Acrylic Resin Dope Composition for Polarizing Plate Protective Film

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing dope compositions used in the solution film formation method for polarizing plate protective films have low viscosity, leading to issues like streaks during production, low breaking elongation, and slow drying times, which affect the quality and productivity of the films.

Innovation Solution

A dope composition with an acrylic resin having a weight average molecular weight of greater than or equal to 250,000 and an additive with a weight average molecular weight of less than 50,000, along with specific monomer units and additives, is used to increase viscosity, enhance breaking elongation, and accelerate drying.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If acrylic resin with low molecular weight (80,000 to 150,000) is used in solution film formation, then the dope composition has low viscosity and is easy to process, but the film has low breaking elongation,容易产生 streaks, and cracks easily during stretching

Engineering Contradiction:

Improveease of film formationVSAvoidbreaking elongation

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent changes the molecular weight parameter of the acrylic resin from the conventional 80,000-150,000 to 250,000 or more, fundamentally altering the dope composition properties to achieve both high viscosity for streak prevention and high breaking elongation for crack resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system by combining high molecular weight acrylic resin (≥250,000) with specific additives and solvents, achieving a balance between processing ease and mechanical strength that neither component could achieve alone

Inventive Principle:

Principle #40Composite materials

2Strength

If acrylic resin with high molecular weight (>150,000) is used, then the film has high breaking elongation and resistance to cracking, but the dope composition has high viscosity making film formation difficult

Engineering Contradiction:

Improvebreaking elongationVSAvoidease of film formation

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent optimizes the molecular weight parameter to be ≥250,000 and controls the concentration of the acrylic resin in the dope composition to 5-30% by mass, achieving sufficient viscosity for crack resistance while maintaining processability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces solvents and additives as intermediaries to reduce the viscosity of the high molecular weight acrylic resin dope, enabling easy film formation while preserving the high breaking elongation properties of the polymer

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the thickness of cellulose triacetate film is reduced to decrease moisture permeability, then low moisture permeability is achieved, but optical influence increases

Engineering Contradiction:

Improvemoisture permeabilityVSAvoidoptical quality

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent uses PMMA as a replacement material for cellulose triacetate, creating a protective film that inherently provides low moisture permeability without requiring extreme thinness, thus avoiding optical quality degradation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the material composition from cellulose triacetate to PMMA, fundamentally altering the moisture barrier properties while maintaining optical clarity, allowing the film to provide both protection and optical quality

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If acrylic resin with low molecular weight is used, then the dope composition has low viscosity for easy processing, but the drying time of the casting film is prolonged due to small diffusion coefficient

Engineering Contradiction:

Improveease of processingVSAvoiddrying time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent optimizes the molecular weight parameter to ≥250,000 and controls the dope composition concentration to 5-30% by mass, achieving a balance where the dope has sufficient viscosity for streak-free casting while maintaining adequate solvent diffusion for reasonable drying times

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10501593B2Dope composition, polarizing plate protective film, polarizing plate protective film manufacturing method, polarizing plate, and liquid crystal display device

Publication Date: 2019.12.10 FUJIFILM CORP

AI summary

A dope composition containing an acrylic resin having a weight average molecular weight of greater than or equal to 250,000; and an additive having a weight average molecular weight of less than 50,000, in which the acrylic resin includes a methyl methacrylate unit (a), and a mass fraction of an alkyl (meth)acrylate unit (b) other than methyl methacrylate is less than 5 mass %, has excellent manufacturing aptitude from the viewpoint of having a high drying speed and large breaking elongation at a time point of forming an un-stretched film, and enabling a crack at the time of being stretched to be suppressed, has a low haze value and an excellent surface shape at the time of preparing a polarizing plate protective film, and has excellent heat resistance; a polarizing plate protective film; a polarizing plate protective film manufacturing method; a polarizing plate; and a liquid crystal display device.