Because of its own characteristics, PET substrate makes it difficult for water-based acrylic resin to have good adhesion on its surface, especially for optical-grade transparent PET film, which has a smooth surface and is not easy to adhere to. Corona treatment can make the surface tension value around 40mN/m, but it can not solve the problem of the adhesion of acrylic resin on its surface, and the surface of the corona film is time-sensitive, with the extension of time, the corona effect will gradually Therefore, it is a difficult problem to solve the adhesion problem of acrylic resin on the surface of the film. The following is the solution obtained through practical application.
The essential reason for poor adhesion is the resin. Polyurethane can adhere well to the surface of the film, while acrylic resin is difficult to adhere to. Although polyurethane has good adhesion, the surface of the coating is not scratch-resistant and has insufficient hardness. Therefore, in view of their respective advantages and disadvantages, it is difficult to use a single resin to achieve the effect of film coating.
Therefore, there are several ways to improve the adhesion of water-based acrylic resins:
1. Modify the acrylic resin to improve the hardness and the adhesion on the PET substrate.
2. The method of adding a coupling agent can improve the adhesion between the substrate and the coating. Adding additives can improve the adhesion to a certain extent, but the degree of improvement is limited and far from meeting the requirements.
3. The way of physical blending of water-based acrylic-polyurethane copolymer with core-shell structure and polyurethane resin, single modified resin can not achieve the ideal state at present, but by re-introducing polyurethane resin with strong adhesion, it can make The adhesion of the coating reaches a 5B rating.
Through the above methods, the adhesion of water based acrylic resin will be greatly improved
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