Fumaric Acid Ester Resin Film With High Tβ and Dimensional Stability
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Solution Overview
Problem
Existing fumaric acid ester resins used in retardation films lack sufficient heat resistance, leading to dimensional instability in high-temperature environments due to low β relaxation temperature (Tβ) of the resin side chain movement.
Innovation Solution
A novel fumaric acid ester monomer with a specific structure, incorporating cyclohexane rings in the side chains, which allows for high β relaxation temperature (Tβ) and high molecular weight resin formation, resulting in a film with improved thermal stability and reduced linear expansion coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional fumaric acid ester resins are used in retardation films, then the films can provide negative birefringence and retardation characteristics, but the films exhibit low heat resistance and dimensional instability in high-temperature environments due to low β relaxation temperature (Tβ)
Solution Approach 1:
The invention changes the chemical structure parameters of the fumaric acid ester resin by introducing specific side chain structures (cyclic structures such as cyclohexyl groups) to increase the β relaxation temperature (Tβ) from conventional low values to 100°C or higher, thereby improving heat resistance and dimensional stability simultaneously
Solution Approach 2:
The invention creates a composite resin system by combining fumaric acid ester main chains with specific cyclic side chain structures (cyclohexyl, tetrahydrofurfuryl groups), forming a composite material that achieves both the required negative birefringence and high heat resistance properties
2Stability of the object's composition
If acrylic resins are used to achieve negative birefringence, then the birefringence requirement is met, but the retardation developability is insufficient and characteristics as a retardation film are not sufficient
Solution Approach 1:
The invention changes the molecular structure parameters by selecting specific side chain structures (cyclic groups with 3-8 carbon atoms) that simultaneously provide negative birefringence and enable sufficient retardation developability, achieving both optical properties required for retardation films
3Stability of the object's composition
If polystyrene is used to achieve negative birefringence, then the birefringence requirement is met, but the heat resistance is low and the photoelasticity is large causing retardation to change with slight stress
Solution Approach 1:
The invention changes the chemical structure by replacing the polystyrene backbone with a fumaric acid ester backbone and introducing specific cyclic side chains, which increases the glass transition temperature and reduces photoelasticity while maintaining negative birefringence
Solution Approach 2:
The invention creates a composite structure combining the rigid fumaric acid ester main chain with cyclic side groups, forming a material that exhibits both negative birefringence and improved thermal stability compared to conventional polystyrene
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 novel fumaric acid ester monomer and resin produce a film with high Tβ and low linear expansion coefficient, enhancing thermal resistance and dimensional stability, making it suitable for high-temperature applications.
Implementation Method 1
a resin includes a residue unit represented by structural formula (2)
Implementation Method 2
Fumaric acid ester resins have a β relaxation temperature (T β ) corresponding to the side chain movement of the resin
Implementation Method 3
The optical anisotropy of the polymer film molecularly oriented by stretching, casting by a coater or the like can be represented by the indicatrix defining the refractive index in the fast axis direction (direction of smallest refractive index) in the film plane as nx, and the refractive index in a film in-plane direction (slow axis) orthogonal to this as ny
Data Source
AI summary
Provided are: a novel fumaric acid ester monomer that yields a resin having high Tβ; a resin; and a film containing the same. This fumaric acid ester monomer is represented by formula (1). In the formula, R1 represents a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 5 carbon atoms, and R2 represents a linear alkyl group having 1 to 4 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.