Infrared-Transmitting Polyester Resin for Lamp Parts
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Solution Overview
Problem
Existing polyester resin compositions for lamp parts face challenges in achieving infrared light-transmitting properties, heat resistance, and low gas emission while maintaining a black color, as they tend to suffer from temperature rises and surface melting due to sunlight condensation, and previous solutions either compromise on heat deflection temperature or exhibit poor infrared light transmittance.
Innovation Solution
A polyester resin composition comprising a blend of polybutylene terephthalate and polyethylene terephthalate resins, an inorganic filler with a particle size of 3 μm or less, a polyfunctional glycidyl group-containing styrene polymer, and an infrared light-transmitting black dye, which together provide a balance of infrared light transmittance, heat resistance, and low gas emission, ensuring the composition's suitability for black-colored design parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If noncrystalline resin is added to enhance infrared light transmittance, then infrared light transmittance is improved, but heat deflection temperature significantly lowers
Solution Approach 1:
The patent uses a composite resin system combining polybutylene terephthalate (PBT) as the base crystalline resin with specific noncrystalline resins (polycarbonate, polyethylene terephthalate, or polytrimethylene terephthalate) in controlled ratios. This composite approach allows the crystalline PBT to maintain high heat deflection temperature while the noncrystalline components enhance infrared light transmittance, resolving the contradiction between these two properties.
Solution Approach 2:
The patent precisely controls the composition ratios and molecular weight parameters of the resin components. By adjusting the ratio of PBT to noncrystalline resin (specifically using polycarbonate, PET, or PTT in defined proportions) and controlling the intrinsic viscosity ranges, the patent optimizes both infrared light transmittance and heat deflection temperature, transforming the trade-off into a balanced performance through parameter optimization.
2Shape
If carbon black is used to achieve black color, then blackness is improved, but temperature rise due to infrared light absorption increases
Solution Approach 1:
The patent replaces carbon black with an infrared light-transmitting black dye that selectively absorbs visible light to provide black color while transmitting infrared light. This color substitution strategy maintains the aesthetic black appearance required for lamp parts while eliminating the harmful infrared absorption and temperature rise associated with carbon black.
Solution Approach 2:
The patent substitutes a traditional, well-known material (carbon black) with a specialized alternative (infrared light-transmitting black dye). While the dye is a more specialized material, it provides superior performance by transmitting infrared light, effectively replacing the problematic carbon black in applications where infrared transmission is critical.
3Temperature
If pigment mixture is used to achieve black color without carbon black, then temperature rise is reduced, but the effect is small and infrared light transmittance is insufficient
Solution Approach 1:
The patent moves beyond simple pigment mixing to using a specifically formulated infrared light-transmitting black dye with controlled molecular structure and optical properties. By changing from conventional pigments to this specialized dye and optimizing its concentration (0.1-5 parts by mass per 100 parts resin), the patent achieves both adequate temperature rise suppression and high infrared light transmittance.
Solution Approach 2:
The patent combines the infrared light-transmitting black dye with a specifically designed composite resin system (PBT base with controlled amounts of noncrystalline resins). This composite material approach ensures that the dye's infrared transmission capability is fully realized while the resin matrix provides structural integrity and additional optical optimization.
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 effectively suppresses temperature rises, maintains high heat resistance, and achieves excellent anti-fogging properties, ensuring the blackness and designing features of lamp parts without surface melting, even under concentrated sunlight.
Implementation Method 1
an infrared light-transmitting black dye (D)... An average value of transmittances, for wavelengths of 800 to 1100 nm, of a flat plate that is obtained from the polyester resin composition and has a thickness of 2 mm is 5% or higher and less than 20%
Data Source
AI summary
The present invention relates to a polyester resin composition which has an excellent infrared light-transmitting property, and is excellent in heat resistance and low gas emission, and is suitable for use as black colored design parts (particularly as lamp parts). According to the present invention, there is provided a polyester resin composition containing, per 100 parts by mass of a polyester resin, 0.005 to 20 part(s) by mass of an inorganic filler that has an average particle size of 3 μm or less, 0.05 to 3 part(s) by mass of a polyfunctional glycidyl group-containing styrene polymer and 0.5 to 3 part(s) by mass of an infrared light-transmitting black dye, wherein the polyester resin composition satisfies the following requirements (1) and (2). (1) An average value of transmittances, for wavelengths of 800 to 1100 nm, of a flat plate that is obtained from the polyester resin composition and has a thickness of 2 mm is 5% or higher and less than 20%. (2) Color-L≤7.