Sprayable Plastisol Damping Coating for Automotive Fogging Reduction

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Solution Overview

Problem

Existing vibration damping materials for automotive applications, such as bitumen mats and previous plastisol formulations, face challenges including logistical issues, quality fluctuations, toxicity concerns, and fogging problems due to volatile components, which hinder their widespread adoption and effectiveness.

Innovation Solution

A plastisol formulation comprising 1-60% oligomers with a molecular weight less than 20,000 g/mol, 0-60% solvents, 5-60% powdered polymers with over 60% (meth)acrylates, and additional fillers, auxiliaries, and additives, which reduces fogging and enhances processability and damping properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bitumen mats are used for vibration damping, then damping effectiveness is improved, but logistics complexity and manual labor increase

Engineering Contradiction:
Improvedamping effectivenessVSAvoidlogistics complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical bitumen mat system with a sprayable plastisol composition that can be automatically applied. The plastisol formulation with specific oligomers and powdered polymers enables robotized spray application, eliminating the need for manual handling and storage of pre-cut bitumen mats while maintaining vibration damping effectiveness.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If bitumen mats are glued on manually, then application is simple, but quality consistency deteriorates

Engineering Contradiction:
Improveapplication simplicityVSAvoidquality consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces manual gluing operations with automated spray application of plastisol composition. The sprayable formulation allows for consistent, controlled application through robotic systems, eliminating human variability in application quality while maintaining process simplicity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If PVC or chlorinated thermoplastics are used, then processability is improved, but ecological harm increases

Engineering Contradiction:
ImproveprocessabilityVSAvoidecological harm
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing chlorine-containing plastics with a plastisol formulation based on (meth)acrylate oligomers and powdered polymers. This substitution maintains processability through the oligomer-solvent-polymer system while eliminating the generation of HCl and dioxins during combustion, resolving the ecological harm issue.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If hot processing is applied to compositions, then damping properties are improved, but energy consumption and complexity increase

Engineering Contradiction:
Improvedamping propertiesVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the processing parameters by developing a plastisol composition that cures at lower temperatures through its oligomer-polymer-solvent system. The formulation achieves adequate damping properties without requiring high-temperature hot processing, thereby reducing energy consumption and process complexity.

Inventive Principle:
Principle #35Parameter changes

5Reliability

If aqueous dispersions are used for thicker layers, then damping effectiveness is improved, but drying time increases

Engineering Contradiction:
Improvedamping effectivenessVSAvoiddrying time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the solvent system parameters by using a plastisol formulation with controlled volatility. The composition achieves adequate damping with reduced layer thickness and provides optimized drying characteristics through the specific oligomer-solvent-polymer balance, reducing drying time compared to aqueous dispersions.

Inventive Principle:
Principle #35Parameter changes

6Ease of manufacture

If (meth)acrylate plastisols with high plasticizer content are used, then processability is improved, but fogging increases

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

Solution Approach 1:

The patent changes the composition parameters by optimizing the plasticizer content and selecting specific oligomers with appropriate molecular weights and (meth)acrylate content. This formulation maintains adequate processability while minimizing volatile component evaporation, thereby reducing fogging on vehicle windows.

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 formulation improves damping properties, reduces fogging, and allows for flexible application on complex surfaces, optimizing storage and quality while minimizing environmental concerns.

Implementation Method 1

It has been found that by replacing all or part of the plasticizer commonly used in plastisols with oligomers, particularly (meth)acrylate oligomers, 'fogging' can be reduced.

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

In the case of thicker layers, which are necessary for a good damping effect, however, long drying times are necessary in order to remove the water from the sprayed layer.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP1940947B1Sprayable acoustic compositions
Publication Date: 2009.10.07 ROHM GMBH

AI summary

The invention relates to sprayable acoustic compositions, production methods and uses.