Phosphorescent Polycarbonate Composition for Clear Red Light
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Solution Overview
Problem
Existing polycarbonate resin compositions with phosphorescent materials face issues such as yellowing, darkening, and inability to emit clear red light, and are limited to single-color light emission, lacking blends of multiple phosphorescent materials to achieve desired color tones like white.
Innovation Solution
A phosphorescent polycarbonate resin composition is developed, incorporating a red light-emitting phosphorescent material with a stabilizer, and optionally blue and green materials, achieving an L* value of 65 or more, and containing a phosphate stabilizer to prevent resin degradation, enabling clear red or white light emission during light blockage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a red phosphorescent pigment is blended with polycarbonate resin, then red light emission is achieved, but yellowing or darkening occurs and clear red light emission is not achieved
Solution Approach 1:
A phosphate stabilizer is introduced as an intermediary substance between the red phosphorescent pigment and the polycarbonate resin. This stabilizer prevents direct harmful interactions that cause yellowing and darkening, while allowing the phosphorescent pigment to maintain its red light emission properties. The stabilizer acts as a protective mediator during the kneading and molding processes.
Solution Approach 2:
The invention creates a composite material system consisting of polycarbonate resin, red phosphorescent pigment, and phosphate stabilizer. This composite formulation allows the combination of materials with different functions: the resin provides structural base, the pigment provides red light emission, and the stabilizer prevents degradation, achieving clear red light emission without yellowing or darkening.
2Illumination intensity
If existing phosphorescent pigments are used, then light emission in green, blue-green, blue, or purple is achieved, but red light emission is not achieved
Solution Approach 1:
The invention changes the key parameter of the phosphorescent pigment from traditional green, blue-green, blue, or purple emitting pigments to a specific red phosphorescent pigment. This parameter change in emission wavelength is made possible by introducing the phosphate stabilizer, which enables the red pigment to function properly in the polycarbonate resin system without causing yellowing or darkening.
3Ease of manufacture
If phosphorescent polycarbonate resin composition is molded, then phosphorescent light-emitting members are produced, but high-temperature retention causes yellowing or darkening
Solution Approach 1:
The phosphate stabilizer is incorporated into the resin composition before the molding process. This beforehand cushioning provides protection against the high-temperature conditions during molding and retention, preventing yellowing and darkening from occurring in the first place rather than attempting to correct them after they occur.
4Ease of operation
If only single phosphorescent material is used, then single-color light emission is achieved, but desired color tones like white cannot be realized
Solution Approach 1:
The invention merges multiple phosphorescent materials with different emission characteristics into a single resin composition. By combining these materials and using the phosphate stabilizer to prevent interactions that would cause yellowing, the system achieves versatile color tones including white light emission, while maintaining ease of operation through a unified molding process.
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 provides stable, clear red or white light emission without yellowing or darkening, suitable for various applications including electronic signage and automotive components.
Implementation Method 1
A phosphorescent material is, when irradiated with light such as ultraviolet light or visible light contained in sunlight, artificial light, or the like, absorbs and stores the light and, even after light irradiation is stopped, that is, even in the dark, continues to emit light in the form of radiation for a predetermined time period.
Data Source
AI summary
A phosphorescent polycarbonate resin composition comprising, with respect to 100 parts by mass of a polycarbonate resin (A): 0.8 to 20 parts by mass of a red light-emitting phosphorescent material (B1) as a phosphorescent material (B), wherein an L* value measured in accordance with a following method (X) is 65 or more, the method (X) including: under conditions of a cylinder temperature of 300°C, a mold temperature of 120°C, and a molding cycle of 45 seconds, measuring, with a color-difference meter, the L* of a 3 mm-thick portion of a specimen (in a form of a three-stage plate having a width of 50 mm, a length of 90 mm, and thicknesses of 1 mm, 2 mm, and 3 mm) obtained by injection molding of the phosphorescent polycarbonate resin composition, under following conditions based on JIS Z8772: Reflection measurement: D65 light source, 10-degree field of view Measurement port: 30 φ Specimen material holder: White