Steel-Polymer Composite Weight Reduction Bake Stability

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Solution Overview

Problem

Existing composite materials for automotive components fail to achieve significant weight reduction due to polymeric layer softening or melting under automotive bake temperatures, leading to adhesion loss and shape changes, and often require expensive processing methods or are prone to corrosion from humidity.

Innovation Solution

A composite material comprising a polymeric core layer with a low shear flow value and high melting temperature, sandwiched between steel layers, which includes fillers and polymers that maintain adhesion and resist flow at elevated temperatures, and can be processed using cost-effective methods like extrusion or calendaring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a polymeric material is used in sandwich composite materials to reduce weight, then weight reduction is achieved, but the polymeric material softens or melts under automotive bake temperatures causing adhesion loss and shape changes

Engineering Contradiction:

Improveweight of composite materialVSAvoidadhesion between polymeric layer and metallic layers

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent changes the thermal parameters of the polymeric core layer by selecting polymers with melting temperatures of at least 180°C and glass transition temperatures of at least 180°C. This parameter change ensures the polymer maintains its structural integrity and adhesion properties during automotive bake cycles that typically reach temperatures below 180°C, thereby resolving the contradiction between weight reduction and adhesion reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure consisting of a polymeric core layer sandwiched between two steel layers. The steel layers provide structural support and thermal stability, while the polymeric core provides weight reduction. This composite material approach allows the system to achieve both weight reduction and maintained adhesion under bake temperatures, as the steel layers constrain the polymeric layer and prevent excessive deformation.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the polymeric layer has low viscosity to facilitate processing, then ease of manufacture is improved, but the polymeric material flows between metallic layers under heat and pressure

Engineering Contradiction:

Improveprocessing of polymeric layerVSAvoidshape stability of composite material

Core Design Contradiction:

Ease of manufactureVSShape

Solution Approach 1:

The patent carefully balances the viscosity parameters of the polymeric material. The polymer is selected to have sufficient viscosity at processing temperatures to prevent excessive flow between the metallic layers, while still allowing for adequate formability during stamping operations. The high melting and glass transition temperatures of the polymer provide a safety margin that prevents flow under typical automotive bake conditions, resolving the contradiction between ease of manufacture and shape stability.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If hygroscopic polymers are used in the polymeric layer, then ease of manufacture is improved, but long-term durability is reduced due to moisture-induced corrosion and adhesion loss

Engineering Contradiction:

Improveprocessing of polymeric layerVSAvoidlong-term durability of composite material

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters of the polymeric core layer by selecting non-hygroscopic polymers with low moisture absorption characteristics. This parameter change eliminates the moisture absorption pathway that would lead to corrosion of the steel layers and loss of adhesion, thereby resolving the contradiction between ease of manufacture and long-term durability. The selected polymers maintain processability while providing superior moisture resistance for long-term durability.

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 composite material achieves weight reduction while maintaining structural integrity and adhesion during automotive oven bake exposure and humidity, with improved durability and resistance to denting and impact, and can be efficiently processed for automotive applications.

Implementation Method 1

the polymeric core layer has a high viscosity, so that flow of the polymeric core layer is reduced or eliminated when the composite material is exposed to an automotive paint bake oven

Methodology Applied

Scientific EffectViscosity: Viscometer

Implementation Method 2

The composite material preferably includes an adhesive component for adhering to the metal layers

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

The polymeric core layer includes one or more fillers and one or more polymers, so that the melt flow rate of the polymeric core layer is reduced

Methodology Applied

Scientific EffectPhysical constraint on polymer flow:

Data Source

PatentUS11338552B2Composite materials, vehicle applications and methods thereof

Publication Date: 2022.05.24 PRODUCTIVE RESEARCH LLC

AI summary

The teachings herein relate to improved composite materials offering weight reduction which are capable of withstanding automotive paint bake ovens.