How can gravity water-based ink achieve uniform and strong adhesion printing on the different surfaces of clothing and courier bags?
Release Time : 2025-12-18
With green packaging and sustainable fashion becoming mainstream trends in the industry, gravure water-based ink are gradually replacing traditional solvent-based inks and occupying an important position in the gravure printing field. Achieving uniform spreading, rich color, and strong adhesion when printing on substrates with vastly different characteristics, such as clothing and courier bags, is a major challenge.
1. Intelligent Adaptation of Ink Formulation: Balancing Wetting and Film Formation
The successful application of gravity water-based ink relies primarily on the resin system and additive combination in its formulation design. For low surface energy materials, such as PE/PP courier bags, highly efficient wetting and dispersing agents and adhesion promoters, such as chlorinated polyolefin emulsions or modified acrylic resins, need to be added to the ink to reduce the surface tension of the ink, thereby ensuring that the ink can spread naturally on these surfaces without shrinkage. Meanwhile, selecting a core-shell structured acrylic emulsion as the film-forming resin allows for the formation of a continuous and flexible paint film, while also enhancing the anchoring effect on non-polar plastics through molecular chain segment design.
For porous, highly hydrophilic clothing materials, such as non-woven fabrics, the key is controlling the ink penetration rate. Excessive absorption can lead to "back-through" phenomena or uneven coloring, while excessively slow absorption affects drying efficiency. Therefore, the ratio of rheology modifiers and solids content in the formulation needs to be adjusted to ensure moderate penetration of the ink upon contact with the fibers. This strengthens mechanical interlocking while retaining sufficient pigment on the surface to ensure color density.
2. Substrate Pretreatment: Opening the "First Mile" of Adhesion
Even with advanced ink formulations, the surface tension of untreated PP/PE express bags is typically only 30-32 mN/m, far below the minimum wetting requirement of water-based inks—above 38 mN/m. Therefore, corona treatment becomes an essential step. Introducing polar groups such as hydroxyl and carboxyl groups onto the material surface through high-voltage discharge can increase the surface tension to 42-48 mN/m, significantly improving the wetting and chemical bonding of the ink.
For clothing fabrics, although they possess some hydrophilicity, they may contain spinning oils or antistatic coatings, which can actually hinder ink adhesion. In such cases, light cleaning or plasma pretreatment is necessary to remove impurities and activate the fiber surface, ensuring direct contact between the ink and the actual substrate, thereby improving adhesion.
Achieving high-quality printing results with gravity water-based ink on two vastly different materials—clothing and courier bags—requires not only carefully designed ink formulations but also appropriate substrate pretreatment measures. Only through systematic collaborative work can the challenges posed by material differences be overcome, driving the development of green packaging and sustainable fashion.
1. Intelligent Adaptation of Ink Formulation: Balancing Wetting and Film Formation
The successful application of gravity water-based ink relies primarily on the resin system and additive combination in its formulation design. For low surface energy materials, such as PE/PP courier bags, highly efficient wetting and dispersing agents and adhesion promoters, such as chlorinated polyolefin emulsions or modified acrylic resins, need to be added to the ink to reduce the surface tension of the ink, thereby ensuring that the ink can spread naturally on these surfaces without shrinkage. Meanwhile, selecting a core-shell structured acrylic emulsion as the film-forming resin allows for the formation of a continuous and flexible paint film, while also enhancing the anchoring effect on non-polar plastics through molecular chain segment design.
For porous, highly hydrophilic clothing materials, such as non-woven fabrics, the key is controlling the ink penetration rate. Excessive absorption can lead to "back-through" phenomena or uneven coloring, while excessively slow absorption affects drying efficiency. Therefore, the ratio of rheology modifiers and solids content in the formulation needs to be adjusted to ensure moderate penetration of the ink upon contact with the fibers. This strengthens mechanical interlocking while retaining sufficient pigment on the surface to ensure color density.
2. Substrate Pretreatment: Opening the "First Mile" of Adhesion
Even with advanced ink formulations, the surface tension of untreated PP/PE express bags is typically only 30-32 mN/m, far below the minimum wetting requirement of water-based inks—above 38 mN/m. Therefore, corona treatment becomes an essential step. Introducing polar groups such as hydroxyl and carboxyl groups onto the material surface through high-voltage discharge can increase the surface tension to 42-48 mN/m, significantly improving the wetting and chemical bonding of the ink.
For clothing fabrics, although they possess some hydrophilicity, they may contain spinning oils or antistatic coatings, which can actually hinder ink adhesion. In such cases, light cleaning or plasma pretreatment is necessary to remove impurities and activate the fiber surface, ensuring direct contact between the ink and the actual substrate, thereby improving adhesion.
Achieving high-quality printing results with gravity water-based ink on two vastly different materials—clothing and courier bags—requires not only carefully designed ink formulations but also appropriate substrate pretreatment measures. Only through systematic collaborative work can the challenges posed by material differences be overcome, driving the development of green packaging and sustainable fashion.