Polyetherimide Sulfone Blend for Optical Clarity

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Solution Overview

Problem

Current high heat polymers used in optical applications face challenges with poor melt processability and high cost, while also lacking a balance of thermal and optical properties, particularly in maintaining transparency and resistance to high temperatures.

Innovation Solution

A thermoplastic composition comprising a blend of first and second polyetherimide sulfones with specific glass transition temperatures and melt indices, combined with recycled polyetherimide sulfones to enhance thermal and optical properties, such as near-infrared transmission, yellowness index, and haze, is developed through melt-mixing and extrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polyetherimides are used to achieve high heat resistance, then glass transition temperature is improved, but melt processability deteriorates

Engineering Contradiction:

Improveglass transition temperatureVSAvoidmelt processability

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent uses a composite material system consisting of polyetherimide sulfone resin blended with polysulfone resin. This combination allows the composition to achieve both high heat resistance (glass transition temperature ≥220°C) and improved melt processability. The polysulfone component acts as a processability enhancer while the polyetherimide sulfone provides the thermal stability, creating a synergistic effect that resolves the contradiction between these two properties.

Inventive Principle:

Principle #40Composite materials

2Temperature

If polyetherimide sulfones are used to achieve high heat resistance and transparency, then thermal stability is improved, but cost increases

Engineering Contradiction:

Improvethermal stabilityVSAvoidcost

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The patent modifies the compositional parameters by blending polyetherimide sulfone with polysulfone in specific ratios (polyetherimide sulfone content: 10-90 wt%, preferably 30-70 wt%). This parameter optimization allows reduction of the expensive polyetherimide sulfone content while maintaining the required glass transition temperature (≥220°C) and optical transparency, thereby reducing material cost without sacrificing performance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes part of the expensive polyetherimide sulfone with cheaper polysulfone resin. While polysulfone has lower inherent heat resistance, the blended composition maintains the required thermal performance through synergistic effects, effectively using a lower-cost material to reduce overall composition cost while meeting performance specifications.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Temperature

If polyetherimide sulfones are used to achieve high heat resistance, then thermal properties are improved, but optical properties deteriorate

Engineering Contradiction:

Improveheat resistanceVSAvoidtransparency

Core Design Contradiction:

TemperatureVSIllumination intensity

Solution Approach 1:

The patent creates a composite material system where polyetherimide sulfone is blended with polysulfone resin. This combination leverages the high heat resistance of polyetherimide sulfone and the excellent optical clarity of polysulfone. The resulting composition achieves both high transparency and heat resistance, with the polysulfone component compensating for any optical degradation while maintaining thermal stability through the polyetherimide sulfone content.

Inventive Principle:

Principle #40Composite materials

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 achieves improved thermal stability, optical clarity, and cost-effectiveness by balancing glass transition temperatures, melt indices, and optical properties, making it suitable for high heat optical applications like lenses and filters.

Implementation Method 1

a first polyetherimide sulfone having a glass transition temperature of 250 to 290°C, preferably 260 to 270°C; and 10 to 90 wt.%, preferably 10 to 75 wt.%, more preferably 10 to 50 wt.% of a second polyetherimide sulfone having a glass transition temperature of 230 to 249°C, preferably 240 to 249°C

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

a transmission of greater than or equal to 4%, preferably 4.5 to 25%, more preferably 6 to 20%, determined according to ASTM D1003; and a haze of less than or equal to 12%, preferably 5 to 11% more preferably 6 to 10%, determined according to ASTM D1003

Methodology Applied

Scientific EffectLight transmission:

Data Source

PatentEP3331938B1Polyetherimide sulfone compositions, method of manufacture, and articles prepared therefrom

Publication Date: 2019.09.25 SABIC GLOBAL TECHNOLOGIES BV

AI summary

A thermoplastic composition is described herein including a first polyetherimide sulfone having a glass transition temperature of 250 to 290ºC, and a second polyetherimide sulfone having a glass transition temperature of 230 to 249ºC. The composition has an advantageous combination of optical properties including improved yellowness index, transmission, and haze. A method of manufacturing the thermoplastic composition and articles including the thermoplastic composition are also described. A method for improving the optical properties of a thermoplastic composition is also disclosed, where the method includes melt mixing the first and second polyetherimide sulfones, each having a glass transition temperature as defined herein. The method provides a composition having at least one of improved yellowness, haze, and transmission.