Sandwich Panel Core Layer Using Maleic Anhydride Grafted Polypropylene

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Solution Overview

Problem

Conventional sandwich panels lack sufficient weight reduction and mechanical strength, and their elongation properties are limited due to poor compatibility between polyester-based fibers and polypropylene fibers, which also results in weak bonding between skin and core layers during processing.

Innovation Solution

A sandwich panel with a core layer made from a non-woven fiber aggregate structure comprising a mixture of polyester-based fibers and polypropylene composite fibers, where the polypropylene composite fibers include maleic anhydride polyolefin, enhancing compatibility and mechanical properties without the need for additional binders, and a needle-punching process is used to create the core layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polypropylene fiber is used as a binder in non-woven fiber aggregates with polyester-based fiber, then the core layer can be formed, but compatibility with polyester-based fiber is lowered and mechanical properties are deteriorated

Engineering Contradiction:
Improvecore layer formationVSAvoidmechanical properties
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent modifies the chemical parameters of the polypropylene fiber by grafting maleic anhydride onto it, changing its surface properties and chemical reactivity. This parameter change enables better compatibility with polyester-based fibers through improved interfacial adhesion, thereby enhancing mechanical properties while maintaining ease of manufacture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite fiber structure by combining polypropylene with grafted maleic anhydride groups. This composite material approach allows the binder fiber to simultaneously provide structural support and chemical compatibility with polyester fibers, resolving the contradiction between ease of manufacture and mechanical properties

Inventive Principle:
Principle #40Composite materials

2Strength

If adhesive is applied between skin layer and core layer, then bonding is achieved, but formability during processing is poor due to weak bonding force

Engineering Contradiction:
Improvebonding forceVSAvoidformability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent enables the core layer to bond with skin layers through its own inherent properties rather than requiring external adhesives. The maleic anhydride-grafted polypropylene fiber provides self-bonding capability through chemical affinity with polyester-based fibers, eliminating the need for separate adhesive application and maintaining formability during processing

Inventive Principle:
Principle #25Self-service

3Weight of moving object

If conventional core materials are used, then sandwich panel structure is achieved, but weight reduction and mechanical strength are insufficient

Engineering Contradiction:
Improveweight reductionVSAvoidmechanical strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent uses a composite non-woven fabric structure combining polyester-based fibers for strength and maleic anhydride-grafted polypropylene fibers for binding. This composite approach achieves both weight reduction compared to solid materials and improved mechanical strength through optimized fiber composition and interfacial adhesion

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the compositional parameters of the non-woven fabric by controlling the ratio of polyester-based fibers to polypropylene composite fibers. This parameter optimization allows tuning of both weight and mechanical strength properties to meet specific application requirements

Inventive Principle:
Principle #35Parameter changes

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 significantly improves flexural rigidity and flexural strength of the sandwich panel, allowing for its use in structural applications such as TV back covers, construction boards, and automotive components, while reducing manufacturing costs and process complexity.

Implementation Method 1

The maleic anhydride polyolefin is grafted with polyolefin and maleic anhydride

Methodology Applied
Scientific EffectGrafting:

Implementation Method 2

a needle-punching process is used to create the core layer

Methodology Applied
Scientific EffectMechanical interlocking:

Data Source

PatentEP4070947B1Molded body, sandwich panel using same and method for manufacturing same
Publication Date: 2024.11.27 LG HAUSYS LTD
  • EP4070947B1 patent drawingFigure 1~2

AI summary

The present invention relates to a molded body, a sandwich panel using same as a core layer, and a method for manufacturing same, the molded body having a non-woven fiber aggregate structure comprising two or more non-woven fiber aggregates. The molded body comprises a polyester-based fiber and a polypropylene composite fiber, wherein the polypropylene composite fiber comprises polypropylene and maleic anhydride polyolefin.