Ink is an indispensable material in the printing process, and its performance directly affects the quality and effect of printed matter. Ink is mainly composed of pigments, binders, additives and solvents, etc. Among them, the binder (also known as the color developer or color carrier) is one of the core components of ink and plays a key role.
The binder is the liquid part of the ink, and its main functions include:
Dispersing and carrying pigments: The binder evenly disperses the pigments, keeping them stably suspended to ensure uniform and consistent ink color.
The rheological properties of ink are determined: The viscosity, fluidity and drying characteristics of the binder directly affect the printability of the ink, such as transferability, adhesion and drying speed.
Affecting the adhesion of ink: The binder enables the ink to firmly adhere to the surface of the substrate, preventing it from peeling off or wearing.
Adjust the drying method: Depending on the printing process, the binder can be dried through methods such as oxidation polymerization, volatilization, penetration or photopolymerization.
Ii. Types of Ink Binders
According to the differences in composition and application, ink binders are mainly classified into the following categories:
Vegetable oil binders: such as linseed oil, tung oil and other drying oils, are often used in offset printing inks and dry through oxidation polymerization.
Resin binders: including natural resins (such as rosin) and synthetic resins (such as phenolic resin, polyurethane), can enhance the gloss and wear resistance of inks.
Solvent-based binders: such as benzene and ketone solvents, are used in gravure and flexographic printing inks and dry by the evaporation of solvents.
Water-based binder: Using water as the solvent, it is environmentally friendly and non-toxic, suitable for food packaging and flexographic printing.
Uv-curable binders: such as acrylic resins in UV inks, which cure rapidly under ultraviolet light and are suitable for high-speed printing.
Iii. Selection of Binder
The selection of binder should take into account the printing method, substrate material and environmental protection requirements comprehensively. For instance, offset printing inks often use high-viscosity resin binders, while flexographic printing tends to employ low-viscosity water-based binders.
In conclusion, the ink binder is a key factor determining the performance of the ink, and its reasonable proportion and selection are of vital importance to the printing quality. With the increasing environmental protection requirements, water-based binders and UV-curable binders will become the mainstream trends in future development.
