PCT Resin Composition for LED Reflector Crystallization
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Solution Overview
Problem
Existing highly heat-resistant polyester resins used in LED components suffer from slow crystallization rates and poor impact resistance, which can lead to reduced moldability and mechanical properties, and excessive use of additives can further degrade these properties.
Innovation Solution
A polyester resin composition incorporating a polymer of aromatic dicarboxylic acid and alicyclic diol with a trans/cis isomer ratio of 2.3 or more, combined with white pigments and inorganic fillers, to enhance crystallization rate, moldability, and mechanical properties such as flexural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If highly heat-resistant polyester resins are used to improve heat resistance, then heat resistance is improved, but crystallization rate becomes slow and moldability deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of PCT resin as the base polymer, combined with specific inorganic fillers (talc, glass fibers) and nucleating agents. This composite structure allows the PCT resin to maintain its high heat resistance while the inorganic fillers and nucleating agents promote faster crystallization, thus resolving the contradiction between heat resistance and crystallization rate.
Solution Approach 2:
The patent changes the chemical composition parameters of the polyester resin by incorporating aromatic dicarboxylic acid components and specific diol components in controlled ratios. By adjusting these compositional parameters and adding nucleating agents, the crystallization kinetics are modified to achieve faster crystallization while preserving the high-temperature stability characteristic of PCT resin.
2Productivity
If additives such as inorganic fillers and nucleating agents are added to improve crystallization rate and impact resistance, then crystallization rate and impact resistance are improved, but moldability and mechanical properties deteriorate when excess amount is used
Solution Approach 1:
The patent precisely controls the concentration parameters of additives by specifying that talc is present at 1-10 parts by weight and glass fibers at 10-40 parts by weight per 100 parts of PCT resin. This quantitative control ensures optimal crystallization enhancement while preventing excessive additive content that would harm moldability and mechanical properties.
Solution Approach 2:
The patent applies different types of additives for different functions: talc primarily for nucleation and crystallization rate enhancement, glass fibers for mechanical reinforcement, and white pigments for optical properties. Each additive is optimized for its specific function, allowing the system to achieve improved crystallization and mechanical properties without compromising overall moldability.
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 significantly reduces solidification time during injection molding, improves moldability and mechanical properties, and minimizes deformation, making it suitable for LED reflectors with enhanced heat resistance and discoloration resistance.
Implementation Method 1
significantly reduce solidification time upon injection molding due to increased crystallization rate
Data Source
AI summary
A polyester resin composition includes: (A) polycyclohexylenedimethylene terephthalate (PCT) resin which is a polymer of terephthalic acid and cyclohexanedimethanol, wherein the cyclohexanedimethanol has a trans/cis isomer ratio of about 2.3 or more; (B) a white pigment, wherein the white pigment is titanium dioxide; and (C) inorganic fillers, wherein the inorganic fillers are glass fibers. A molded article formed from the polyester resin composition can exhibit improved mechanical properties and moldability, and thus can be suitable for light emitting diode (LED) reflectors.