Polyester film without anti-blocking agent and preparation method of polyester film

Abstract

The invention discloses a polyester film without an anti-blocking agent and a preparation method of the polyester film. The polyester film is characterized by being prepared from polyester without theanti-blocking agent. The preparation method includes steps: subjecting the polyester without the anti-blocking agent to pre-crystallization and drying at a temperature of 160-180 DEG C, feeding intoan extruder to realize melting at a temperature of 275-290 DEG C, filtering through a filter, extruding into flaky melt through a single-layer or multi-layer mould head, and cooling on a cooling drumat a temperature of 20-25 DEG C to obtain a polyester sheet material; soaking the prepared polyester sheet material in an airtight container filled with supercritical carbon dioxide for 10-25min, taking out, preheating in a tank filled with organic solution at a temperature of 80-140 DEG C for 5-20s, and stretching to obtain the polyester film without the anti-blocking agent. The film is excellentin performance and applicable to manufacturing of film products such as liquid crystal displays, touch screens, ceramic capacitors and decorative packages.

Description

technical field [0001] The invention belongs to polyester film and its preparation, and relates to an anti-blocking agent-free polyester film and its preparation method. The anti-blocking agent-free polyester film prepared by the invention can be used in the manufacture of film products such as liquid crystal displays, touch screens, ceramic capacitors, and decorative packaging. Background technique [0002] Polyester film has the characteristics of transparency, temperature resistance, and good mechanical properties. It is widely used in liquid crystal display, touch screen, ceramic capacitor, decorative packaging and other fields, such as: used for various release, protection, diffusion, brightening, hardening, ITO , IMD, solar battery backplane, window film, ceramic capacitor and other functional film substrates. [0003] Microparticle fillers are usually added to the surface of the polyester film as an anti-blocking agent. The anti-blocking agent usually protrudes from ...

AI Technical Summary

Problems solved by technology

Otherwise, the gap between the film layers is extremely small, the friction coefficient is extremely large, and it is impossible to slide and separate, and subsequent winding and processing will be difficult.

[0004] At present, anti-blocking agents are generally non-polyester materials, such as: silicon dioxide, barium sulfate, calcium carbonate, PMMA, etc., wherein silicon dioxide is the most commonly used, which leads to the following problems: (1) The refractive index and density of these anti-blocking agents It is often different from polyester film. When light passes through polyester film, there will be more scattering and reflection at the interface, resulting in decreased light transmittance, decreased clarity and increased haze, affecting optical quality. performance; (2) these anti-blocking agents are incompatible with polyester, and there is a significant difference in surface energy, and there is also a significant difference in the interface between the two; due to the difference in surface energy, during the melting process, the anti-blocking agent will It is very easy to have uneven distribution in the medium, which will affect the uniformity and stability of optical and mechanical properties. At the same time, due to the obvious differences in the interface, on the one hand, when the external force is applied, the interface will form a stress concentration point, resulting in mechanical properties at this place. The position is poor. On the other hand, the interface has a large difference. When stretching the film, there will be phase separation, and there will be orange peel on the film surface, which will affect the appearance of subsequent products.

[0005] In the prior art, the usual solutions are as follows: one is to reduce the particle size of the added anti-blocking agent powder, such as using a nano-scale anti-blocking agent to minimize scattering and reflection, but the smaller the particle, the more difficult it is to gather Uniform dispersion in ester

The second is to coat the surface of the polyester film with a coating containing nanoparticles. The dispersion of nanoparticles in the coating is better, but there are high requirements for the coating formulation and coating thickness control, and the manufacturing cost is increased.

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