High-strength and two-way-stretching PEN film and preparation method thereof

Abstract

The invention discloses a high-strength and two-way-stretching PEN film and a preparation method thereof. The film is composed of an upper surface layer, a core layer and a lower surface layer, wherein the thickness of the film is 20-50 microns, the tensile strength is 350 Mpa or above, the hydrolysis resisting performance is up to 200 h or above, and the longitudinal and horizontal heat shrinkage rate is 0.4% or below under the conditions of the temperature of 150 DEG C and the time of 30 minutes. The core layer consists of a toughening agent and a polyethylene naphthalate slice, wherein the toughening agent content is 0.01-5% by weight. The upper surface layer and the lower surface layer are composed of polyethylene naphthalate slices and an anti-sticking agent, wherein the anti-sticking agent content is 0.01-5% by weight. The high-strength and two-way-stretching PEN film prepared by adopting a three-layer co-extrusion and two-way stretching process has the advantages of being large in tensile strength, resistant to hydrolysis and corrosion, high in thermal stability and the like.

Description

technical field [0001] The invention relates to the technical field of films, in particular to a high-strength biaxially stretched PEN film and a preparation method thereof. Background technique [0002] Polyethylene naphthalate (PEN) is a polymer with excellent physical properties. Its molecular chain has a large rigidity and a planar structure, so its mechanical, electrical, and chemical properties are very good. Specifically, there are : High strength, good dimensional stability and thermal stability, strong chemical resistance and hydrolysis resistance, etc. [0003] PEN film has outstanding heat resistance, dimensional stability, long-term durability, and airtightness, but its gas permeability and water absorption are lower than those of polyimide film. In the field of flexible printed circuit (FPC) for automobiles, PEN can be used to replace polyimide (PI) due to its outstanding performance and lower cost than polyimide film. At present, Europe has begun to use PEN f...

AI Technical Summary

Problems solved by technology

[0005] At present, most of the PEN films in the domestic market are made by casting method, and although the mechanical properties of PEN films made by casting method are greatly improved compared with high-temperature resistant polyester film (PET), the uniformity of thickness is poor, and it is different from imported films. Compared with biaxially stretched PEN film, there is a big gap, especially in terms of tensile strength and thermal stability.

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