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Core Components of UV Inkjet Ink

Release time:

2026-02-26 07:18

In the field of digital printing, UV inkjet inks have emerged as a key driver of industry growth, thanks to their exceptional print quality and broad applicability. Underpinning this performance is a carefully selected and precisely formulated blend of raw materials that work in concert to deliver outstanding ink characteristics.

I. Prepolymer

Prepolymers, also known as oligomers or dimers, are the primary constituents of the ink film formed upon curing; they typically serve as polymer precursors containing polymerizable functional groups, such as acrylate groups. The molecular structure of prepolymers directly influences the mechanical strength, flexibility, adhesion, and chemical resistance of the cured film. Common types include epoxy acrylates, polyurethane acrylates, and polyester acrylates, which can be selected based on the specific requirements of the end application regarding hardness, scratch resistance, and weatherability.

II. Reactive Diluents

Reactive diluents, also known as reactive monomers, serve a dual purpose: they adjust the viscosity of the formulation to meet the spray requirements of the applicator, and they participate in polymerization and crosslinking during the photopolymerization process, thereby influencing the crosslink density and ultimate performance of the ink film.

Based on functionality, monomers can be classified as mono-functional, di-functional, or poly-functional. Poly-functional monomers help enhance cure speed and hardness, while mono-functional monomers are conducive to improving flexibility and adhesion.

III. Photoinitiators

Photoinitiators are key components of UV-curing systems; upon absorbing ultraviolet light, they generate reactive free radicals or cations, which in turn initiate the polymerization of prepolymers and monomers. Based on their mechanisms of action, they can be classified as:

1. Photocleavage type: Upon exposure to light, the molecule undergoes intramolecular cleavage to generate free radicals, resulting in rapid curing;

2. Hydrogen-abstraction type: Requires synergistic action with a co-initiator to generate free radicals, suitable for thick-film or colored systems.

The selection of a photoinitiator must be matched to the emission wavelength of the UV light source used, while also considering its solubility in the system and its tendency to cause yellowing.

IV. Colorants

Colorants impart color and opacity to inks and primarily include:

1. Pigments: Dispersed in the system in the form of fine particles, they exhibit excellent lightfastness, weather resistance, and chemical stability, making them suitable for outdoor applications and other applications with high durability requirements.

2. Dyes: They are soluble in the system, offer vibrant colors and high transparency, but have only moderate weather resistance, making them suitable for indoor use or short-term applications.

The dispersion stability of pigments directly affects ink storage stability and print quality, often requiring the use of dispersants and milling processes to achieve uniform dispersion.

V. Functional Additives

There is a wide variety of additives; although used in small quantities, their role is critical:

1. Dispersant: Enhances the dispersion stability of pigments and prevents sedimentation and aggregation;

2. Leveling agent: Improves the uniformity of ink film spread and reduces cratering and orange-peel defects.

3. Defoamer: inhibits foam formation to prevent printing defects;

4. Adhesion promoter: enhances the adhesion of the ink film to various substrates;

5. Stabilizers: including UV absorbers and polymerization inhibitors, which enhance the storage and application stability of the ink.

VI. Summary

UV inkjet inks are composed of a multi-component system in which prepolymers form the ink film matrix, reactive diluents optimize processability, photoinitiators drive the curing reaction, colorants deliver the desired color appearance, and various additives further enhance storage stability, printability, and end-use performance. Through the rational formulation and precise control of these components, high-performance UV inkjet products can be developed for diverse substrates and applications, thereby supporting their widespread use in packaging printing, industrial marking, decorative finishing, and other fields.

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Bossin Related Product Recommendations – UV Inkjet
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-21	Active amine photosensitizing promoter	Low color number, benzene-free, antioxidant and polymerization inhibitor, and enhanced curing rate.
B-27	Active amine photosensitizing promoter	Low color number, benzene-free, low odor, antioxidant and anti-polymerization
B-270	Aliphatic polyurethane acrylate	Low viscosity, good flexibility, excellent wettability, and excellent leveling.
B-271	Aliphatic polyurethane acrylate	Flexibility, low shrinkage, weather resistance, and pigment wetting
B-39	Aliphatic polyurethane acrylate	Low viscosity, good flexibility, and low volatility.
B-570	Polyester acrylate	Low viscosity, benzene-free, low odor, suitable for LED UV
B-572	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV
B-574	Polyester acrylate	Benzene-free, low odor, and VOC levels meet cigarette pack standards.
B-574C	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
B-619W	Aliphatic polyurethane acrylate	Fast curing, high hardness, good toughness, wear resistance, and chemical resistance.
BM1211 (HPMA)	Hydroxypropyl methacrylate	HEMA-free, high strength, low irritation, high adhesion
BM2223 (TPGDA)	Di(propylene glycol) diacrylate	Good flexibility and low volatility
BM2224 (EO-HDDA)	Ethoxy-1,6-hexanediol diacrylate	Excellent adhesion to plastics, good dilutability, and low volatility.
BM3231 (TMPTA)	Trimethylolpropane triacrylate	High crosslink density, high hardness, high gloss, and excellent wear resistance.
BM3380 (3EO-TMPTA)	Ethoxylated trimethylolpropane triacrylate	More flexible and less irritating than TMPTA.
BM3384 (3PO-GPTA)	Propylene Oxide Glycerol Triacrylate	Good flexibility, low irritation, and excellent pigment wetting.

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The Diverse Value of Inkjet Ink

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