KR-20260066046-A - Laminated optical film and image display device

KR20260066046AKR 20260066046 AKR20260066046 AKR 20260066046AKR-20260066046-A

Abstract

A laminated optical film comprising at least an acrylic film and a first optical film laminated with an adhesive layer interposed therein, wherein the adhesive layer is formed as a cured layer of an adhesive composition containing at least a polymerizable compound, the acrylic film and the adhesive layer have a structure in direct contact, and the logPow representing the octanol/water partition coefficient based on the weighted average of the mole fraction of the polymerizable compound contained in the adhesive composition is 1.8 or higher and 3.0 or lower, and the elastic modulus of the adhesive layer is 1× 10⁵ Pa or higher and 3× 10⁶ Pa or lower.

Inventors

와키 슈타
사사가와 타이스케
미타 사토시

Assignees

닛토덴코 가부시키가이샤

Dates

Publication Date: 20260512
Application Date: 20240704
Priority Date: 20230907

Claims (10)

As a laminated optical film in which at least an acrylic film and a first optical film are laminated with an adhesive layer interposed therebetween, The above adhesive layer is formed as a cured layer of an adhesive composition containing at least a polymerizable compound, and The above acrylic film and the above adhesive layer have a structure in direct contact, and The logPow representing the octanol/water partition coefficient based on the weighted average of the mole fractions of the polymerizable compounds contained in the adhesive composition is 1.8 or higher and 3.0 or lower, and A laminated optical film characterized by the elastic modulus of the adhesive layer being 1× 10⁵ Pa or more and 3× 10⁶ Pa or less.
In Article 1, A laminated optical film in which the first optical film is a liquid crystal film or a phase difference film.
In Article 1 or Article 2, A laminated optical film having an adhesive layer thickness of 0.1 to 10 μm.
In any one of paragraphs 1 to 3, A laminated optical film having a second optical film further laminated on the side opposite to the side where the acrylic film of the first optical film is laminated, with an adhesive layer interposed therebetween.
In Article 4, A laminated optical film in which the second optical film is a liquid crystal film or a phase difference film.
In any one of paragraphs 1 to 5, The above adhesive composition contains polymerizable compound A, and The above polymerizable compound A is a urethane (meth)acrylate having a molecular weight of 5000 or more and having at least two polymerizable groups, and A laminated optical film in which, when the total amount of the polymerizable compound contained in the above adhesive composition is 100 parts by mass, the content of the polymerizable compound A is 4 parts by mass or more and 30 parts by mass or less.
In any one of paragraphs 1 to 6, The above adhesive composition contains polymerizable compound B, and The above-mentioned polymerizable compound B is a compound having at least two polymerizable groups, and A laminated optical film in which, when the total amount of the polymerizable compound contained in the adhesive composition is 100 parts by mass, the content of the polymerizable compound B is 0 parts by mass or more and 15 parts by mass or less.
In any one of paragraphs 1 to 7, The above adhesive composition contains polymerizable compound C, and The above-mentioned polymerizable compound C has a logPow representing the octanol/water partition coefficient of 1.0 or more and 8.0 or less, and A laminated optical film in which, when the total amount of the polymerizable compound contained in the above adhesive composition is 100 parts by mass, the content of the polymerizable compound C is 50 parts by mass or more and 95 parts by mass or less.
In any one of paragraphs 1 through 8, The above adhesive composition contains polymerizable compound D, and The above-mentioned polymerizable compound D is a compound having a refractive index of 1.5 or higher and 1.7 or lower, and A laminated optical film in which, when the total amount of the polymerizable compound contained in the above adhesive composition is 100 parts by mass, the content of the polymerizable compound D is 0 parts by mass or more and 95 parts by mass or less.
An image display device having at least one laminated optical film as described in claim 1.

Description

Laminated optical film and image display device The present invention relates to a laminated optical film in which at least an acrylic film and a first optical film are laminated with an adhesive layer interposed therebetween. The laminated optical film can form an image display device such as a mobile phone, a car navigation device, a PC monitor, or a television. Image display devices such as mobile phones, car navigation devices, PC monitors, and televisions are equipped with a laminated optical film in which multiple optical films are laminated with an adhesive layer or a pressure-sensitive adhesive layer interposed therebetween. As the optical film, a polarizer or a transparent resin film such as an acrylic film is used. Regarding acrylic films, since there are almost no functional groups on the film surface that can contribute to improving adhesion, there is concern that the adhesion between the acrylic film and other optical films may not be sufficient when they are used to form laminated optical films. In this regard, the following patent document 1 describes an optical film laminate formed by an active energy-curable adhesive, wherein the adhesive layer contains 2 to 35 parts by weight of a polymerizable monomer that dissolves the (meth)acrylic resin layer and 30 to 60 parts by weight of a polymerizable polyfunctional acrylate compound, based on the total amount of 100 parts by weight of the active energy-curable compound containing a polymerizable monomer that dissolves the (meth)acrylic resin layer and a polymerizable polyfunctional acrylate compound. FIG. 1 is an example of a cross-sectional schematic diagram of a laminated optical film according to one embodiment of the present invention. FIG. 1 shows an example of a cross-sectional schematic diagram of a laminated optical film according to an embodiment of the present invention. In this embodiment, the laminated optical film (10) has an acrylic film (1) and a first optical film (2) laminated with an adhesive layer (3) interposed therebetween, and the adhesive layer (3) is not interposed between the acrylic film (1) and the adhesive layer (3), and the acrylic film (1) and the adhesive layer (3) have a structure in which they are in direct contact. Details regarding the acrylic film (1), the first optical film (2), and the adhesive layer (3) will be explained separately. In this embodiment, the laminated optical film (10) has a triacetylcellulose film (6), which is a transparent protective film, further laminated on the opposite side of the surface where the first optical film (2) of the acrylic film (1) is laminated, with a water-based adhesive layer (7) interposed therebetween, and a second optical film (4) further laminated on the opposite side of the surface where the acrylic film (1) of the first optical film (2) is laminated, with a pressure-sensitive adhesive layer (5) interposed therebetween. Details regarding the pressure-sensitive adhesive layer (5) and the second optical film (4) will be explained separately. In this embodiment, the second optical film (4) is bonded to an image display device (not shown in FIG. 1) with a pressure-sensitive adhesive layer (8) interposed on the opposite side of the surface where the first optical film (2) is laminated. Each component will be explained below. Acrylic Film The acrylic film contains a (meth)acrylic resin. The (meth)acrylic resin film is obtained, for example, by extrusion molding a molding material containing a resin component comprising a (meth)acrylic resin as a main component. The (meth)acrylic resin has a Tg (glass transition temperature) of preferably 70°C or higher, more preferably 110°C or higher, even more preferably 115°C or higher, and particularly preferably 120°C or higher. The (meth)acrylic resin film can have excellent durability by including a (meth)acrylic resin having a Tg (glass transition temperature) of 70°C or higher as a main component. The upper limit of the Tg of the (meth)acrylic resin is not particularly limited, but is preferably 170°C or lower from the perspective of moldability, etc. Any suitable (meth)acrylic resin may be used as the above (meth)acrylic resin. Examples include poly(meth)acrylic acid esters such as polymethyl methacrylate, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-(meth)acrylic acid ester copolymers, methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymers, methyl methacrylate-styrene copolymers (MS resin, etc.), and polymers having alicyclic hydrocarbon groups (e.g., methyl methacrylate-methacrylic acid cyclohexyl copolymers, methyl methacrylate-(meth)acrylic acid norbornyl copolymers, etc.). Preferably, poly(meth)acrylic acid C1-6 alkyls such as poly(meth)acrylate may be used. More preferably, a methyl methacrylate-based resin having methyl methacrylate as the main component (50 to 100 weight%, preferably 70 to 100 weight%) can be cited. In the present invention, as the (meth)acrylic resin having high h