Transparent polyimide hardened film with low shrinkage, high hardness and high wear resistance

Abstract

The invention specifically relates to a transparent polyimide hardened film with low shrinkage, high hardness and high wear resistance, belonging to the technical field of transparent polyimide hardened films. A hardening solution used for preparing the transparent polyimide hardened film comprises, by weight, 50-80 parts of high-functionality urethane acrylate, 10-20 parts of polyfunctional polyether acrylate, 10-20 parts of a flexible monomer, 10-20 parts of a reactive diluent, 0.5-2 parts of a photoinitiator, 0.05-0.2 part of a thermal initiator, 80-150 parts of a good solvent, 2-20 parts of a high-boiling-point poor solvent, 0.05-1 part of an anti-fingerprint agent and 10-30 parts of inorganic nanoparticles. According to the invention, the high-functionality urethane acrylate and the polyfunctional polyether acrylate are adopted to improve the hardness of the hardened film, and the toughness of the hardened film is enhanced by the flexible monomer; and the thermal initiator and thephotoinitiator are added at the same time, and through cooperation between thermal curing and photocuring, shrinkage stress caused by polymerization during curing process is properly released, so warpage is avoided.

Description

technical field [0001] The invention belongs to the technical field of transparent polyimide cured film, in particular to a transparent polyimide cured film with low shrinkage, high hardness and high wear resistance. Background technique [0002] Curved screen technology has been widely valued and sought after by consumers and the industry in recent years. In the future, with the continuous development and improvement of fixed-curvature curved screen technology, flexible touch screens that can be bent arbitrarily will become an important development direction. Although the flexible screen can be bent, if it is bent frequently, it will have the same fatigue problem as metal paper. If it is bent multiple times and used for a long time, the flexible screen may be damaged by creases in the middle of the screen after being subjected to multiple compression and tensile stresses. In addition, circuit boards, components, after being subjected to a lot of bending and non-bending, m...

AI Technical Summary

Problems solved by technology

If it is bent multiple times and used for a long time, after the flexible screen is subjected to multiple compression and tensile stresses, crease damage may appear in the middle of the screen

In addition, circuit boards, components, after being subjected to a lot of bending and non-bending, may also cause damage or other failures during folding

The existing glass panel cannot meet its high frequency requirements, and the transparent polyimide (CPI) film is used to replace the existing glass cover plate because of its good foldability, but polyimide (PI ) The material cannot meet the hardness requirements, and it is necessary to add a hardened film on the surface of the PI film to enhance the hardness

[0003] At present, there are two main problems in the research and development of flexible screen hardening film: one is the contradiction between high hardness and low warpage. Linkage, while conventional vinyl monomers will cause volume shrinkage during the UV curing process, the greater the degree of crosslinking, the more serious the volume shrinkage; the second is the contradiction between high hardness and bendability, through a large number of high-functionality monomers After increasing the cross-linking density to obtain high hardness, the hardened film is usually brittle, and it needs to be properly matched with flexible monomers to improve toughness, and the structure and quantity of flexible monomers will affect whether the hardened film can finally have good bendability. very important

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