KR-20260064627-A - POLARIZING PLATE AND PHOTOCURABLE ADHESIVES

Abstract

The present invention aims to provide a polarizing plate in which the polarizing film is resistant to discoloration even under high humidity environments. The polarizing plate (1) of the present invention comprises a first (meth)acrylic resin film (21), a first adhesive layer (31), a polyvinyl alcohol-based polarizing film (10), a second adhesive layer (32), and a second (meth)acrylic resin film (22) laminated in this order, wherein the first adhesive layer (31) and the second adhesive layer (32) contain a photocation-curable component (A) and a photocation polymerization initiator (B) in an amount of 1 to 10 parts by weight per 100 parts by weight of the photocation-curable component (A), and the photocation-curable component (A) in an amount of 20 to 50 parts by weight of an alicyclic epoxy compound (A-1), 20 to 55 parts by weight of an aliphatic diglycidyl compound (A-2), 5 to 15 parts by weight of a polymer (A-3) comprising a constituent unit derived from a monomer having a substituent such as an epoxy group, and an oxetane compound (A-4). It is a cured product of a photocurable adhesive containing 5 to 25 parts by weight.

Inventors

• 편 보람
• 이구치 마리
• 혼마 에리
• 마츠도 가즈히코
• 이타노 가즈유키

Assignees

• 스미또모 가가꾸 가부시키가이샤
• 가부시키가이샤 아데카

Dates

Publication Date

20260507

Application Date

20251030

Priority Date

20241031

Claims (3)

1. A polarizing plate in which a first (meth)acrylic resin film, a first adhesive layer, a polyvinyl alcohol-based polarizing film, a second adhesive layer, and a second (meth)acrylic resin film are laminated in this order, The first adhesive layer and the second adhesive layer are A photocation curable component (A) and, 1 to 10 parts by weight of a photocationic polymerization initiator (B) per 100 parts by weight of the above photocationic curable component (A) Contains, The above photocation-curable component (A) comprises an alicyclic epoxy compound (A-1), an aliphatic diglycidyl compound (A-2), a polymer (A-3) comprising a constituent unit derived from a monomer having one or more substituents selected from an epoxy group, an oxetanyl group and a (meth)acryloyl group, and an oxetane compound (A-4). Of the above 100 parts by weight of the photocation curable component (A) The content of the above-mentioned cycloaliphatic epoxy compound (A-1) is 20 to 50 parts by weight, and The content of the above-mentioned aliphatic diglycidyl compound (A-2) is 20 to 55 parts by weight, and The content of the above polymer (A-3) is 5 to 15 parts by weight, and The above oxetane compound (A-4) has a content of 5 to 25 parts by weight, cured product of a photocurable adhesive Polarizer.
2. A polarizing plate according to claim 1, wherein the content of an aromatic epoxy compound (A-5) in 100 parts by weight of the photocation-curable component (A) is 5 parts by weight or less.
3. A photocation curable component (A) and, 1 to 10 parts by weight of a photocationic polymerization initiator (B) per 100 parts by weight of the above photocationic curable component (A) Contains, The above photocation-curable component (A) comprises an alicyclic epoxy compound (A-1), an aliphatic diglycidyl compound (A-2), a polymer (A-3) comprising a constituent unit derived from a monomer having one or more substituents selected from an epoxy group, an oxetanyl group and a (meth)acryloyl group, and an oxetane compound (A-4). Of the above 100 parts by weight of the photocation curable component (A) The content of the above-mentioned cycloaliphatic epoxy compound (A-1) is 20 to 50 parts by weight, and The content of the above-mentioned aliphatic diglycidyl compound (A-2) is 20 to 55 parts by weight, and The content of the above polymer (A-3) is 5 to 15 parts by weight, and The above oxetane compound (A-4) has a content of 5 to 25 parts by weight, Photocurable adhesive.

Description

Polarizing Plate and Photocurable Adhesives The present invention relates to a polarizing plate. It is known that a polarizing plate used for bonding to an image display device, such as a liquid crystal display device, has a configuration in which protective films are laminated on both sides of a polarizing film. As the polarizing film, a polyvinyl alcohol-based polarizing film in which iodine is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film is known, and as the protective film, a (meth)acrylic-based resin film is known. An adhesive is used to laminate the protective film to the polarizing film, and as the adhesive, a photocurable adhesive is known that contains a photocation-curable component and a photocation polymerization initiator, and cures and exhibits adhesive strength when irradiated with light. For example, Patent Document 1 discloses a photocurable adhesive as an adhesive for laminating a polarizing film and a (meth)acrylic-based resin film, which contains a polymer comprising an aliphatic diglycidyl compound and a constituent unit derived from a monomer containing an epoxy group as the photocation-curable component. FIG. 1 is a cross-sectional view schematically showing an example of a polarizing plate of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a polarizing plate of the present invention bonded to an image display element. Figure 3 is a diagram schematically illustrating the discoloration of the polarizer in Evaluation 1 and Evaluation 2. The present invention will be described in detail below by presenting embodiments. Furthermore, the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made within the scope that does not deviate from the spirit of the present invention. [Composition of polarizers] FIG. 1 is a schematic cross-sectional view showing an example of a polarizing plate (1) according to the present invention. As shown in FIG. 1, the polarizing plate (1) of the present invention comprises a first (meth)acrylic resin film (21), a first adhesive layer (31), a polyvinyl alcohol-based polarizing film (10), a second adhesive layer (32), and a second (meth)acrylic resin film (22) in this order. Typically, the first (meth)acrylic resin film (21) is laminated in contact with the surface of the first adhesive layer (31), and the first adhesive layer (31) is laminated in contact with the surface of the polyvinyl alcohol-based polarizing film (10). Also, typically, the second (meth)acrylic resin film (22) is laminated in contact with the surface of the second adhesive layer (32), and the second adhesive layer (32) is laminated in contact with the surface of the polyvinyl alcohol-based polarizing film (10). The first (meth)acrylic resin film (21) and the second (meth)acrylic resin film (22) may each be a phase difference film having a phase difference, a reflective film that reflects incident light, a light diffusion film that transmits incident light while diffusing it, or an ultraviolet absorbing film containing an ultraviolet absorber. In the polarizing plate (1) of the present invention, another layer may be laminated on the opposite side of the first adhesive layer (31) and the second adhesive layer (32) of the first (meth)acrylic resin film (21) and the second (meth)acrylic resin film (22). Examples of other layers include a phase difference layer, a reflection layer, a light diffusion layer, a light collecting plate, a brightness enhancement film, an adhesive layer, an adhesive layer, etc. Two or more other layers may be laminated in the polarizing plate (1) of the present invention. [1st (Met)Acrylic Resin Film and 2nd (Met)Acrylic Resin Film] The first (meth)acrylic resin film (21) and the second (meth)acrylic resin film (22) are films of (meth)acrylic resin. The (meth)acrylic resin constituting the first (meth)acrylic resin film (21) and the second (meth)acrylic resin film (22) is not particularly limited, but is generally a polymer having methacrylic acid ester as the main monomer, and is preferably a copolymer in which a small amount of other comonomer component is copolymerized therein. This copolymer can typically be obtained by polymerizing a monofunctional monomer composition containing (meth)acrylic acid esters such as methyl methacrylate and methyl acrylate, together with other comonomer components in the presence of a radical polymerization initiator and a chain transfer agent. Examples of (meth)acrylic acid esters include, for instance, methacrylic acid esters other than methyl methacrylate, such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate; acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl