Methods for producing polarizing laminate film and polarizing plate

Abstract

A method for producing a polarizing laminate film including a base film and a polarizer layer formed on one surface of the base film involves, in the following order: a resin film laminating step of laminating a resin film made of a polyvinyl alcohol resin and having a thickness of 50 [mu]m or less onto one surface of a base film, to thereby obtain a laminate film; a stretching step of uniaxially stretching the laminate film; and a dyeing step of dyeing the resin film of the uniaxially stretched laminate film with a dichroic dye, to thereby form a polarizer layer. The present invention can provide a method for producing a polarizing laminate film having a thin polarizer layer without giving rise to the problem that the ends of the base film are folded inside.

Description

technical field [0001] The present invention relates to a method for manufacturing a polarizing laminated film and a polarizing plate. Background technique [0002] A polarizing plate is widely used as a polarized light supply element and the like in display devices such as liquid crystal display devices. As the polarizing plate, a polarizing plate in which a polarizer layer made of a polyvinyl alcohol-based resin and a protective film such as triacetyl cellulose are laminated has been conventionally used. The polarizer layer (polarizing film) is not only required to have high optical performance, but also has been required to be thinner and lighter in recent years with the development of liquid crystal display devices in mobile devices such as notebook PCs and mobile phones. [0003] As an example of a method for producing a polarizing plate, a method is known in which a polarizing film is produced by stretching a film made of a polyvinyl alcohol-based resin alone, or perf...

AI Technical Summary

Problems solved by technology

[0006] However, in the method of manufacturing a polarizing film by stretching, dyeing, and cross-linking a film made of a polyvinyl alcohol-based resin, it is difficult to handle a thin film of 50 μm or less because it is prone to breakage and wrinkles. Therefore, it is difficult to realize the thinning of the polarizing film

[0007] In the method of applying a solution containing a polyvinyl alcohol-based resin on the surface of a base film to form a resin layer, the resin layer tends to shrink due to drying shrinkage of the solution containing a polyvinyl alcohol-based resin, and as a result, bases may sometimes occur. The phenomenon that both ends of the material film are warped toward the resin layer side. If the base film with the resin layer is kept flowing continuously in this state, it will cause the end of the base film to bend in the drying furnace or at the outlet of the drying furnace. bad condition

[0008] In the method of producing a laminated film by co-extruding a protective film resin and a polyvinyl alcohol-based resin, the polyvinyl alcohol-based resin is usually melted together with a solvent and extruded. Defective conditions that cause the edge of the base film to bend

Images