Polyvinyl Acetate Dispersion Storage Stability via Silicate Incorporation

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Solution Overview

Problem

Aqueous polymer dispersions containing pigments and fillers are not storage-stable due to sedimentation and the formation of dissolved metal ions, leading to reduced stability and adhesive performance, especially under humid conditions.

Innovation Solution

Polymerization of vinyl ester monomers in the presence of a hydrophobic ethylene/vinyl alcohol copolymer and layered silicates as a filler, which are incorporated during the polymerization process to create a stable adhesive dispersion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fillers are added to aqueous polymer dispersions, then adhesive performance and barrier effect are improved, but storage stability deteriorates due to sedimentation and formation of dissolved metal ions

Engineering Contradiction:
Improveadhesive performanceVSAvoidstorage stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by incorporating fillers during the polymerization process rather than adding them afterward. This ensures that fillers are uniformly distributed and stabilized within the polymer matrix from the beginning, preventing subsequent sedimentation and maintaining storage stability while achieving the desired adhesive performance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a specific polyvinyl alcohol as an intermediary substance that mediates between the fillers and the polymer matrix. This polyvinyl alcohol acts as a stabilizing agent that prevents filler aggregation and sedimentation, allowing the dispersion to maintain both adhesive performance and storage stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If pigments and fillers are incorporated into the dispersion, then application-related advantages such as barrier effect and adhesive strength are achieved, but dispersion stability deteriorates due to rapid sedimentation

Engineering Contradiction:
Improveapplication-related advantagesVSAvoiddispersion stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent merges the incorporation of pigments and fillers with the polymerization process itself. By combining these operations, the fillers and pigments are integrated into the polymer structure during formation, creating a homogeneous composite material that maintains stability while providing the desired application advantages.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies parameter changes by controlling the polymerization conditions (temperature, concentration, timing) to optimize the incorporation of pigments and fillers. By adjusting these parameters, the dispersion maintains stability while achieving the required barrier effect and adhesive strength.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If fillers are added during adhesive formulation preparation, then desired filler effects are achieved, but uniform dispersion and stability are difficult to maintain

Engineering Contradiction:
Improvefiller contentVSAvoiduniform dispersion
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by incorporating fillers during the polymerization process rather than adding them afterward. This ensures that fillers are uniformly distributed and stabilized within the polymer matrix from the beginning, preventing subsequent aggregation and maintaining manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

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 resulting adhesive dispersion is storage-stable with improved shelf life and mechanical properties, maintaining bond resilience even in damp environments.

Implementation Method 1

vinyl ester monomers are polymerized in the presence of a specific filler and a selected polyvinyl alcohol as a protective colloid

Methodology Applied
Scientific EffectPolymerization:

Implementation Method 2

a hydrophobic ethylene/vinyl alcohol copolymer and layered silicates as a filler, which are incorporated during the polymerization process to create a stable adhesive dispersion

Methodology Applied
Scientific EffectProtective colloid stabilization: Colloid

Data Source

PatentEP2931823B1Method for producing a polyvinyl acetate dispersion
Publication Date: 2019.04.17 HENKEL KGAA

AI summary

A method for producing an aqueous adhesive dispersion, wherein a dispersion is produced from a sheet silicate having an SiO2 fraction and a hydrophobic ethylene/polyvinyl alcohol copolymer as protective colloid, and, in the presence of this dispersion, vinyl esters and optionally comonomers are polymerized.