Ink Binder is an important component of ink, responsible for carrying pigments, providing printability, and influencing the drying performance and adhesion of ink. Its development process is closely related to the progress of printing technology, environmental protection requirements and materials science. It can roughly be divided into three stages: traditional type, synthetic resin type and environmentally friendly type.
The traditional binder stage (early to mid-20th century)
In the early days, ink binders mainly relied on natural materials, such as drying vegetable oils (flaxseed oil, tung oil, etc.) and mineral oils. This type of binder is dried through oxidation polymerization or penetration and is suitable for letterpress and offset printing. Its advantages are that the raw materials are readily available and the cost is low, but the drying speed is slow, the gloss is poor, and it is easily affected by the environmental temperature and humidity. At the beginning of the 20th century, with the increase in printing speed, natural resins (such as rosin derivatives) were introduced to improve drying and film-forming properties, but there was still the problem of insufficient stability.
2. The synthetic resin binder stage (mid-to-late 20th century)
With the development of petrochemicals, synthetic resins (such as phenolic resins, polyurethane, acrylic resins, etc.) have gradually replaced natural materials. This type of binder can adjust its viscosity, adhesion and drying speed through chemical modification to adapt to high-speed printing (such as offset printing and gravure printing). For instance, thermosetting binders utilize high-temperature instantaneous drying, significantly enhancing production efficiency. In addition, solvent-based binders (using benzene and ester solvents) once became mainstream, but the problem of their volatile organic compound (VOC) emissions has gradually emerged.
3. The stage of environmentally friendly binders (21st Century to present
Under the impetus of environmental protection regulations (such as the EU REACH and the US EPA standards), binders are developing towards a low-pollution direction. Water-based binders use water as the solvent and have extremely low VOC emissions, making them suitable for flexographic and gravure printing. Ultraviolet (UV) and electron beam (EB) curing binders initiate polymerization through radiation, achieving second-level drying without solvent residue. In addition, bio-based binders (such as soybean oil and lactate esters) have regained attention, taking into account both renewability and degradability. In recent years, nanotechnology has also been used to enhance the rheological properties and wear resistance of binders.
Future trends
In the future, binders will pay more attention to the balance between functionality and sustainability, such as developing low-temperature curing, recyclable ink systems, or using biotechnology to synthesize high-performance resins. Meanwhile, the popularization of digital printing may drive the development of binders towards personalization (such as conductive inks).
