In the continuous development of the printing industry, ink, as a core consumable, directly affects printing quality, production efficiency, and environmental benefits. Traditional printing inks and UV printing inks coexist in the market, each with unique application scenarios and characteristics. For professionals, having a deep understanding of the differences between the two can help make more suitable choices in actual production.

I. Composition

Traditional Printing Inks: Mainly composed of pigments, vehicles, fillers, and additives. Pigments give the ink color, while vehicles carry the pigments and enable them to adhere to the substrate. Common vehicles include drying vegetable oils and mineral oils. Fillers are used to adjust certain physical properties of the ink, such as reducing costs and improving ink fluidity. Additives include drying agents, dispersants, plasticizers, etc., which improve the printability and drying properties of the ink. For example, in offset printing inks, commonly used drying agents are organic salts of metals such as cobalt and manganese, which accelerate the oxidative drying process of the ink.

UV Printing Inks: Composed of oligomers (resins), monomers, photoinitiators, pigments, and additives. Oligomers are the main components that form the film layer after ink curing, determining the basic properties of the ink such as hardness, flexibility, and wear resistance. Monomers participate in polymerization reactions under the action of photoinitiators, contributing to the formation of a cross-linked network, enhancing the curing speed and film layer properties of the ink. Photoinitiators are key components of UV inks, which rapidly decompose under UV radiation to generate radicals, initiating polymerization reactions. Additives are used to improve certain properties of the ink, such as leveling and defoaming.

II. Curing Principles

Traditional Printing Inks: Curing methods mainly include oxidative polymerization drying, evaporative drying, and penetration drying. Oxidative polymerization drying is based on the oxidation reaction between unsaturated double bonds in drying vegetable oils and oxygen in the air, forming large molecular polymers that dry the ink. This drying method is relatively slow, often requiring several hours or even longer for complete drying. Evaporative drying achieves drying by volatilizing solvents, leaving solid components of the ink on the substrate surface, commonly used in solvent-based inks. Penetration drying involves the liquid components of the ink penetrating into porous substrates such as paper, leaving solid components like pigments on the surface to dry, commonly seen in newspaper printing.

UV Printing Inks: Cured through UV radiation. When UV ink is exposed to UV radiation of a specific wavelength, the photoinitiator absorbs photon energy, exciting and generating radicals. These radicals quickly initiate polymerization reactions between monomers and oligomers, forming a three-dimensional cross-linked polymer network structure, instantly transforming the ink from liquid to solid. The entire curing process is typically completed within milliseconds to seconds, significantly improving production efficiency.

III. Printing Performance

Drying Speed: Traditional printing inks have a relatively slow drying speed, especially those dried by oxidative polymerization, which limits the operating speed of printing presses. In multicolor printing, it is necessary to wait for the previous color ink to dry before printing the next color, otherwise issues such as ink mixing and smudging may occur. In contrast, UV printing inks dry extremely quickly, almost instantly, allowing printing presses to operate at high speeds, greatly improving production efficiency, and enabling subsequent processing such as die-cutting and laminating immediately after printing.

Printing Accuracy: Due to their fast curing speed, UV printing inks exhibit minimal diffusion and penetration on the substrate, enabling finer pattern and text printing. In fields with extremely high printing accuracy requirements, such as label printing and circuit board printing, UV inks have significant advantages. During the drying process of traditional printing inks, slight diffusion of the ink may occur due to their slow drying speed, affecting the clarity of printed patterns and the sharpness of edges.

Ink Transferability: The transferability of traditional printing inks is greatly influenced by factors such as ink viscosity and fluidity. During the printing process, adjustments to ink viscosity may be necessary based on the characteristics of the printing equipment and substrate to ensure even transfer of the ink onto the printing plate and substrate. UV printing inks are typically designed with good rheological properties, enabling stable transfer under different printing conditions and strong adaptability to printing equipment.

IV. Environmental Characteristics

Traditional Printing Inks: Solvent-based traditional inks contain a large amount of volatile organic compounds (VOCs), which volatilize into the air during printing, causing environmental pollution and posing health hazards to operators. Even water-based inks, which reduce VOC emissions to some extent, may still contain certain additives and residual organic solvents. Additionally, the drying process of traditional inks usually requires significant energy consumption, such as through heating to accelerate drying.

UV Printing Inks: Almost free of VOCs, they do not emit harmful gases into the air during printing, complying with environmental requirements. Simultaneously, due to their fast curing speed, they do not require a long drying process, significantly reducing energy consumption. This gives UV printing inks clear advantages in environmental protection and sustainable development, increasingly favored by the market.

V. Cost Factors

Ink Cost: The raw material cost of UV printing inks is relatively high, especially for photoinitiators and some high-performance oligomers, resulting in higher ink prices compared to traditional printing inks. However, with the continuous development of UV technology and increasing market demand, the cost of UV inks is gradually decreasing.

Equipment Cost: Using UV printing inks requires specialized UV curing equipment, such as UV lamps, reflectors, cooling systems, etc., increasing the purchase and maintenance costs of printing equipment. In contrast, traditional printing inks have relatively lower equipment requirements, with general printing presses meeting usage needs.

Overall Cost: Although the initial investment in UV printing inks and equipment is higher, their fast drying speed and high production efficiency can reduce labor costs and space occupancy costs. Meanwhile, the low waste rate and environmental advantages of UV printing inks also reduce the comprehensive costs for enterprises to some extent. In long-term production processes, for enterprises with high requirements for production efficiency and environmental protection, using UV printing inks may offer better cost-effectiveness.

There are significant differences between traditional printing ink and UV printing ink in terms of composition, curing principle, printing performance, environmental characteristics, and cost. When choosing ink, it is necessary to comprehensively consider various factors such as the requirements of printing products, production efficiency, environmental regulations, and costs, in order to determine the most suitable ink type, so as to maximize the economic and social benefits of the enterprise while ensuring printing quality.