PLA Candle Container with Microencapsulated APP Flame Retardant

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Solution Overview

Problem

Existing candle containers lack improved flame resistance and mechanical properties, and do not facilitate biodegradability after the consumption of flammable materials.

Innovation Solution

A plastic container made from a combination of polylactide (PLA) and microencapsulated ammonium polyphosphate (APP) with a melamin coating, which enhances fire resistance and mechanical properties while being biodegradable, is used. The PLA is composed of poly-L-lactide and poly-D-lactide isomers, and APP is microencapsulated to improve fire resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional plastic materials are used for candle containers, then ease of manufacture is maintained, but flame resistance and biodegradability are insufficient

Engineering Contradiction:
Improveflame resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite material system consisting of polylactide (PLA) as the base polymer and ammonium polyphosphate (APP) as the flame retardant additive. This composite approach allows the container to achieve improved flame resistance while maintaining biodegradability, as both components are compatible with composting conditions. The composite material resolves the contradiction by combining materials with complementary properties rather than relying on conventional plastics that resist fire but do not biodegrade.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the concentration of ammonium polyphosphate within a specific range of 0.1-10 wt% to achieve the desired flame resistance while maintaining manufacturability. By carefully controlling this parameter, the invention finds the optimal balance between fire safety performance and ease of manufacturing, avoiding both excessive complexity and insufficient protection.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If biodegradable materials like pure PLA are used, then biodegradability is improved, but flame resistance is insufficient

Engineering Contradiction:
ImprovebiodegradabilityVSAvoidflame resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Ammonium polyphosphate acts as an intermediary substance that bridges the gap between biodegradability and flame resistance. It is incorporated into the PLA matrix to provide fire protection during the candle-burning phase, while itself being compatible with biodegradation processes. This intermediary additive allows the container to satisfy both contradictory requirements: resisting fire during use and decomposing after use.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the inherent vulnerability of biodegradable PLA to fire into a benefit by incorporating flame retardant additives. The harmful flammability of pure PLA is transformed into controlled fire resistance through the APP additive, which releases protective gases and forms a protective char layer during combustion, while the entire system remains biodegradable.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If flame retardant additives are added to improve fire resistance, then flame resistance is improved, but mechanical properties may deteriorate

Engineering Contradiction:
Improveflame resistanceVSAvoidmechanical properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent specifies an optimized concentration range of 0.1-10 wt% for ammonium polyphosphate to achieve flame resistance while preserving mechanical properties. Within this parameter range, the flame retardant provides adequate fire protection without excessive degradation of the PLA matrix structure, thus maintaining the container's mechanical strength and integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flame retardant properties are distributed throughout the PLA matrix at controlled concentrations, creating local fire protection zones that do not significantly compromise the overall mechanical structure. The additive is dispersed to provide fire resistance where needed while minimizing impact on the bulk mechanical properties of the container.

Inventive Principle:
Principle #3Local quality

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 container exhibits improved flame resistance and mechanical properties, with combustion times exceeding 30 seconds in flammability tests, and demonstrates biodegradability, effectively addressing the limitations of previous designs.

Implementation Method 1

APP is microencapsulated to improve fire resistance

Methodology Applied
Scientific EffectFire resistance enhancement:

Implementation Method 2

The container exhibits improved flame resistance and mechanical properties, with combustion times exceeding 30 seconds in flammability tests, and demonstrates biodegradability

Methodology Applied
Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentEP3931259B1Container for candle product
Publication Date: 2024.02.21 MUELLER FAB SWIEC SPOKA AKCYJNA

AI summary

Container for candle product intended to be filled with a flammable material, through which a wick is passing. The container is provided with a bottom and with side walls and is made of plastic. The plastic is a polymer containing 40% to 99.99 wt.% of polylactide PLA and 0.01% to 60 wt.% of ammonium polyphosphate APP. The polylactide PLA may be a mixture of poly-L-lactide PLLA and poly-D-lactide PDLA isomers, wherein the mixture contains at least 80 wt.% of PLLA and not more than 20 wt.% of PDLA. Ammonium polyphosphate APP may be microencapsulated, wherein microcapsules have a diameter of 25μm to 55μm and may contain a melamin coating.