Ester Plasticizer for Cellulose Ester Film Melt-Casting
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Solution Overview
Problem
The production of cellulose ester films using the solution-casting method is limited by high environmental load due to the use of halogen-based solvents, and melt-casting faces challenges with film flatness and plasticizer bleeding due to high viscosity and glass transition point of cellulose ester, as well as instability of phosphoric acid plasticizers.
Innovation Solution
The development of ester compounds formed by condensing aromatic carboxylic acids with polyhydric alcohols, which act as plasticizers, reducing viscosity and bleeding, and are chemically stable, allowing for high flatness and compatibility with cellulose ester films produced by melt-casting without halogen-based solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solution-casting method is used to produce cellulose ester film, then film flatness and image quality are improved, but environmental load increases due to use of halogen-based solvents
Solution Approach 1:
The invention changes the physical state parameter of the cellulose ester from dissolved state (solution-casting) to melted state (melt-casting). By heating the cellulose ester to its melting point and above, the process eliminates the need for halogen-based solvents while maintaining film flatness through controlled cooling and solidification processes.
Solution Approach 2:
The invention extracts and removes the harmful halogen-based solvents from the film production process. By using melt-casting instead of solution-casting, the harmful solvent component is completely eliminated, replacing it with a thermal processing approach that achieves the same film flatness without environmental damage.
2Object-affected harmful factors
If melt-casting method is used to produce cellulose ester film, then environmental load is reduced by eliminating solvent use, but film flatness deteriorates due to high viscosity and rapid solidification
Solution Approach 1:
The invention applies preliminary action by adding plasticizers to the cellulose ester before melting and casting. The plasticizers are incorporated in advance to reduce the viscosity of the melted cellulose ester, allowing it to flow and level properly during casting, thereby achieving flat film surfaces despite the inherently high viscosity of cellulose ester.
Solution Approach 2:
The invention changes the temperature parameter during the casting process by controlling the cooling rate and maintaining the melt above the glass transition temperature for sufficient time to allow leveling. This temporal control of temperature ensures the material remains in a flowable state long enough to achieve flatness before solidification occurs.
3Ease of manufacture
If phosphoric acid plasticizers are used in melt-casting, then viscosity is reduced enabling film formation, but chemical stability deteriorates causing film degradation and staining
Solution Approach 1:
The invention replaces unstable phosphoric acid plasticizers with stable polyhydric alcohol carboxylic acid esters. These new plasticizers provide the necessary viscosity reduction but do not undergo decomposition reactions, thereby eliminating the generation of degradation-causing substances while maintaining ease of manufacture.
Solution Approach 2:
The invention converts the potential harm of phosphoric acid plasticizer decomposition into a benefit by selecting plasticizers that do not decompose. The polyhydric alcohol carboxylic acid esters provide the desired viscosity reduction without the harmful side effect of generating phosphoric acid, thereby turning a problematic process into a stable, reliable manufacturing method.
4Stability of the object's composition
If polyhydric alcohol-carboxylic acid plasticizers are used, then chemical stability is improved, but water vapor permeability reduction effect is insufficient
Solution Approach 1:
The invention uses composite plasticizer systems combining polyhydric alcohol carboxylic acid esters with specific structural features (aromatic rings, cyclic structures). These composite molecular structures provide both chemical stability and enhanced water vapor permeability reduction effects, as the aromatic and cyclic components contribute to tighter packing and reduced permeability while the polyhydric alcohol backbone maintains compatibility and stability.
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 use of these ester compounds enables the production of cellulose ester films with improved optical characteristics, dimensional stability, and flatness, suitable for polarizing plates and liquid crystal displays, while reducing environmental impact by minimizing solvent use.
Implementation Method 1
addition of plasticizers is effective to lower the melt viscosity and glass transition point of organic polymers such as cellulose ester
Implementation Method 2
addition of plasticizers is effective to lower the melt viscosity and glass transition point of organic polymers such as cellulose ester
Implementation Method 3
when cellulose ester is melted, extruded from a die and cast onto a cooling drum or belt
Implementation Method 4
after extrusion, solidification occurs in a relatively short time
Data Source
AI summary
A plasticizer comprising an ester compound produced by a condensation reaction of an organic acid represented by Formula (1) with a polyhydric alcohol having at least 3 hydroxyl groups in the molecule,