Thermally Expandable Polysaccharide Compositions for Automotive Sealing

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Solution Overview

Problem

Existing thermally expandable compositions used in the automotive sector face issues with respiratory sensitization, toxicity, explosiveness, and poor storage stability due to the use of exothermic blowing agents, which also affect the foam structure and water absorption.

Innovation Solution

A thermally expandable composition containing peroxide-crosslinking polymer, peroxide, polysaccharides such as starch, and endothermic chemical blowing agents, with less than 1% by weight of exothermic blowing agents, improving expansion and storage stability while reducing harmful by-products and water absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If exothermic blowing agents are used in thermally expandable compositions, then expansion capability is achieved, but respiratory sensitization, toxicity, and explosiveness occur

Engineering Contradiction:

Improveexpansion capabilityVSAvoidrespiratory sensitization and toxicity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameter of the blowing agent from exothermic to endothermic type. This parameter change eliminates the harmful effects (respiratory sensitization, toxicity, explosiveness) while preserving the expansion capability through a different chemical mechanism that operates at lower temperatures

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful exothermic decomposition into a beneficial endothermic process. The endothermic blowing agents absorb heat during decomposition, providing expansion capability while eliminating the harmful by-products and safety risks associated with exothermic agents

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If exothermic blowing agents are used, then expansion occurs, but harmful by-products such as ammonia, formaldehyde, and nitrosamines are produced

Engineering Contradiction:

ImproveexpansionVSAvoidharmful by-products

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the decomposition temperature parameter and reaction type from exothermic to endothermic. This parameter change fundamentally alters the decomposition pathway to produce only water and carbon dioxide, eliminating harmful by-products like ammonia, formaldehyde, and nitrosamines

Inventive Principle:

Principle #35Parameter changes

3Productivity

If exothermic blowing agents are used, then expansion is achieved, but VOC content becomes very high

Engineering Contradiction:

ImproveexpansionVSAvoidVOC content

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the decomposition characteristics from exothermic to endothermic, which fundamentally alters the chemical reaction pathway. This parameter change results in decomposition that produces only water and carbon dioxide, eliminating volatile organic compounds entirely

Inventive Principle:

Principle #35Parameter changes

4Object-generated harmful factors

If endothermic blowing agents are used, then harmful by-products are reduced, but storage stability deteriorates under high humidity

Engineering Contradiction:

Improveharmful by-productsVSAvoidstorage stability

Core Design Contradiction:

Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent introduces silane-modified polymers as intermediary substances that act as protective agents. These modifiers form a protective barrier around the endothermic blowing agents, preventing their premature reaction with moisture during storage while allowing normal expansion function when activated by heat

Inventive Principle:

Principle #24Intermediary (Mediator)

5Adaptability or versatility

If curing temperature is varied, then process flexibility is improved, but foam structure and water absorption fluctuate greatly

Engineering Contradiction:

Improveprocess flexibilityVSAvoidfoam structure consistency

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent changes the decomposition mechanism from exothermic to endothermic, which fundamentally alters the temperature-response characteristics. Endothermic agents provide a more gradual and consistent decomposition profile across varying temperatures, resulting in stable foam structure and reduced water absorption fluctuations

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 composition achieves excellent expansion and storage stability, reduces harmful by-products, and lowers water absorption, making it suitable for sealing and reinforcing components in vehicles without the drawbacks of traditional exothermic agents.

Implementation Method 1

at least one endothermic chemical blowing agent

Methodology Applied

Scientific EffectEndothermic decomposition: Endothermic Reaction

Implementation Method 2

thermally expandable composition

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

at least one peroxide-crosslinking polymer, at least one peroxide

Methodology Applied

Scientific EffectPeroxide crosslinking: Oxidation

Data Source

PatentEP3147323B2Thermally expandable compositions with polysaccharide

Publication Date: 2022.12.28 HENKEL KGAA

AI summary

The present application relates to a thermally expandable composition comprising at least one peroxide-crosslinking polymer, at least one peroxide, at least one polysaccharide and at least one endothermic chemical blowing agent, molded bodies containing this composition, and a method for sealing and filling cavities in components, for reinforcing or stiffening components, in particular hollow components, and for bonding movable components using such molded bodies.