RETARDATION FILM AND METHOD FOR PRODUCING RETARDATION FILM

• Main Authors: TOGAWA HITOMI, NEMOTO TOMOYUKI
• Format: Patent
• Language: English; Japanese
• Published: 18.01.2018
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; METALLURGY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; ORGANIC MACROMOLECULAR COMPOUNDS; PHYSICS; THEIR PREPARATION OR CHEMICAL WORKING-UP

PROBLEM TO BE SOLVED: To provide a retardation film formed by mixing resins having different intrinsic birefringence, which has flat wavelength dispersibility or reverse wavelength dispersibility in a wavelength region of visible light and is excellent in transparency, and to provide a method for producing such a retardation film.SOLUTION: The retardation film comprises a norbornene polymer (A) having positive intrinsic birefringence and has a norbornene monomer unit as a structural unit and a polymer (B) having negative intrinsic birefringence and mainly contains a (meth)acrylate unit as a structural unit, where a ratio of the norbornene monomer unit in the total structural units of the norbornene polymer (A) is 65 wt.% or more, the norbornene polymer (A) and the polymer (B) are contained in a specific ratio, and in-plane retardation Re (446 nm), Re (547 nm) and Re (749 nm) measured at measurement wavelengths of 446 nm, 547 nm and 749 nm satisfy a specific relationship.SELECTED DRAWING: Figure 1 【課題】 固有複屈折の異なる樹脂の混合し形成される位相差フィルムであって、可視光の波長領域内で平坦な波長分散性、または逆波長分散性を有し、透明性に優れる位相差フィルムと、そのような位相差フィルムの製造方法の提供。【解決手段】 正の固有複屈折を有し、構造単位としてノルボルネン系単量体単位を有するノルボルネン系重合体（Ａ）と、負の固有複屈折を有し、構造単位として（メタ）アクリル酸エステル単位を主成分とする重合体（Ｂ）を含み、前記ノルボルネン系重合体（Ａ）の全構成単位に占める前記ノルボルネン系単量体単位の割合が、６５重量％以上であり、前記ノルボルネン系重合体（Ａ）と前記重合体（Ｂ）が特定の比率で含まれており、測定波長４４６ｎｍ、５４７ｎｍおよび７４９ｎｍで測定した面内位相差Ｒｅ（４４６ｎｍ）、Ｒｅ（５４７ｎｍ）およびＲｅ（７４９ｎｍ）が特定の関係を満たす位相差フィルム。【選択図】 図１