Polarizing plate and laminated optical member using photocurable adhesive

Abstract

Provided is a polarizing plate configured from a polyvinyl alcohol-based polarizer and a transparent protective film pasted onto the polarizer with an adhesive therebetween, wherein the adhesive contains 100 parts by weight of a photo cation curable component (A) and 1-10 parts by weight of a photo cation polymerization initiator (B), and the photo cation curable component (A) is formed from a photocurable adhesive containing the following (A1)-(A3) at the following quantities relative to the total quantity thereof: 30-85 wt% of an alicyclic diepoxy compound (A1) represented by formula (I); 1-69 wt% of a diglycidyl compound (A2) represented by formula (II), Z being a branch structure; and 1-69 wt% of a monofunctional epoxy compound (A3) represented by formula (III). The weight reduction of the protective film when the protective film is immersed at 23°C for two days in the photocurable adhesive is 0-30 wt%.

Description

technical field [0001] The present invention relates to a polarizing plate in which a protective film made of a transparent resin is bonded to a polarizer made of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented via a photocurable adhesive, And a laminated optical member obtained by laminating another optical layer such as a retardation film on the polarizing plate. Background technique [0002] A polarizing plate can be used as one of optical components constituting a liquid crystal display device. Generally, a polarizing plate has a structure in which protective films are laminated on both surfaces of a polarizer, and is incorporated into a liquid crystal display device. It is also known that a protective film is provided only on one side of a polarizer, but in many cases, a layer having other optical functions, not just a protective film but also a protective film, is attached to the other side. In addition, as a method for producing...

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Problems solved by technology

[0004] Triacetyl cellulose has the following excellent advantages as a protective film: excellent transparency, easy to form various surface treatment layers or optical functional layers, high moisture permeability, and drying after bonding on the polarizer using the above-mentioned water-based adhesive. It went smoothly, but on the contrary, there were the following problems: due to the high moisture permeability, the polarizer laminated as a protective film was prone to deterioration under conditions of humidity and heat, such as a temperature of 70°C and a relative humidity of 90%.

[0005] When laminating a protective film made of a resin with low moisture permeability to a polyvinyl alcohol-based polarizer, if the polyvinyl alcohol-based resin commonly used in pasting polyvinyl alcohol-based polarizers and triacetyl cellulose films When an aqueous solution is used as the adhesive, there is a problem that the adhesive strength is insufficient, or the appearance of the obtained polarizer is poor.

This is because a resin film with low moisture permeability is generally hydrophobic, or the water used as a solvent cannot be sufficiently dried due to low moisture permeability, etc.

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