Polycarbonate Resin Composition for Heat-Stable UVA Transmittance Control

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Solution Overview

Problem

Existing polycarbonate materials face challenges in maintaining excellent optical properties and heat stability, particularly under high temperature conditions, with existing solutions often compromising one property for the other, and there is a need to control transparency in specific wavelength regions for optical applications.

Innovation Solution

A polycarbonate resin composition incorporating [[4-(dimethylamino)phenyl]methylene] propanedioic acid dimethyl ester as a hindered amine UV absorber that selectively absorbs UVA at 420 nm or less, combined with polycarbonate resin, to enhance heat resistance and control light transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional UV absorbers or copolymerization methods are used to improve optical properties and heat resistance, then chemical resistance and heat resistance are increased, but optical properties (transmittance and shield effect) are deteriorated

Engineering Contradiction:

Improveheat resistanceVSAvoidoptical properties

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the chemical structure parameters of the UV absorber by introducing a specific hindered amine structure with particular molecular weight and purity specifications. This structural parameter change enables selective absorption at 420 nm while maintaining heat resistance, resolving the contradiction between optical properties and heat resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resin system combining polycarbonate base resin with the specific hindered amine UV absorber at optimized concentration ratios. This composite approach allows the UV absorber to provide optical filtering while the polycarbonate matrix maintains structural integrity and heat resistance, preventing the trade-off between optical and thermal properties

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If transmittance is reduced in specific wavelength region to improve shield effect, then optical shielding is improved, but heat stability is deteriorated due to polymer modification and discoloration

Engineering Contradiction:

Improveshield effectVSAvoidheat stability

Core Design Contradiction:

Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent converts the potentially harmful effect of UV absorption into a beneficial thermal stabilizing effect. The hindered amine structure, while absorbing UV at 420 nm, simultaneously acts as a heat stabilizer that prevents polymer degradation. The molecular structure is designed to dissipate absorbed energy as heat without causing polymer modification, turning the absorption event into a protective mechanism

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The hindered amine UV absorber serves as an intermediary substance between UV radiation and the polycarbonate polymer. It intercepts UV photons at 420 nm and through its specific molecular structure, dissipates the energy without transferring damaging effects to the polymer chains, thereby protecting the polymer from thermal and UV degradation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If existing UV absorbers are used to control transmittance, then shield effect is improved, but heat resistance is significantly lowered and polymer modification occurs

Engineering Contradiction:

Improvetransmittance controlVSAvoidheat resistance

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent fundamentally changes the parameter set of the UV absorber by specifying a hindered amine structure with particular molecular weight range, purity level, and chemical composition. These parameter changes distinguish it from conventional UV absorbers, enabling simultaneous achievement of transmittance control and heat resistance by modifying the molecular energy dissipation pathways

Inventive Principle:

Principle #35Parameter changes

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 inhibits discoloration and modifies transmittance under high temperatures, maintaining excellent mechanical properties and optical performance, suitable for optical molded articles like lenses.

Implementation Method 1

[[4-(dimethylamino)phenyl]methylene] propanedioic acid dimethyl ester as a hindered amine UV absorber that selectively absorbs UVA having a wavelength of 420 nm or less

Methodology Applied

Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentUS12624205B2Polycarbonate resin composition and optical molded article comprising the same

Publication Date: 2026.05.12 LG CHEM LTD

AI summary

The present disclosure relates to a polycarbonate resin composition exhibiting excellent heat stability and optical properties, and an optical molded article comprising the same. The polycarbonate resin composition includes polycarbonate resin; and [[4-(dimethylamino)phenyl]methylene] propanedioic acid dimethyl ester as a hindered amine UV absorber that selectively absorbs UVA having a wavelength of 420 nm or less.