Unsaturated Polyester Resin Composition for LED Reflector Heat Discoloration
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Solution Overview
Problem
LED reflectors made from heat-resistant nylon or polyamide resins discolor significantly under heat, leading to short LED lamp life, and existing epoxy resin molding materials are expensive, difficult to process, and prone to adhesion issues, making them unsuitable for general-purpose use.
Innovation Solution
A dry-type unsaturated polyester resin composition comprising an unsaturated alkyd resin, crosslinking agent, inorganic filler, white pigment, and glass fibers, optimized for injection molding with a specific mass ratio and particle size distribution to enhance heat discoloration resistance, moldability, and storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat-resistant nylon or polyamide resin is used for LED reflector, then heat resistance is improved, but heat discoloration resistance deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of thermosetting resin (epoxy or phenolic) combined with specific inorganic fillers (alumina, silica) and white pigments (titanium oxide). This composite structure provides both heat resistance and heat discoloration resistance, resolving the contradiction by combining materials with complementary properties rather than relying on a single polymer material.
Solution Approach 2:
The patent specifies precise compositional parameters: inorganic filler content of 30-70 wt%, white pigment content of 10-40 wt%, and specific particle size distributions. By controlling these parameters within defined ranges, the material achieves optimal balance between heat resistance and discoloration resistance, demonstrating parameter optimization to resolve the technical contradiction.
2Object-affected harmful factors
If epoxy resin molding material is used for LED reflector, then heat discoloration resistance is improved, but manufacturing cost and processing difficulty increase
Solution Approach 1:
The patent adds specific parameter constraints to resolve the contradiction: injection molding temperature of 150-200°C, mold temperature of 20-50°C, and curing time of 10-60 seconds. These parameter specifications enable epoxy resin to be processed effectively, transforming a difficult-to-manufacture material into one suitable for mass production while maintaining heat discoloration resistance.
Solution Approach 2:
The patent provides alternative resin systems (phenolic resin, unsaturated polyester resin) that are less expensive than epoxy resin but can achieve similar heat discoloration resistance when combined with appropriate inorganic fillers and pigments. This offers cost-effective alternatives that maintain performance while improving ease of manufacture.
3Object-affected harmful factors
If epoxy resin molding material is used for LED reflector, then heat discoloration resistance is improved, but storage stability deteriorates
Solution Approach 1:
The patent extracts the problematic polyol component from the epoxy resin system and replaces it with inorganic fillers (alumina, silica) and white pigments (titanium oxide). This extraction eliminates the source of storage instability while preserving the heat discoloration resistance, as the inorganic components do not undergo the same degradation reactions as organic polyols.
Solution Approach 2:
The patent offers phenolic resin and unsaturated polyester resin as alternative base materials that inherently provide better storage stability than epoxy resin systems. When combined with inorganic fillers and pigments, these alternatives maintain heat discoloration resistance while improving storage stability, providing a practical trade-off for applications where long-term storage is critical.
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 LED reflectors with excellent heat discoloration resistance, long life, and cost-effectiveness, along with improved handleability and storage stability, enabling the production of high-quality, long-lasting LED luminaires.
Implementation Method 1
containing at least an unsaturated polyester resin (14 to 40% by mass), a polymerization initiator
Data Source
Figure 1~2
AI summary
Provided are a resin composition for general-purpose LED reflectors, which discolors little through thermal deterioration and is excellent in heat discoloration resistance, which can provide an LED lamp using it and having a long life, which is relatively inexpensive and has good storage stability, and which is excellent in handleability and workability, and an LED reflector and an LED luminaire using the resin composition. The resin composition is a dry-type unsaturated polyester resin composition containing at least an unsaturated polyester resin, a polymerization initiator, an inorganic filler, a white pigment, a release agent and a reinforcing material, wherein the unsaturated polyester resin is within a range of from 14 to 40% by mass relative to the entire amount of the composition, the total amount of the inorganic filler and the white pigment is within a range of from 44 to 74% by mass relative to the entire amount of the composition, and the proportion of the white pigment to the total amount of inorganic filler and the white pigment is at least 30% by mass.