made with a holistic approach. In actual production, the primary cause of insufficient curing can be identified based on its characteristic symptoms: surface tackiness is typically associated with lamp aging or inadequate irradiation time, while deep‑layer undercuring may result from excessive coating thickness or poor penetration in dark‑colored systems.

VI. Conclusion

Addressing insufficient curing defects involves multiple steps, including UV lamp management, adjustment of irradiation time, stabilization of energy output, and proper matching of coatings. By conducting regular lamp inspections and replacements, tailoring irradiation times to the specific coating characteristics, installing voltage‑stabilizing devices and cleaning reflectors, and verifying compatibility between the coating and the curing equipment, the curing performance can be significantly improved. Optimizing each of these aspects requires coordinated efforts, with careful consideration of equipment condition, material properties, and process requirements, in order to achieve a high level of curing quality.

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.

Bosheng Related Product Recommendations – 3C Coatings
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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
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B-572	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV.
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B-6211	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch-resistant, and free of organotin.
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B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, excellent wettability, and a pleasant hand feel.
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B-6063	Special functional group acrylate	High molecular weight, low curing shrinkage
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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.
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B-910A2	Aliphatic polyurethane acrylate	Low viscosity, yellowing resistance, chemical resistance, and steel-wool resistance.
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B-919B	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, and outstanding chemical and wear resistance.
Oil-resistant pen
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B-868	Organosilicon photocurable resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
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B-548	Polyester acrylate	Withstands high temperatures of 250–280°C.
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B-151	Modified epoxy acrylate	Low halogen, yellowing-resistant, excellent plating performance, and strong adhesion.
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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
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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 8)

How to Address Defects in UV 3C Coatings (Part 6)