Plastisol Composition for Metal Sealing with Low-Temperature Curing

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Solution Overview

Problem

Existing plastisol compositions for sealing metal parts face challenges in achieving flexible, lightweight, easy-to-handle formulations with good aging properties and low curing temperatures, along with inadequate adhesion to metallic substrates and limited flexibility in production processes.

Innovation Solution

A plastisol composition comprising 20-40 wt% PVC-based polymer, 20-50 wt% plasticizers, and 0.5-5 wt% amino and/or amido-functional compounds or blocked polyurethanes, with a suspension-type PVC co-polymer containing 10-16% vinyl acetate units, which allows for low-temperature curing and enhanced adhesion to metal substrates, improved aging properties, and reduced density through the use of additives like microspheres.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional plastisol compositions are used for sealing metal parts, then good adhesion to metal substrates is achieved, but the compositions require high curing temperatures and have limited flexibility in production processes

Engineering Contradiction:
Improvecuring temperatureVSAvoidproduction process flexibility
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical composition parameters of the plastisol by incorporating specific reactive additives (aminoplasts, polyaminoamides, polyurethanes) in controlled amounts (0.1-5 wt%), which changes the curing mechanism to enable low-temperature curing (100-150°C) while maintaining adhesion to metal substrates

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite plastisol formulation combining PVC-based polymer (20-40 wt%), plasticizers (20-50 wt%), and multiple types of reactive additives (aminoplasts, polyaminoamides, polyurethanes) in specific proportions, which synergistically provide both low-temperature curability and good adhesion properties

Inventive Principle:
Principle #40Composite materials

2Reliability

If adhesion promoters are added to improve adhesion to metal substrates, then long-term adhesion is achieved, but the composition requires specific ester types which reduces production flexibility

Engineering Contradiction:
Improveadhesion to metal substrateVSAvoidproduction process flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses reactive additives that serve multiple functions simultaneously: they act as adhesion promoters for metal substrates, enable low-temperature curing, and provide crosslinking functionality. This multi-functionality eliminates the need for specific ester types while achieving reliable adhesion

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the approach from using specific ester types as adhesion promoters to using reactive additives (aminoplasts, polyaminoamides, polyurethanes) that provide adhesion through chemical bonding mechanisms, thereby expanding production flexibility while maintaining adhesion reliability

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional plastisol compositions are used, then good sealing properties are achieved, but the cured plastisol has high density which is not desirable for lightweight applications

Engineering Contradiction:
Improvesealing propertiesVSAvoiddensity of cured plastisol
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent modifies the plastisol composition by incorporating lightweight fillers and controlling the plasticizer-to-polymer ratio, which reduces the density of the cured plastisol while maintaining sealing properties through the crosslinking network formed by reactive additives

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 effective adhesion to metal substrates, improved aging properties, and reduced density, enabling flexible application and curing at temperatures between 120°C and 140°C, while maintaining mechanical integrity and reducing environmental impact.

Implementation Method 1

The plastisol compositions have the property to gel upon heating to higher temperature

Methodology Applied
Scientific EffectGelation: Gel

Implementation Method 2

amino and/or amido-functional compounds and/or blocked polyurethanes as reactive additives

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3696225B1Plastisol composition suitable for sealing of metal parts
Publication Date: 2021.11.10 EFTEC NV

AI summary

The invention relates to a plastisol composition suitable for sealing of metal parts comprising PVC, plasticizers, reactive additives based on amino and/or amido-functional compounds and/or blocked polyurethanes. The invention further relates to a process for producing plastisol compositions comprising the steps of a polymerizing vinyl chloride and co-monomers and combining them with plasticizers, amino and/or amido-functional compounds and/or blocked polyurethanes.