Method for manufacturing optical film, optical film, polarizing plate, and liquid crystal display device

By preparing a paste containing specific cellulose ester resin and sugar ester, casting film preparation, and stretching under specific conditions, the problem of uneven display of wide-width optical films under environmental changes was solved, and high-performance optical films were manufactured.

CN117047953BActive Publication Date: 2026-08-04KONICA MINOLTA INC
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Patent Information

Application Number
CN202310511172.4
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Priority Date
2022-05-12
Filing Date
2023-05-08
Publication Date
2026-08-04
Estimated Expiration
2043-05-08

AI Technical Summary

Technical Problem

Existing technologies make it difficult to manufacture wide-format optical films using plant-based resins, and these films are prone to uneven image display under environmental changes.

Method used

An optical film with small in-plane and thickness retardation values ​​is manufactured by preparing a paste containing specific cellulose ester resin and sugar ester, using a casting film preparation method, and stretching under specific conditions. This method includes two stretching processes and high-temperature stretching temperature control.

Benefits of technology

The manufacturing of a wide-width optical film that suppresses uneven image display under environmental changes has been achieved, improving the dimensional stability and optical performance of the film, making it suitable for large display devices.

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Abstract

This invention relates to a method for manufacturing an optical film, an optical film, a polarizer, and a liquid crystal display device. The objective is to provide a method for manufacturing a wide-width optical film with low retardation values ​​in both the in-plane and thickness directions, and to suppress display unevenness caused by environmental variations in the display device, using a plant-derived resin. The method for manufacturing the optical film of this invention is characterized by comprising: a step of forming a strip film from a cellulose ester resin containing a total acetyl substitution degree of 2.30 to 2.60 and a sugar ester having a furanose or pyranose structure; and a step of stretching said strip film, wherein the retardation value R... o The range is 0–10 nm, R t The process of stretching the long strip film, with a wavelength of -10 to 10 nm, includes the following steps: a first step to obtain a first stretched film; and a second step to further stretch the first stretched film to obtain a second stretched film, wherein the stretching temperature of the second step is in the range of 190 to 220°C.
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