The surface treatment of aluminum foil tissue paper requires a synergistic effect of physical modification, chemical treatment, and composite processes to enhance its friction with the aluminum foil tissue paper, while simultaneously ensuring hygiene, durability, and user comfort. This process involves four dimensions: surface roughness control, chemical activity enhancement, microstructure optimization, and the application of functional coatings, ensuring stable mechanical interlocking and intermolecular forces between the aluminum foil and the aluminum foil tissue paper upon contact.
Physical modification is the fundamental means of enhancing friction. Through mechanical embossing or sandblasting, regular or random micro-protrusions can be formed on the aluminum foil surface. These structures increase the actual contact area, making it easier for the aluminum foil tissue paper fibers to embed into the grooves, thereby enhancing mechanical interlocking force. For example, using a diamond or grid-like embossing pattern ensures uniform distribution of friction while preventing damage to the aluminum foil tissue paper due to localized stress concentration. Furthermore, controlling the embossing depth and spacing is crucial; too deep an embossing may reduce the strength of the aluminum foil, while too shallow an embossing will result in insufficient friction.
Chemical treatment enhances adsorption capacity by altering the surface chemical properties of the aluminum foil. Plasma cleaning technology can remove the oxide layer and organic contaminants from the surface of aluminum foil, while introducing oxygen- or nitrogen-containing functional groups. These polar groups can form hydrogen bonds or van der Waals forces with cellulose molecules in the aluminum foil tissue paper, significantly improving interfacial bonding strength. Chemical etching is another commonly used method, selectively dissolving the aluminum foil surface with acidic or alkaline solutions to form micro- or nano-scale porous structures. This structure not only increases surface roughness but also adsorbs aluminum foil tissue paper fibers through capillary action, further enhancing friction.
Microstructure optimization requires incorporating biomimetic principles. Inspired by the superhydrophobic structure of lotus leaf surfaces, micron-scale papillary structures can be constructed on the aluminum foil surface through laser processing or template methods. These structures reduce the contact area between the aluminum foil and the aluminum foil tissue paper while enhancing friction through mechanical interlocking effects. Unlike simply increasing roughness, biomimetic structures can achieve a high coefficient of friction under low pressure, making them particularly suitable for applications requiring frequent pulling and stretching of aluminum foil tissue paper. Furthermore, this structure possesses self-cleaning properties, preventing aluminum foil tissue paper debris from remaining and affecting the user experience.
Functional coatings are an effective supplement to enhance friction. Waterborne polyurethane or acrylic coatings can form a soft and elastic film on the aluminum foil surface. This coating increases surface adhesion and cushions the impact during pulling, preventing damage to the aluminum foil tissue paper. Some coatings also incorporate silica or calcium carbonate particles to further enhance friction by increasing surface roughness. When selecting coatings, both hygiene and environmental friendliness must be considered to ensure compliance with food contact material standards. Additionally, coating thickness must be precisely controlled; excessive thickness may reduce the flexibility of the aluminum foil, while insufficient thickness will result in inadequate friction.
Multi-process synergy can maximize friction enhancement. For example, a basic rough structure can be formed first through chemical etching, then surface chemical activity can be activated using plasma cleaning, and finally, a functional coating can be applied to fill minor defects. This composite processing method ensures both mechanical interlocking between the aluminum foil and the aluminum foil tissue paper and enhances the bonding strength through intermolecular forces. In actual production, process parameters need to be adjusted according to the aluminum foil thickness, aluminum foil tissue paper material, and usage scenario to ensure a balance between friction and durability.
The surface treatment effect must undergo rigorous testing and verification. The coefficient of friction test is a core indicator, requiring simulation of real-world usage scenarios to evaluate the dynamic frictional performance of the aluminum foil and aluminum foil tissue paper. Furthermore, the corrosion resistance, temperature resistance, and hygiene indicators of the treated aluminum foil must be tested to ensure compliance with relevant standards. For example, chemically treated aluminum foil must undergo salt spray testing to verify its corrosion resistance, while functional coatings must be tested for excessive heavy metal content.
Environmental protection and sustainability are crucial considerations for surface treatment. Traditional chemical treatments may generate wastewater pollution, while dry treatment technologies such as plasma cleaning are more environmentally friendly. In addition, choosing water-based coatings instead of solvent-based coatings can reduce volatile organic compound emissions. Some companies are also using biodegradable coating materials to further enhance the environmental friendliness of their products. In the future, with the development of nanotechnology and bio-based materials, aluminum foil surface treatment will evolve towards greater efficiency and greener practices.
