Multi-section plastic component with non-elastomeric thermoplastic connection

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Solution Overview

Problem

The existing methods for producing multi-part plastic components using thermoplastic elastomers result in adhesives that are difficult to paint, leading to aesthetic issues with visible components like vehicle outer skin parts, as thermoplastic elastomers have a low modulus of elasticity and poor paintability.

Innovation Solution

A method involving the use of non-elastomeric thermoplastics with high melt flow indices, such as polyolefins, to connect injection-molded parts, which allows for better paintability and increased rigidity by forming a plastic connection component with a Shore D hardness of at least 60, enabling effective painting of both parts and the connecting component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thermoplastic elastomers are used to connect injection-molded parts, then ease of processing and flowability are improved, but paintability deteriorates due to extremely low modulus of elasticity

Engineering Contradiction:
Improveease of processingVSAvoidpaintability
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material parameter from thermoplastic elastomer to non-elastomeric thermoplastic, specifically selecting materials with high melt flow index (MFR ≥ 70 g/10min) to achieve both ease of processing and good paintability. This parameter change resolves the contradiction by finding a material that maintains flowability while eliminating the paintability issue caused by low modulus of elasticity.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If thermoplastic elastomers are used as adhesive, then flowability is improved, but rigidity of the multi-part component deteriorates

Engineering Contradiction:
ImproveflowabilityVSAvoidrigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the material class from elastomeric to non-elastomeric thermoplastic, selecting materials with specific properties (high MFR ≥ 70 g/10min, Shore D hardness ≥ 60) that provide both adequate flowability for injection molding and sufficient rigidity for the final component. This resolves the contradiction between flowability and rigidity.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If adhesive made from thermoplastic elastomer is used to join parts, then ease of joining is improved, but external appearance deteriorates when adhesive is visible

Engineering Contradiction:
Improveease of joiningVSAvoidexternal appearance
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The patent changes the material from thermoplastic elastomer to non-elastomeric thermoplastic with high melt flow index and appropriate hardness (Shore D ≥ 60). This material change allows the connecting component to be painted effectively, resolving the external appearance issue while maintaining ease of joining through injection molding.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3285983B1Method for producing a multi-section plastic component, and a multi-section plastic component
Publication Date: 2021.08.04 BAYERISCHE MOTOREN WERKE AG
  • EP3285983B1 patent drawingFigure 1~2
  • EP3285983B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a multi-section plastic component in which a first plastic injection-moulded individual part (10) and a second plastic injection-moulded individual part (20) are formed and said plastic injection-moulded individual parts (10, 20) are joined by injecting a plastic moulding compound. Said plastic moulding compound is a non-elastomeric thermoplastic and forms a plastic connecting component (30) following a curing process. Said plastic injection-moulded individual parts (10, 20) and plastic connecting component (30) are then at least partially painted. The invention also relates to a multi-section plastic component.