Glossy Blow-Molded Container via Micro-Phase Interference

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Solution Overview

Problem

Thermoplastic materials with low transmittance, such as polyethylene and polypropylene, face challenges in achieving a glossy appearance due to high light absorption and reflection, making it difficult to produce glossy containers using extrusion blow molding, which also results in a less smooth surface.

Innovation Solution

A micro-layering structure is formed by adding an additive with a specific Solubility Parameter and Refractive Index difference to the thermoplastic material, reducing the Total Luminous Transmittance to around 53%, creating a light interference effect for a glossy appearance without using expensive pearlescent agents or metallocene materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If thermoplastic materials with low transmittance (e.g., PE, PP) are used, then manufacturing cost is reduced, but glossy appearance cannot be achieved due to high light absorption and reflection

Engineering Contradiction:
ImprovetransmittanceVSAvoidglossy appearance
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent creates a composite material system consisting of thermoplastic polymer matrix combined with immiscible additive domains. This composite structure allows low-transmittance materials like PE and PP to achieve glossy appearance through light interference effects at the micro-scale interfaces between the polymer and additive phases, resolving the contradiction between material cost and aesthetic quality.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention introduces localized immiscible additive domains distributed within the thermoplastic matrix, creating local refractive index variations at the micro-scale. These localized structures generate light interference effects that produce glossy appearance specifically at the container surface, while the bulk material maintains its low-transmittance, cost-effective properties.

Inventive Principle:
Principle #3Local quality

2Productivity

If extrusion blow molding is used for low transmittance materials, then manufacturing efficiency is improved, but surface smoothness deteriorates leading to reduced glossiness

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidsurface smoothness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the optical parameters of the material system by introducing additives with different refractive indices and solubility parameters. This creates micro-phase separation that generates light interference effects, transforming the surface optical properties to achieve glossiness despite the inherently rough surface morphology produced by extrusion blow molding processes.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If expensive materials like metallocene PE or pearlescent agents are used, then glossy appearance is improved, but manufacturing cost increases

Engineering Contradiction:
Improveglossy appearanceVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The invention replaces expensive, non-recyclable pearlescent agents with inexpensive, recyclable thermoplastic additives that achieve similar glossy effects through immiscibility-driven light interference. This substitution maintains aesthetic quality while dramatically reducing material costs and improving environmental sustainability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The thermoplastic additive system performs multiple functions: it modifies optical properties to create glossy appearance, maintains processability during extrusion blow molding, and enables recyclability. The additive essentially services the system by providing glossy appearance without requiring expensive external pearlescent agents.

Inventive Principle:
Principle #25Self-service

4Manufacturing precision

If transmittance is reduced to achieve glossy effect, then light interference is improved, but total luminous transmittance drops below acceptable levels

Engineering Contradiction:
Improveglossy effectVSAvoidtotal luminous transmittance
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The invention transitions from bulk material modification to micro-scale structural modification. By creating immiscible additive domains at the micro-scale (0.1-10 micrometers), the system generates light interference effects in the optical dimension without significantly affecting bulk transmittance. The micro-structured interfaces provide glossy appearance while maintaining adequate light transmission for functional requirements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution achieves a noticeable glossy effect and improved surface smoothness in containers made from a broader range of thermoplastic materials, enhancing recyclability and reducing the need for costly additives, while maintaining efficiency in the extrusion blow molding process.

Implementation Method 1

creating a light interference effect for a glossy appearance

Methodology Applied
Scientific EffectLight interference: Interference

Implementation Method 2

additive with a specific Solubility Parameter and Refractive Index difference

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2988932B1A glossy container
Publication Date: 2022.02.16 PROCTER & GAMBLE CO
  • EP2988932B1 patent drawingFigure 1~2A
  • EP2988932B1 patent drawingFigure 2B~3
  • EP2988932B1 patent drawing

AI summary

A blow-molded container comprises a layer having a thermoplastic material and an additive, wherein the thermoplastic material and the additive have a Solubility Parameter difference of from about 0.5cal1/2cm-3/2to about20cal1/2cm-3/2, and have a Refractive Index difference of from about0.1to about 1.5. Such a container has a desirable glossy appearance.