Polycarbonate Resin Composition for Light Blocking and Transparency

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Solution Overview

Problem

Conventional methods fail to adequately address the issue of coloration in polycarbonate resin molded products, particularly yellowing, which affects transparency and light blocking properties, especially in applications requiring high transparency and protection against ultraviolet and short-wavelength visible light.

Innovation Solution

The amount of organic peroxide in the polycarbonate resin is controlled within a specific range (4,000 to 12,000 counts per mg) to achieve both excellent transparency and effective light blocking properties, particularly in the ultraviolet and short-wavelength visible light regions, by optimizing the production process including the use of antioxidants and inert gas environments during extrusion and injection molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional methods (antioxidants, inert gas, deoxygenization) are used to prevent coloration, then some transparency improvement is achieved, but yellowing and coloration cannot be sufficiently suppressed

Engineering Contradiction:
ImprovetransparencyVSAvoidyellowing and coloration
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameter by introducing a peroxide decomposing agent that actively decomposes peroxides formed during processing. This transforms the approach from passive prevention (antioxidants) to active decomposition, achieving superior coloration suppression and transparency improvement without compromising other properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The peroxide decomposing agent acts as an intermediary substance that specifically targets and decomposes peroxides. This intermediary mechanism provides focused action on the harmful peroxide compounds without interfering with other essential polymerization and processing reactions, resolving the contradiction between preventing coloration and maintaining material integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If dyes or reflective layers are added to block ultraviolet and short-wavelength visible light, then light blocking performance is improved, but production complexity and cost increase

Engineering Contradiction:
Improveultraviolet and short-wavelength light blockingVSAvoidproduction process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent makes the polycarbonate resin itself multi-functional by enabling it to simultaneously provide structural integrity, optical clarity, and ultraviolet/short-wavelength light blocking. This is achieved through controlled peroxide decomposition that creates intrinsic light blocking capability without requiring separate dyeing or coating processes, thus eliminating production complexity while maintaining light blocking performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the light blocking function with the base resin material. Instead of adding separate functional layers or dyes, the peroxide decomposing agent is incorporated into the resin matrix, creating a unified material that provides both structural and optical protection functions in a single component, simplifying the overall product structure and manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

3Illumination intensity

If peroxide decomposing agent is added to enhance light blocking, then transparency and light blocking are improved, but resin composition complexity increases

Engineering Contradiction:
Improvetransparency and light blockingVSAvoidresin composition complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent optimizes the concentration parameter of the peroxide decomposing agent to fall within a specific range (0.01-5 wt%). This parameter control ensures sufficient peroxide decomposition for improved transparency and light blocking while preventing excessive addition that would cause composition complexity or adverse effects on polymerization and processing.

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

This approach results in polycarbonate resin molded products with enhanced transparency and light blocking capabilities, reducing yellowing and optical transmittance in the adverse light regions, without the need for additional additives or complex production processes, thus providing a cost-effective solution.

Implementation Method 1

an integrated value of an amount of chemiluminescence, derived from organic peroxide, of 4,000 to 12,000 counts per mg

Methodology Applied
Scientific EffectChemiluminescence: Chemiluminescence

Data Source

PatentEP3156453B1Polycarbonate resin composition, and molded article and method for manufacturing same
Publication Date: 2019.09.18 MITSUBISHI GAS CHEM CO INC
  • EP3156453B1 patent drawingFigure 1
  • EP3156453B1 patent drawingFigure 2
  • EP3156453B1 patent drawingFigure 3

AI summary

According to an embodiment, provided is a polycarbonate resin composition containing a polycarbonate resin, wherein a molded product of the polycarbonate resin composition has an integrated value of an amount of chemiluminescence derived from organic peroxide of 4,000 to 12,000 counts per mg of the molded product, and the integrated value of the amount of chemiluminescence is a value obtained by integrating the amount of chemiluminescence at a wavelength of 405 to 650 nm that is measured during 480 seconds in which under a nitrogen atmosphere the temperature is raised from 100°C to 350°C at a rate of 50°C/minute and thereafter is maintained at 350°C for 180 seconds.