Polyester Preform Reheat Rate via Tungsten Oxide Nanoparticles

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Solution Overview

Problem

Current polyester compositions used in packaging, such as PET, face challenges in achieving rapid reheat rates with minimal energy consumption while maintaining transparency and avoiding undesirable coloration, particularly in beverage containers where high transparency and minimal coloration are essential.

Innovation Solution

Incorporating tungsten oxide particles, specifically WO2.72, into polyester compositions to enhance reheat performance with reduced impact on transparency and color, offering improved reheat rates and efficiency while maintaining acceptable optical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional reheat additives (carbon black, graphite, iron oxide) are added to increase infrared energy absorption, then reheat rate is improved, but visual appearance deteriorates (haze increases, color darkens)

Engineering Contradiction:

Improvereheat rateVSAvoidvisual appearance (brightness and color)

Core Design Contradiction:

SpeedVSIllumination intensity

Solution Approach 1:

The invention changes the optical absorption parameters of the polymer by incorporating tungsten oxide nanoparticles with specific size ranges (5-50 nm) and controlled concentrations (10-100 ppm). These parameter changes enable selective absorption in the infrared region while maintaining transparency in the visible spectrum, thus improving reheat rate without compromising visual appearance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system by combining polyester polymer matrix with tungsten oxide nanoparticles. This composite approach allows the material to exhibit both the structural properties of polyester and the enhanced infrared absorption properties of tungsten oxide, achieving improved reheat characteristics while maintaining optical clarity

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If quantity of reheat additive is decreased to retain acceptable brightness and color, then visual appearance is improved, but reheat rate decreases

Engineering Contradiction:

ImprovebrightnessVSAvoidreheat rate

Core Design Contradiction:

Illumination intensityVSSpeed

Solution Approach 1:

The invention utilizes the unique optical properties of tungsten oxide nanoparticles with specific size parameters (5-50 nm) that exhibit strong infrared absorption cross-sections. This allows achieving high reheat rates at very low concentration levels (10-100 ppm), thus maintaining brightness while improving reheat performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention effectively copies the desirable infrared absorption property from conventional blackbody absorbers into a nanoparticle form that can be incorporated at trace levels. The tungsten oxide nanoparticles replicate the heat absorption function of much larger quantities of conventional additives without their adverse visual effects

Inventive Principle:

Principle #26Copying

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 use of tungsten oxide particles in polyester compositions results in faster reheat rates and reduced energy consumption while preserving high transparency and minimal coloration, making them suitable for beverage containers and other packaging applications.

Implementation Method 1

polyesters, especially PET, absorb electromagnetic radiation poorly in the region from 500 nm to 1,500 nm. Thus, in order to maximize energy absorption from the lamps and increase preforms' reheat rate, materials that will increase infrared energy absorption are sometimes added to PET

Methodology Applied

Scientific EffectInfrared absorption: Absorption (EM radiation)