Polyester film for optical use and polarizing plate using same

A technology of polyester film and optics, applied in optics, optical elements, polarizing elements, etc., can solve the problems of increased thermal shrinkage, whitening, high retardation, etc., and achieves the effect of excellent whitening resistance

Active Publication Date: 2017-08-29
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, in both Patent Documents 1 and 2, although the interference color when visually viewing the display is suppressed, the retardation in the thickness direction is high, so the suppression of interference color when viewing from an oblique direction is insufficient.
[0004] In addition, in order to suppress the interference color when viewing the display from an oblique direction, a method of reducing the biaxial orientation of the film by adjusting the polymer composition and production conditions was considered. The formation of oriented crystals becomes insufficient, so it is not practical to observe problems such as an increase in thermal shrinkage rate or whitening when heated.

Method used

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  • Polyester film for optical use and polarizing plate using same
  • Polyester film for optical use and polarizing plate using same
  • Polyester film for optical use and polarizing plate using same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0162] Make the composition as shown in the table, supply the raw materials to separate exhaust co-direction twin-screw extruders with the oxygen concentration set to 0.2% by volume, set the barrel temperature of the layer A extruder to 280°C, and extrude the layer B The barrel temperature of the machine is 265°C for melting, and in the feeding area, it is combined in a manner of forming three layers of A layer / B layer / A layer, so that the temperature of the short tube after confluence is 270°C, and the die temperature is The temperature is 275°C, and the sheet is discharged from the T-die onto the cooling drum whose temperature is controlled at 25°C. At this time, static electricity was applied using a wire-shaped electrode with a diameter of 0.1 mm, and it was brought into close contact with a cooling drum to obtain an unstretched sheet. Next, it was preheated for 1.5 seconds at a preheating temperature of 85°C in the longitudinal direction, stretched 3.3 times in the longit...

Embodiment 2

[0164] Except having changed the composition as shown in a table|surface, it carried out similarly to Example 1, and obtained the biaxially-oriented polyester film of thickness 25 micrometers.

Embodiment 3

[0166] The draw ratio in the longitudinal direction is set to 3.5 times, the draw ratio in the width direction is set to 3.8 times, the heat treatment temperature in the first stage is set to 190°C, and the heat treatment temperature in the second stage is set to 228°C. 1 In the same manner, a biaxially oriented polyester film with a thickness of 25 μm was obtained.

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Abstract

The purpose of the present invention is to provide a polyester film that can, although being a biaxially-drawn polyester film, suppress interference colors when the polyester film is installed in a display such as a liquid crystal display and when the display is visually observed, and that is superior in whitening resistance and dimensional stability when being heated. The polyester film, for optical use, of which retardation at a 50-degree tilt angle with respect to the film surface is not larger than 1500 nm, and of which heat of crystallization for temperature-rise (delta Hc) measured by differential scanning calorimetry (DSC) is not more than 15 J/g.

Description

technical field [0001] The present invention relates to an optical polyester film and a polarizing plate. Background technique [0002] Thermoplastic resin films, especially biaxially oriented polyester films, have excellent properties such as mechanical properties, electrical properties, dimensional stability, transparency, and chemical resistance, so they are used as base films in many applications such as magnetic recording materials and packaging materials being widely used. In particular, in recent years, in the field of flat panel displays and touch panels, the demand for various optical films such as polarizer protective films and transparent conductive films has increased. Among them, in the use of polarizer protective films, the aim is to reduce costs. , The replacement of the conventional TAC (triacetyl cellulose) film to the biaxially oriented polyester film was studied. Biaxially oriented polyester film is caused by the orientation of the polymer during stretch...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J5/18B32B7/02B32B27/36G02B1/11G02B1/14G02B1/16G02B5/30
CPCB32B27/36C08J5/18G02B1/11G02B5/30G02B1/14G02B1/16G02B5/305B32B2551/00
Inventor 真锅功盐见笃史坂本光隆高田育
Owner TORAY IND INC
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