PET Protective Film Polarizing Plate Adhesion and Optical Control
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Solution Overview
Problem
Polarizing plates using polyethylene terephthalate films suffer from high in-plane retardation values leading to optical interference issues, poor adhesion with polyvinyl alcohol-based adhesives, and low moisture permeability, which result in durability and optical property degradation, especially under high-speed lamination processes.
Innovation Solution
A polarizing plate design incorporating a water-based adhesive layer with a glyoxalate crosslinking agent and a primer layer composed of polyester and acryl-based compounds, applied to a stretched polyethylene terephthalate film, enhancing adhesion and optical properties while maintaining low production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyethylene terephthalate film is used as protection film to reduce manufacturing costs, then cost is reduced and durability is improved, but in-plane retardation value becomes large causing optical interference and poor visual sense
Solution Approach 1:
The patent applies parameter changes by stretching the polyethylene terephthalate film to control its in-plane retardation value. Through controlled stretching, the film's optical properties are modified to reduce optical interference while maintaining the cost and durability advantages of PET material.
Solution Approach 2:
The patent creates a composite structure by combining stretched polyethylene terephthalate film with a primer layer and adhesive layer. This composite approach allows the PET film to provide cost and durability benefits while the primer layer compensates for optical interference issues through controlled optical property modification.
2Strength
If polyethylene terephthalate film is attached to polarizer with water-based adhesive, then adhesion force is low and stripping occurs, but using traditional adhesive formulation maintains simplicity
Solution Approach 1:
The patent introduces a primer layer as an intermediary between the polyethylene terephthalate film and the water-based adhesive. This primer layer serves as a mediator that enhances adhesion force by creating a better bonding interface, allowing strong adhesion without complicating the adhesive formulation itself.
Solution Approach 2:
The patent applies preliminary action by forming a primer layer on the PET film before applying the water-based adhesive. This preliminary step prepares the surface to improve adhesion, enabling strong bonding while keeping the adhesive formulation simple and water-based.
3Reliability
If polyethylene terephthalate film is used with low moisture permeability, then durability is improved, but drying becomes difficult when water-based adhesive is used
Solution Approach 1:
The primer layer acts as an intermediary that facilitates moisture transfer between the low-moisture-permeability PET film and the water-based adhesive. This mediator enables proper drying of the adhesive while maintaining the durability benefits of the PET film's low moisture permeability.
4Productivity
If high-speed lamination process is used to improve productivity, then manufacturing speed is improved, but orthogonal optical properties are severely degraded
Solution Approach 1:
The patent applies preliminary action by pre-forming the primer layer on the PET film before the high-speed lamination process. This preliminary preparation ensures that when the adhesive is applied quickly, the optical properties are already optimized, allowing high productivity while maintaining orthogonal optical properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves adhesion force by 800% and maintains excellent orthogonal optical properties, reducing optical interference and durability issues, even under high-speed lamination, with the polyethylene terephthalate film serving as an effective protection layer.
Implementation Method 1
a water-based adhesive layer, a primer layer, and a polyethylene terephthalate protection film sequentially provided on at least one surface of a polarizer, in which the water-based adhesive layer is formed by using a water-based adhesive including a polyvinyl alcohol-based resin and a glyoxalate crosslinking agent
Implementation Method 2
the primer layer is formed by using a primer composition including a polyester-based compound and an acryl-based compound
Data Source
AI summary
The present invention relates to a polarizing plate including a polyethylene terephthalate film and having an excellent optical property, and a method for manufacturing the same, and the polarizing plate of the present invention includes: a water-based adhesive layer, a primer layer, and a polyethylene terephthalate protection film sequentially provided on at least one surface of a polarizer, in which the water-based adhesive layer is formed by using a water-based adhesive including a polyvinyl alcohol-based resin and a glyoxalate crosslinking agent at a weight ratio of 100:5 to 100:50, and the primer layer is formed by using a primer composition including a polyester-based compound and an acryl-based compound.