The essential reason for the poor adhesion is the resin. Polyurethane can adhere well to the surface of the film, while acrylic resin is difficult to adhere. Although polyurethane has good adhesion, the coating surface is not scratch resistant and the hardness is not enough. 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 resin:

1. Modify the acrylic resin to increase the hardness and at the same time increase the adhesion to the PET substrate. At present, the mechanical properties of the coating are improved by means of organic silicon modification, and the surface scratch resistance and hardness of the coating obtained are significantly improved, and the hardness can reach 2H, but the surface tension after the organic silicon modification is greater. As the hardness increases, The brittleness of the coating is improved and the adhesion is worse.

Another modification method uses core-shell polymerization technology to graft acrylic resin onto the polyurethane chain to obtain a water-based acrylic-polyurethane copolymer with a certain core-shell structure, which solves the contradiction between low-temperature film formation and hardness, and improves the resin At the same time of adhesion, it has good abrasion resistance and impact resistance, and at the same time avoids the problem of poor physical blending compatibility of acrylic resin and polyurethane resin. This method is currently the root solution for adhesion. The Dow currently used in the market The adhesion of the product on the film is still limited and can reach 4B.

2. The method of adding 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, which is far from meeting the requirements.

3. The physical blending of the water-based acrylic-polyurethane copolymer with core-shell structure and the polyurethane resin, a single modified resin can not achieve the ideal state at present, but by reintroducing a polyurethane resin with strong adhesion, it can make The adhesion of the coating reaches the level of 5B, and there is no coating falling off the periphery of the 100-grid test. At the same time, the hardness and toughness are very good, and the winding can be carried out well. The disadvantage of this method is that before use, it is necessary to strictly test the compatibility of the two resins and select the same type of resin.

Having introduced so much, I believe that everyone has a certain understanding of acrylic resins. If you want to know more about and cooperation matters, please contact Heshan KBORON New Material Co., Ltd.

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