Lightweight Panel Dual-Adhesive Bonding to Reduce Polyurethane Cost

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Solution Overview

Problem

The production of lightweight panels is hindered by the difficulty and expense of processing polyurethane adhesive, which is commonly used to bond cover layers to a honeycomb middle layer.

Innovation Solution

Employing a combination of a fast-curing assembly adhesive and a slower-curing end adhesive, where the assembly adhesive provides initial fixation and stabilization, allowing for reduced usage of expensive polyurethane adhesive and enabling faster processing, while the end adhesive achieves durable bonding over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polyurethane adhesive is used to bond cover layers to the middle layer, then bonding strength is achieved, but processing difficulty and cost increase

Engineering Contradiction:
Improvebonding strengthVSAvoidprocessing ease
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The bonding process is divided into two distinct stages using two different adhesives: a fast-curing assembly adhesive for initial positioning and a slow-curing end adhesive for final bonding. This segmentation allows each adhesive to be optimized for its specific function, reducing overall processing difficulty while maintaining bonding strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the curing time parameter of the adhesive by using two adhesives with different curing characteristics. The assembly adhesive has a short curing time for rapid fixation, while the end adhesive has a long curing time for durable bonding, allowing optimization of both processing speed and final bond strength.

Inventive Principle:
Principle #35Parameter changes

2Strength

If polyurethane adhesive is used to bond cover layers to the middle layer, then bonding strength is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvebonding strengthVSAvoidadhesive cost
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The bonding function is segmented between two adhesives with different cost structures. The assembly adhesive is used in smaller quantities for initial fixation, while the end adhesive, which can be less expensive, provides the final bonding strength, thereby reducing overall adhesive cost while maintaining bond quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The assembly adhesive serves as a temporary, short-lived bonding agent that provides only initial fixation before being replaced by the end adhesive. This allows the use of a cheaper adhesive for the temporary bonding function, reducing overall manufacturing cost.

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

3Strength

If only end adhesive is used for bonding, then final bond strength is achieved, but processing time increases

Engineering Contradiction:
Improvefinal bond strengthVSAvoidcuring time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The assembly adhesive performs a preliminary bonding action that provides immediate fixation and stabilization. This preliminary action allows the panels to be positioned and secured while the end adhesive slowly cures, effectively reducing the overall processing time without compromising final bond strength.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bonding process occurs in two periodic stages: first the assembly adhesive provides rapid initial bonding, then the end adhesive provides slower final bonding. This periodic action allows optimization of both time and strength by having different bonding phases with different speed characteristics.

Inventive Principle:
Principle #19Periodic action

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

This approach reduces manufacturing effort and costs by minimizing the amount of expensive adhesive used, allowing for quicker processing and achieving final strength with a less expensive, easier-to-process adhesive, while maintaining the stability and heat resistance required for lightweight panels.

Implementation Method 1

an assembly adhesive and an end adhesive are provided as the adhesive, that the assembly adhesive is a PU adhesive, that the middle layer is covered with at least one of the two cover layers is connected at least in sections by the assembly adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the middle layer is connected to at least one of the two cover layers at least in sections by the end adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP1992759B1Lightweight construction board and method for producing a lightweight construction board.
Publication Date: 2020.07.08 FRITZ EGGER GMBH & CO OG
  • EP1992759B1 patent drawingFigure 1a~1c

AI summary

The lightweight board (1), especially for room doors, has two outer layers (2,3) and a center layer (4) bonded together at least in sections by an adhesive as a mounting adhesive (5), of a fusible adhesive or foam, and final bonding adhesive (6) of a fusible or dispersion or polycondensation adhesive or a water glass glue, in different and neighboring sections. The setting time of final adhesive is longer than that of the mounting adhesive.