Diamond-like Carbon Coating for Beverage Container Strength

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Solution Overview

Problem

Beverage containers, particularly glass and PET, face issues with mechanical strength due to surface flaws and degradation from manufacturing processes, mechanical forces, and chemical attacks, leading to reduced reusability and increased waste.

Innovation Solution

Applying a diamond-like carbon (DLC) coating with a thickness of 0.01 µm to 0.05 µm via a high-energy deposition process, combined with SnO2 or stearate coatings, enhances the mechanical strength and maintains optical clarity of PET containers, reducing susceptibility to scuffing and extending their life cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass is used for beverage containers to achieve optical clarity and chemical durability, then the containers can be cleaned and refilled multiple times, but long term exposure to natural elements and aggressive caustic washes cause surface degradation and scratching that reduce mechanical strength and aesthetic appearance

Engineering Contradiction:
ImprovereusabilityVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies a diamond-like carbon (DLC) coating on the exterior surface of glass beverage containers. This composite structure combines the optical clarity and chemical durability of glass with the mechanical strength, scratch resistance, and surface hardness of DLC, resolving the contradiction between reusability and mechanical strength by protecting the glass surface from degradation during repeated washing and handling cycles

Inventive Principle:
Principle #40Composite materials

2Strength

If PET containers are used as an alternative to glass, then mechanical strength and resistance to caustic washing are improved, but surface flaws and neck/base cracking still occur after 20 or more refilling cycles

Engineering Contradiction:
Improvemechanical strengthVSAvoidreusability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies a diamond-like carbon (DLC) coating on PET containers to create a composite structure. The DLC layer provides enhanced surface hardness, scratch resistance, and protection against caustic stress cracking, while the underlying PET maintains its formability and basic mechanical properties. This extends the reusable life cycle beyond 20 cycles by preventing surface flaw propagation and neck/base cracking

Inventive Principle:
Principle #40Composite materials

3Reliability

If a protective coating is applied to increase mechanical strength and reduce surface flaws, then reusability and bottle cycle time increase, but the coating process adds complexity to manufacturing

Engineering Contradiction:
ImprovereusabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a physical vapor deposition (PVD) process to apply the diamond-like carbon coating, which replaces more complex chemical coating methods. The PVD process uses physical sputtering or evaporation techniques to deposit the DLC layer, providing uniform coverage, precise thickness control, and compatibility with existing container manufacturing lines, thereby minimizing added manufacturing complexity while achieving enhanced reusability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 DLC coating significantly increases the mechanical strength and reusability of containers, minimizing surface flaws and maintaining optical clarity, thereby reducing waste and manufacturing costs while providing long-lasting lubricity and resistance to caustic washing.

Implementation Method 1

the protective coating is applied via a high-energy deposition process utilizing an energy value of 25 eV or greater

Methodology Applied
Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentEP4095056B1Containers and methods for improved mechanical strength
Publication Date: 2024.04.17 THE COCA COLA CO
  • EP4095056B1 patent drawingFigure 1A~1B
  • EP4095056B1 patent drawingFigure 2~3
  • EP4095056B1 patent drawingFigure 4~5

AI summary

Containers (100) are provided that include a body structure having a top end (102) that defines an opening (104), a sealed base end (106), and a sidewall structure (108) extending between the top and base ends, in which the sidewall structure has an interior surface (110) and an exterior surface (112), the interior surface defining an interior space (114), and a protective coating (116) that includes a diamond-like carbon on at least a portion of the exterior surface of the sidewall structure. Methods for enhancing the mechanical strength of containers are also provided.