Polyamide LED Reflection Plate Heat Resistance
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Solution Overview
Problem
Existing LED reflection plates face challenges in maintaining high light reflectance under both short-term and long-term heat exposure, particularly during production and usage environments, with existing materials showing significant decreases in reflectance due to thermal and oxidative deterioration.
Innovation Solution
A polyamide composition comprising a specific polyamide with a dicarboxylic acid unit predominantly made of terephthalic acid, titanium oxide, magnesium oxide, a phenolic antioxidant, and a phosphorus-containing antioxidant, in predetermined proportions, which provides enhanced heat resistance and stability to maintain high light reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat-resistant plastics are used for LED reflection plates, then the reflection plate can withstand high temperatures during production, but the light reflectance decreases significantly after short-term and long-term heat exposure
Solution Approach 1:
The patent uses a composite material system consisting of polyamide resin as the base matrix, titanium oxide particles as light scattering agents, and multiple antioxidants (phenolic and phosphorus-containing) as protective additives. This composite structure combines the heat resistance of polyamide with the light scattering properties of titanium oxide and the oxidative stability provided by antioxidants, achieving both high-temperature withstand capability and maintained light reflectance after heat exposure.
Solution Approach 2:
The patent introduces antioxidants as intermediary substances that mediate between the polyamide resin and oxygen during thermal exposure. The phenolic antioxidant (0.01-1.0 parts by mass) and phosphorus-containing antioxidant (0.01-1.0 parts by mass) act as sacrificial protectors that undergo oxidation reactions first, preventing direct oxidation of the polyamide resin and titanium oxide, thereby maintaining light reflectance stability during heat exposure.
2Reliability
If the content of antioxidants is increased to prevent thermal and oxidative deterioration, then the light reflectance stability improves, but the total antioxidant content exceeds the optimal range for maintaining high reflectance
Solution Approach 1:
The patent optimizes the parameters of antioxidant content by specifying precise ranges: phenolic antioxidant at 0.01-1.0 parts by mass and phosphorus-containing antioxidant at 0.01-1.0 parts by mass, with their combined total not exceeding 2.0 parts by mass per 100 parts by mass of polyamide resin. This parameter optimization balances the protective effect against oxidation with the need to maintain high light reflectance, avoiding excessive antioxidant content that could negatively impact optical properties.
Solution Approach 2:
The patent applies different types of antioxidants at different functional levels: phenolic antioxidants provide primary radical scavenging protection, while phosphorus-containing antioxidants provide secondary peroxide decomposition protection. This differentiated local quality approach ensures comprehensive protection with minimal total antioxidant content, as each antioxidant type addresses specific degradation mechanisms efficiently.
3Illumination intensity
If titanium oxide content is increased to enhance light scattering and reflectance, then the initial light reflectance improves, but the material becomes more susceptible to thermal and oxidative degradation
Solution Approach 1:
The patent introduces antioxidants as intermediary protective layers that shield titanium oxide particles from direct thermal and oxidative attack. The phenolic and phosphorus-containing antioxidants preferentially react with oxygen and free radicals generated during heat exposure, creating a protective chemical environment around the titanium oxide particles and preventing their oxidation and aggregation, thereby maintaining both high light reflectance and thermal stability.
Solution Approach 2:
The patent creates a multi-component composite system where titanium oxide (1-50 parts by mass per 100 parts by mass of polyamide) provides light scattering and reflectance enhancement, while the polyamide resin matrix provides structural integrity and heat resistance, and the antioxidant package (phenolic and phosphorus-containing) provides oxidative protection. This composite structure allows titanium oxide to function at optimal concentrations without suffering from excessive thermal and oxidative degradation.
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 thermal and oxidative degradation, ensuring a high and stable light reflectance even after short-term and long-term heat exposure, thereby extending the lifespan of LED reflection plates and light-emitting devices.
Implementation Method 1
a polyamide composition for an LED reflection plate, comprising a polyamide (A), titanium oxide (B)
Implementation Method 2
maintain a high light reflectance, at intense heat in LED package production and under the use environment
Implementation Method 3
the content of the phosphorus-containing antioxidant (E) satisfies the following expression (I): wherein the total content of the phenolic antioxidant (D) and the phosphorus-containing antioxidant (E) in the polyamide composition is 1.5 parts by mass or lower
Data Source
Figure 1~2
Figure 3
AI summary
There is provided a polyamide composition for an LED reflection plate, including a polyamide (A), a titanium oxide (B), a magnesium oxide (C), a phenolic antioxidant (D), and a phosphorus-containing antioxidant (E), wherein the polyamide (A) is a polyamide having a dicarboxylic acid unit comprising 50% by mol or more of terephthalic acid unit and a diamine unit and having a melting point of 280°C or higher; the phenolic antioxidant (D) does not have 4 or more phenol structures in its molecule; wherein the content of the titanium oxide (B) is 10 to 100 parts by mass, the content of the magnesium oxide (C) is 0.50 to 15.0 parts by mass, and the content of the phenolic antioxidant (D) is 0.10 to 0.80 part by mass, with respect to 100 parts by mass of the polyamide (A); and the content of the phosphorus-containing antioxidant (E) satisfies the following expression (I): 0.25≤mass ratioD component/E component≤3.0 There are also provided a reflection plate obtained by molding the composition, and a light-emitting device having the reflection plate.