Instrument Panel Skin TPU Composite Low-Temperature Airbag Deployment

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Solution Overview

Problem

Current manufacturing processes for vehicle instrument panels, such as vacuum forming, spray urethane, and slush molding, face issues with brittleness, shredding, and undesirable 'hand' during low-temperature airbag deployments, necessitating a material with improved aesthetic touch and functional performance.

Innovation Solution

The development of an instrument panel skin comprising a thermoplastic urethane elastomer and a propylene-ethylene copolymer, including a polyol, chain extender, organic diisocyanate, hindered amine light stabilizer, and benzotriazole ultraviolet stabilizer, which is formed using a slush molding method to provide enhanced touch characteristics and low-temperature airbag deployment functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vacuum forming process is used, then manufacturing efficiency is improved, but the instrument panel becomes brittle and exhibits hard hand at low temperatures

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidlow temperature performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses a composite material system consisting of TPU elastomer as the base polymer, modified with specific amounts of PVC (5-30 phr) and CPE (5-30 phr). This composite formulation combines the flexibility and low-temperature performance of TPU with the aesthetic properties and processability of PVC/CPE, resolving the contradiction between manufacturing efficiency and low-temperature reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters by incorporating specific ratios of TPU, PVC, and CPE, along with controlled amounts of plasticizers (10-50 phr) and stabilizers. These parameter changes transform the material properties to achieve both vacuum forming processability and superior low-temperature flexibility without brittleness.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If spray urethane process is used, then weatherability is improved, but the instrument panel exhibits shredding and sharding during low temperature airbag deployment

Engineering Contradiction:

ImproveweatherabilityVSAvoidlow temperature flexibility

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent creates a composite material system that integrates TPU elastomer with modified PVC and CPE components. This composite structure provides the weatherability needed for automotive interiors while the elastomeric nature of TPU and the flexible modifiers prevent shredding and sharding during low-temperature airbag deployment.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality modification by incorporating specific functional components (CPE for flexibility, plasticizers for low-temperature performance) into the material system at controlled concentrations, allowing the material to exhibit both weatherability and low-temperature flexibility in different regions of the instrument panel.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If modified PVC is used, then aesthetic touch properties are improved, but the material exhibits shredding and sharding during low temperature airbag deployment

Engineering Contradiction:

Improveaesthetic touch propertiesVSAvoidlow temperature flexibility

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent formulates a composite material where modified PVC (with CPE grafts) serves as the aesthetic component providing desirable touch properties, while the TPU elastomer base and additional CPE content ensure low-temperature flexibility and prevent shredding during airbag deployment.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent adjusts the chemical composition parameters by controlling the phr levels of PVC, CPE, and plasticizers to achieve the optimal balance between aesthetic touch properties and low-temperature flexibility, preventing the shredding and sharding issues that occur with conventional modified PVC.

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 achieves improved touch characteristics and maintains elongation properties during low-temperature airbag deployments, with significant heat stability and resistance to aging, ensuring the instrument panel skin performs effectively and retains its properties over time.

Implementation Method 1

The urethane based resin composition is heated to a sufficient temperature to form a layer over at least a portion of the mold tool

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

The instrument panel skin comprises residues of a thermoplastic urethane elastomer and a propylene-ethylene copolymer

Methodology Applied

Scientific EffectMixing:

Data Source

PatentUS7833623B2Modified slush moldable TPU for instrument panels with seamless airbag deployment capability

Publication Date: 2010.11.16 INTERNATIONAL AUTOMOTIVE COMPONENTS GROUP NORTH AMERICA INC

AI summary

A vehicle instrument panel skin comprises residues of a thermoplastic urethane elastomer and a propylene-ethylene copolymer. The thermoplastic urethane elastomer includes a polyol, an organic diisocyanate, an optional chain extender, and an optional hindered amine light stabilizer and a benzotriazole ultraviolet stabilizing agent. A method for forming the instrument panel skin is also provided.