Raw film for retardation film, retardation film, and liquid-crystal display

A phase difference film and film technology, which is applied in liquid crystal materials, instruments, optics, etc., can solve the problems of film transparency reduction, front contrast reduction, uneven orientation, etc., and achieve the effect of excellent front contrast and low internal turbidity

Inactive Publication Date: 2010-02-10
SUMITOMO CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, according to this method, unevenness in orientation occurs in the width direction of the obtained film, and as a result, unevenness in phase difference and thickness unevenness in the width direction sometimes occur as a result, and it is actually impossible to realize stable production. Films used as retardation films
[0005] In addition, since most polypropylene resins are crystalline plastic materials, in a retardation film made of polypropylene resins, light scattering caused by crystallization of the resin will reduce the transparency of the film, so not only the front contrast reduction, etc., and there is fear that it may have adverse effects on the optical characteristics of liquid crystal display devices

Method used

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  • Raw film for retardation film, retardation film, and liquid-crystal display
  • Raw film for retardation film, retardation film, and liquid-crystal display

Examples

Experimental program
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Effect test

Embodiment 1

[0105] A propylene-ethylene random copolymer (MFR=8g / 10min, ethylene content=4.6% by weight) was added to a 50mmφ extruder with a cylinder temperature set at 250°C for melt kneading, extruding at 13kg / h The output was extruded from a 450 mm wide T-die mounted on the above-mentioned extruder. The extruded molten sheet is nip-cooled by a 250mmφ cooling roll whose temperature is adjusted to 13°C, a metal sleeve (outer cylinder) whose temperature is adjusted to 13°C, and a touch roll composed of an elastomer roll inside. , to obtain a film with a thickness of 100 μm. The nip line pressure at this time was 5 N / mm, and buildup did not occur between the cooling roll and the touch roll. The distance between the discharge port of the T-die and the roll (air chamber) was 20 mm, and the distance between the cooling roll and the touch roll for nipping the sheet was 10 mm. Various samples for evaluation were collected from the films thus obtained. The melting point of the sample was 136...

Embodiment 2

[0110] A propylene-ethylene random copolymer (MFR=1.5g / 10 minutes, ethylene content=5.7% by weight) was added to a 65mmφ extruder with a cylinder temperature set at 240°C for melt kneading at a rate of 46kg / h The extruded amount was extruded from a 1200 mm wide T-die installed in the above-mentioned extruder. The extruded molten sheet is nip-cooled by a 400mmφ cooling roll whose temperature is adjusted to 13°C, a metal sleeve (outer cylinder) whose temperature is adjusted to 13°C, and a touch roll composed of an elastomer roll inside it, A thin film with a thickness of 200 μm was obtained. The air chamber was 150 mm, and the distance between the cooling roll and the touch roll to nip the sheet was 20 mm. Various samples for evaluation were collected from the films thus obtained. The melting point of the sample was 129° C., and the in-plane retardation was 3025 nm. In the entire area of ​​the X-ray diffraction curve of the sample, the ratio of the area under the curve origin...

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Abstract

A film comprising a propylene-based random or block copolymer. It is useful as a raw film for obtaining retardation films through stretching. The copolymer constituting the film has crystals comprising smectic crystals, the proportion of the smectic crystals to all crystals in the copolymer being 90% or higher. This film has an in-plane retardation of 50 nm or less and a thickness of 30-200 ¢mu!m.The copolymer is one forming a film which, when stretched at a pulling rate of 100 mm / min at such a temperature as to result in a stress at 200% strain of 0.8+-0.1 MPa, gives a stress-strain curve inwhich the parameter (A) calculated with the equation (1) is in the range of 0.0007-0.1. (A) = (B600 - B200) / 400 equation (1) (In the equation, B600 and B200 represent stresses (MPa) at strains of 600% and 200%, respectively).

Description

technical field [0001] The present invention relates to a polypropylene-based resin film useful as a material of a retardation film, a retardation film produced from the film, and a liquid crystal display device including the retardation film as an element. Background technique [0002] A liquid crystal display device displays images using electro-optical properties of liquid crystal molecules. However, since liquid crystals inherently have optical anisotropy, optical strain due to birefringence, coloring of displays due to modulation of viewing directions, and the like may occur in liquid crystal display devices. In order to overcome such disadvantages, retardation films are currently used. As a retardation film, a retardation film obtained by stretching a roll film comprising a polycarbonate resin and a cyclic olefin-based polymer is known, but since these material resins are expensive, the development of cheaper plastics is desired. Retardation film formed of materials....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J5/18G02B5/30
CPCC08J2323/14C09K19/544C08J5/18C08J2353/00C09K2219/03C09K19/02G02B5/3083C09K2323/03G02B5/30
Inventor 日野享子铃木俊彦高畑弘明樱井孝至
Owner SUMITOMO CHEM CO LTD
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