Polycarbonate Light-Diffusing Plate Resin Composition
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Solution Overview
Problem
Light diffusing plates made from polycarbonate resin used in LCDs face issues with light degradation and color tone deterioration due to the addition of ultraviolet absorbers and fluidizers, especially in injection molding, which affects their luminance and stability.
Innovation Solution
A polycarbonate-base light-diffusing resin composition containing specific additives such as light diffusing agents, light resistant agents, ester compounds, organopolysiloxane, and acrylic thermoplastic resin, optimized to maintain initial color tone and enhance light resistance and luminance, regardless of molding method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultraviolet absorbers and advanced fluidizers are added to enhance light resistance and fluidity for injection molding, then light resistance and moldability are improved, but color tone deterioration (increase in YI and chromaticity) occurs
Solution Approach 1:
The patent changes the chemical parameters by selecting specific types of ultraviolet absorbers (malonate-base, oxalylanilide-base, benzotriazole-base compounds) and controlling their concentration within 0.05-10 parts by mass per 100 parts of polycarbonate resin. This parameter optimization ensures sufficient light resistance while minimizing coloration. The patent also controls the ester compound content at 0.01-1 part by mass to further suppress color tone deterioration during high-shear rate injection molding
Solution Approach 2:
The patent creates a composite resin composition by combining polycarbonate resin with multiple functional additives: light diffusing agents (0.01-10 parts by mass), light resistant agents (specific types of ultraviolet absorbers), and ester compounds (0.01-1 part by mass). This composite formulation achieves synergistic effects where each component contributes to overall performance while minimizing adverse effects on color stability
2Reliability
If the concentration of ultraviolet absorbers is raised to enhance light resistance in injection-molded single-layer plates, then light resistance is improved, but color tone deterioration (increase in YI) occurs
Solution Approach 1:
The patent optimizes the concentration parameter of ultraviolet absorbers to a specific range (0.05-10 parts by mass per 100 parts of polycarbonate resin) rather than simply increasing it. This controlled parameter change ensures adequate light resistance while preventing excessive coloration. The patent also introduces ester compounds at 0.01-1 part by mass as a complementary parameter adjustment to further suppress color tone deterioration
3Productivity
If advanced fluidizers such as styrene-acrylic copolymer are added to improve fluidity for large-size injection molding, then moldability is improved, but color tone deterioration (increase in chromaticity) occurs
Solution Approach 1:
The patent addresses fluidity requirements by controlling the ester compound content (0.01-1 part by mass) and optimizing the base polycarbonate resin properties rather than relying heavily on advanced fluidizers. This parameter optimization approach improves moldability for large-size injection molding while minimizing coloration. The patent balances fluidity enhancement with color stability through controlled additive concentrations
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 composition achieves favorable light diffusibility, high luminance, and improved light resistance while maintaining initial color tone, making it suitable for large-sized LCD applications and high-shear rate injection molding.
Implementation Method 1
light diffusing plates for scattering light from backlights
Implementation Method 2
PC resin indispensably needs to be added with light resistant agent(s)
Data Source
AI summary
A polycarbonate-base light-diffusing resin composition contains: (A) 100 parts by mass of an aromatic polycarbonate resin; (B) 0.01 to 10 parts by mass of a light diffusing agent; (C) 0.05 to 5 parts by mass of a light resistant agent, the light resistant agent being one or more light resistant agent selected from a malonate-base compound, an oxalylanilide-base compound, a benzotriazole-base compound and an acrylic resin having a side chain of a benzotriazole-base skeleton; and 0.01 to 1 parts by mass of an ester compound of fatty acid and multivalent alcohol. By molding the composition by injection molding or the like, a light diffusing plate is obtained.