UNIAXIALLY STRETCHED MULTILAYER LAMINATED EASILY-ADHESIVE FILM AND OPTICAL MEMBER USING THE SAME

• Main Authors: YOSHIMURA CHIKA, OKUMURA HISAO, NAKAGAWA MASARU, TANABE KANA
• Format: Patent
• Language: English; Japanese
• Published: 18.05.2017
• Subjects: LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; PERFORMING OPERATIONS; TRANSPORTING

PROBLEM TO BE SOLVED: To provide an uniaxially stretched multilayer laminated easily-adhesive film which has high adhesion between an optical layer such as a prism layer and a diffusion layer formed on a film and the film, in addition to reflection polarization performance, in a multilayer film, and to provide an optical member using the same.SOLUTION: There is provided an uniaxially stretched multilayer laminated easily-adhesive film in which a first layer and a second layer are alternately laminated, where 1) the first layer is a layer that contains polyester as a main component, and contains a range of 50 mol% or more and 100 mol% or less of an ethylene naphthalate unit based on a repeating unit constituting the polyester, 2) the second layer is a layer that contains copolymerized polyester as a main component, where the copolymerized polyester has a glass transition temperature of 85°C or higher and an average refractive index of 1.55-1.65, 3) the total of alternate laminate numbers of the first layer and the second layer is 101 or more layers in total, where the film has an outermost layer having a thickness of 5-50 μm formed from the second layer on at least one surface, 4) the film has an easily adhesive layer having a thickness of 0.01-0.50 μm on the outer surface of at least one outermost layer, where the easily adhesive layer contains a polyurethane resin and 0.5-6.0 wt.% of particles having an average particle size of 0.4-0.8 μm with respect to the weight of the easily adhesive layer, 5) the thickness of the whole film containing the easily adhesive layer is 20-150 μm, and 6) an average value of a degree of polymerization determined at 5 nm interval is 70% or more in a wavelength range of 380-780 nm.SELECTED DRAWING: None 【課題】多層フィルムにおいて、反射偏光性能に加え、フィルム上に形成するプリズム層や拡散層等の光学層とフィルムとの間の高い密着性を備えた１軸延伸多層積層易接着フィルム、およびそれを用いた光学部材を提供すること。【解決手段】第１層と第２層とが交互に積層された１軸延伸多層積層易接着フィルムであって、１）該第１層はポリエステルを主たる構成成分とする層であって、該ポリエステルを構成する繰り返し単位を基準としてエチレンナフタレート単位を５０モル％以上１００モル％以下の範囲で含有し、２）該第２層は共重合ポリエステルを主たる構成成分とする層であって、該共重合ポリエステルは８５℃以上のガラス転移温度を有し、平均屈折率が１．５５〜１．６５であり、３）該第１層と該第２層の交互積層数が合計で１０１層以上であり、かつ少なくとも一方の面に第２層からなる厚み５〜５０μｍの最外層を有し、４）少なくとも一方の前記最外層の外側表面に厚み０．０１〜０．５０μｍの易接着層を有し、該易接着層はポリウレタン樹脂、および平均粒径０．４〜０．８μｍの粒子を該易接着層の重量に対して０．５〜６．０重量％含有し、５）該易接着層を含めたフィルム全体厚みが２０〜１５０μｍであって、６）３８０〜７８０ｎｍの波長範囲において、５ｎｍ間隔で求めた偏光度（Ｐ）の平均値が７０％以上である、１軸延伸多層積層易接着フィルム。【選択図】なし