Thermoplastic Elastomer for Vehicle Weather Strip Sealing

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Solution Overview

Problem

The conventional assembly process of glass runs and inner-belts in vehicle weather strips results in gaps that increase wind noise and requires environmentally hazardous chemicals, leading to manufacturing defects and higher production costs.

Innovation Solution

A thermoplastic elastomer composition comprising 80-90 parts EPDM, 30-50 parts polybutene, 30-40 parts polypropylene, 110-130 parts paraffin oil, 0.7-0.9 parts peroxide cross-linking agent, and 0.5-0.8 parts antioxidant, which allows for integrally injection-molding of glass runs and inner-belts, eliminating the need for adhesives and reducing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If glass run and inner-belt are assembled separately using conventional methods, then manufacturing flexibility is maintained, but gaps form between components increasing wind noise and requiring hazardous chemicals for connection

Engineering Contradiction:
Improvewind noiseVSAvoidassembly process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the glass run and inner-belt into a single integrally molded component using the thermoplastic elastomer composition. This eliminates the gap between separately assembled parts that causes wind noise, while also eliminating the need for hazardous adhesives and primers in the assembly process.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a composite thermoplastic elastomer material containing EPDM, polybutene, polypropylene, and paraffin oil to create a joint that provides both structural integrity and sealing properties. This composite material enables integral molding that eliminates gaps and reduces wind noise without requiring additional assembly steps.

Inventive Principle:
Principle #40Composite materials

2Reliability

If separately manufactured glass run and inner-belt are connected using adhesives or primers, then connection is achieved, but environmentally hazardous chemicals are used and manufacturing defects increase

Engineering Contradiction:
Improvejoint connectionVSAvoidhazardous chemicals
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the need for hazardous adhesives and primers from the manufacturing process by using integral injection molding. The thermoplastic elastomer composition directly bonds the glass run and inner-belt in a single molding step, removing harmful chemicals from the system while maintaining reliable joint connection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The thermoplastic elastomer composition provides self-bonding capability through its molecular structure and processing characteristics. The material inherently adheres to both the glass run and inner-belt surfaces during injection molding, eliminating the need for external adhesives or primers to achieve reliable connection.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If conventional assembly methods are used, then separate manufacturing is maintained, but manufacturing defects such as burs increase production costs

Engineering Contradiction:
Improvecomponent manufacturingVSAvoidjoint quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines the manufacturing of glass run and inner-belt into a single integral molding process. This eliminates the need for separate assembly operations that generate manufacturing defects like burs, thereby improving joint quality while maintaining ease of manufacture through streamlined production.

Inventive Principle:
Principle #5Merging (Combining)

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 composition provides improved sealing, reduced noise, and lower manufacturing costs by enhancing adhesive force and processability, while being environmentally friendly and reducing the need for hazardous chemicals and defective products.

Implementation Method 1

0.7 to 0.9 parts by weight of a peroxide cross-linking agent

Methodology Applied
Scientific EffectPeroxide cross-linking: Oxidation

Implementation Method 2

a thermoplastic elastomer composition including: 80 to 90 parts by weight of an ethylene propylene diene monomer (EPDM); 30 to 50 parts by weight of polybutene (PB); 30 to 40 parts by weight of polypropylene (PP)

Methodology Applied
Scientific EffectPhase separation: Phase Change

Data Source

PatentUS8853316B2Thermoplastic elastomer composition
Publication Date: 2014.10.07 HYUNDAI MOTOR CO LTD

AI summary

A thermoplastic elastomer composition, and more particularly, a thermoplastic elastomer composition for use in manufacturing a joint connecting a glass run and an inner-belt. The thermoplastic elastomer composition includes an ethylene propylene diene monomer (EPDM), polybutene (PB), polypropylene (PP), paraffin oil, a peroxide cross-linking agent, and an antioxidant.