Colorless transparent polyimide film

Abstract

The invention belongs to the technical field of functional films, and particularly relates to a colorless transparent polyimide film which comprises a substance A and a substance B. The substance A isa nitrate inorganic filler; the substance B is an anhydride-terminated polyamic acid resin obtained by carrying out condensation polymerization on a diamine and a dianhydride; the substance A and thesubstance B are blended and subjected to biaxial stretching and imidization treatment to obtain the polyimide film; the nitrate inorganic filler accounts for 0.1wt%-7.2wt% of the total weight of thepolyimide film. The beneficial effects of the invention are that: the solvent soluble nitrate inorganic filler is added, and the inorganic filler in the colorless transparent polyimide synthesis process is ensured not to reduce the mechanical property, the thermal property (shrinkage rate, thermal expansion coefficient and the like) and the insulating property (electrical strength, dielectric constant and the like) of the film, and achieve the high refractive index and the low birefringence parameter of the colorless transparent polyimide film, the market requirement can be better met, and theproduct application field is expanded.

Description

technical field [0001] The invention belongs to the technical field of functional films, in particular to a colorless and transparent polyimide film. Background technique [0002] In the future, the development of optoelectronic devices will gradually show the trend of light weight, large size, ultra-thin and flexible. As a traditional transparent substrate material, glass can no longer meet the development requirements of future flexible packaging technology. With the advantages of transparency, flexibility, light weight, and high impact resistance, it has become the first choice for flexible optoelectronic packaging substrate materials in the future. Polyimide film has excellent heat resistance and stability, which can meet the requirements of high temperature processes such as electrode film deposition and annealing treatment in the process of optoelectronic device processing. Therefore, the development of high transparency polyimide materials has become the focus of rese...

AI Technical Summary

Problems solved by technology

At present, researchers at home and abroad are using the above-mentioned structural monomers and combining them to develop new formulas, and preparing high light transmittance, high modulus, relatively high glass transition temperature (Tg) and relatively low Colorless and transparent polyimide film with CTE and low heat shrinkage, but the comprehensive performance improvement of the film is limited, such as high haze, low refractive index, high birefringence, low surface hardness and other defects.

Even if the polymerized monomer and solvent are refined and pretreated before the polymerization is carried out, the improvement of its comprehensive performance is greatly limited.

In addition, in the prior art, some high molar refractive index groups are introduced through molecular structure design, that is, increasing the rigid segment to endow it with high refractive index, and at the same time endow it with high heat resistance stability, high mechanical properties and dielectric properties. Although the method can further increase the refractive index of polyimide, the improvement is limited. At the same time, if too many rigid segments are introduced, there will be abnormalities such as increased birefringence, decreased light transmittance, and increased yellowing index.

Furthermore, due to the excessive retention of flexible chain links, the thermal stability and mechanical properties of polyimide will decrease to a certain extent.

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