Elastomer Layer Composition for Fire-Safe Air Spring Bellows

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Solution Overview

Problem

Articles with elastomeric mixtures, such as air spring bellows and vibration dampers, fail to meet stringent fire protection requirements due to high heat release rates and toxic smoke production during combustion, and traditional flame-retardant additives compromise their physical properties.

Innovation Solution

A single-layer or multi-layer article with a rubber mixture containing halogen-free flame retardants and specific carbon blacks with high BET surface area and oil absorption number, combined with additional flame retardants like zinc stannate, to enhance fire protection while maintaining dynamic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional flame-retardant substances are added to rubber mixtures, then fire protection behavior is improved, but physical properties such as hardness and dynamic characteristics deteriorate

Engineering Contradiction:
Improvefire protection behaviorVSAvoidphysical properties
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention changes the parameters of carbon black (BET surface area between 35-140 m²/g and OAN between 70-140 ml/100g) to achieve optimal fire protection while maintaining physical properties. This parameter optimization allows the rubber mixture to meet fire safety requirements without compromising hardness and dynamic characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite approach by combining specific carbon black with halogen-free flame retardants in a rubber mixture. This composite formulation achieves synergistic effects where the carbon black provides fire protection and reinforcement, while the halogen-free flame retardants contribute to fire safety without the negative effects of traditional halogenated compounds.

Inventive Principle:
Principle #40Composite materials

2Temperature

If chloroprene rubber is used for weather and heat resistance, then mineral oil and heat resistance is improved, but smoke toxicity during combustion increases

Engineering Contradiction:
Improveheat resistanceVSAvoidsmoke toxicity
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The invention modifies the chemical composition parameters by using halogen-free flame retardants instead of traditional halogenated compounds. This substitution maintains the heat resistance properties of chloroprene rubber while significantly reducing the toxicity of smoke generated during combustion, thereby resolving the contradiction between heat resistance and smoke safety.

Inventive Principle:
Principle #35Parameter changes

3Strength

If natural rubber or polyisoprene rubber is used for elastic properties, then elastic characteristics are improved, but heat release rate during combustion increases

Engineering Contradiction:
Improveelastic propertiesVSAvoidheat release rate
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention creates a composite rubber mixture that combines natural rubber or polyisoprene rubber with specific carbon black and halogen-free flame retardants. This composite formulation maintains the excellent elastic properties of the base rubber while the carbon black and flame retardants work synergistically to reduce the heat release rate during combustion.

Inventive Principle:
Principle #40Composite materials

4Reliability

If additional flame retardants are reduced, then dynamic suitability and service life are improved, but fire protection behavior may deteriorate

Engineering Contradiction:
Improvedynamic suitabilityVSAvoidfire protection behavior
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the parameters of carbon black (BET surface area and OAN) to achieve maximum fire protection efficiency. By precisely controlling these parameters, the invention reduces the required amount of additional flame retardants while maintaining adequate fire protection behavior, thereby improving dynamic suitability and service life.

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 significantly reduces additional flame retardant usage, improving the article's service life and dynamic suitability while meeting stringent fire protection standards like EN45545, particularly reducing smoke toxicity and maintaining physical properties.

Implementation Method 1

at least one carbon black with a BET surface area according to DIN-ISO 9277 between 35 and 140 m2/g and an oil absorption number (OAN) according to ISO 4656 between 70 and 140 ml/100g

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3728455B1Article, in particular air spring bellows, a metal-rubber element, or a vibration damper
Publication Date: 2022.08.17 CONTITECH LUFTEDERSYSTEME GMBH

AI summary

The invention relates to an article comprising a single or multi-layer main body having elastic properties, in particular air spring bellows, a metal-rubber element or a vibration damper. In order to improve the flame-retarding properties, the main body of the article consists of or contains at least one layer D formed of a rubber mixture that is free from halogen-containing flame retardant means and contains at least one carbon black with a BET surface area of between 35 and 140 m2/g (according to DIN-ISO 9277) and with an oil absorption number (OAN) of between 70 and 140 ml /100g (according to ISO 4656).