UV inkjet ink is a type of special ink that forms a cured film through ultraviolet light exposure. It is widely used in advertising graphics, packaging printing, and industrial flatbed applications. Compared with solvent-based ink, UV ink does not rely on solvent evaporation for drying, therefore offering specific advantages and industry requirements in terms of environmental performance and odor control. This article analyzes UV ink eco-friendliness, odor sources, evaluation methods, and related standards.
I. Environmental Performance Characteristics of UV Inkjet Ink
Low Volatile Organic Compounds (Low VOC)
UV ink cures mainly through photoinitiated polymerization rather than solvent evaporation.
Compared to traditional solvent-based inks, VOC emissions are significantly lower, helping improve the working environment.
High Solid Content
UV ink typically contains more than 90% solid content, resulting in high curing efficiency.
This reduces environmental pollution caused by solvent evaporation.
No Ozone or Smoke Generation
UV curing systems use LED or mercury lamps.
The printing process does not generate smoke, dust, or secondary pollutants.
Compatible with Environmental Certifications
Some UV inks can meet the following environmental certifications:
ROHS (Restriction of Hazardous Substances)
REACH (Chemical Compliance)
SGS Testing
EN71 (Toy Safety Non-Toxic Standard)
Compliance is mainly based on the safety selection of monomers and photoinitiators in the ink formulation.
II. Odor Sources and Influencing Factors of UV Inkjet Ink
Although UV ink has low VOC emissions, odor may still be present. The main sources include:
Active Monomers
Certain acrylate monomers have irritating odors.
Monomer volatility directly affects odor intensity.
Photoinitiators
Photoinitiators may produce residual odor when not fully cured.
Traditional systems such as TPO and BDTK often exhibit noticeable smell.
Incomplete Curing
Insufficient UV energy, thick ink layers, or overlapping colors may cause only surface curing while trapping residual monomers below.
Under such conditions, odor may continue to be released over time.
Substrate Absorption and Release
Some materials (e.g., PVC) have strong absorption capacity, extending the odor release period.
III. Odor Evaluation and Testing Methods for UV Ink
Common industry methods for evaluating odor include:
Sensory Assessment
Odor intensity is subjectively graded as odorless, slight, moderate, or strong.
VOC Testing (Volatile Organic Compounds)
Quantitative measurements are performed using gas chromatography–mass spectrometry (GC-MS).
TDI (Total Odor Intensity) Evaluation
Some countries quantify odor using odor intensity index systems.
Complete Curing Verification
Methods include wipe tests, needle penetration tests, or UV curing energy assessments.
IV. Standards Related to Environmental and Odor Requirements
International standards related to UV ink focus mainly on material safety and emission control, including:
EU REACH Regulation
Restricts high-risk chemical substances
Requires registration and component disclosure
ROHS Directive
Limits heavy metals such as lead, cadmium, and hexavalent chromium
Blue Angel (Germany)
Sets strict requirements for VOC emissions and odor performance
Toy EN71 Standard
Non-toxic requirements for toy-related applications
ISO 16000 Indoor Air Standards
Covers testing for VOC emissions and indoor environmental safety
Due to regulatory differences between countries, there is currently no unified global standard specifically for UV ink odor. However, the industry trend is moving toward reduced irritant monomers and low-odor photoinitiator formulations.
V. Technology Trends for Low-Odor and Eco-Friendly UV Ink
To meet environmental and workplace comfort requirements, UV ink formulations are evolving toward:
Low-Irritation Monomer Substitution
Reduces odor and skin sensitization
Low-Odor Photoinitiator Systems
Uses TPO-L, 819, or similar systems to replace traditional initiators
LED-UV Curing Technology
Improves curing efficiency, reduces heat impact, and decreases uncured residue
High Solid Content and Fast-Curing Formulations
Further reduce VOC exposure and odor generation
UV inkjet ink provides significant environmental advantages compared with solvent-based ink, including low VOC emission, high solid content, and compatibility with multiple eco certifications. However, odor issues remain closely related to monomer selection, photoinitiator chemistry, and curing conditions. The industry currently focuses on formulation optimization and curing technology improvements to reduce odor and enhance environmental compliance. With the adoption of LED curing and low-odor raw materials, the environmental performance of UV inkjet inks is expected to continue improving.