Cross-linked Polysiloxane Barrier Coating for Silicone Compatibility

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Solution Overview

Problem

Current air and water barrier coatings in the construction industry face compatibility issues with silicone-based materials, leading to increased costs and complexity due to poor UV stability and compatibility problems, as well as the need for additional layers and labor, especially when used in conjunction with organic-based coatings.

Innovation Solution

A cross-linked polysiloxane dispersion composition is used as a liquid-applied, vapour permeable air and water barrier coating, comprising a reaction product of siloxane polymers with -OH groups, self-catalyzing crosslinkers, surfactants, and fillers, which meets specific ASTM standards for air permeance and water vapour transmission, and is compatible with silicone-based products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If organic-based air and water barrier coatings are used, then vapour permeability and air leakage control are improved, but compatibility with silicone-based materials deteriorates and additional layers are required

Engineering Contradiction:

Improvevapour permeability controlVSAvoidnumber of additional layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the air and water barrier function with silicone-based material compatibility into a single coating system. The polysiloxane dispersion formulation integrates vapour permeability control with chemical compatibility, eliminating the need for separate compatibility layers or primers that would otherwise be required when using organic-based coatings with silicone materials.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The polysiloxane dispersion coating serves multiple functions simultaneously: it provides vapour permeability control, ensures compatibility with silicone-based sealants and adhesives, and acts as an effective air and water barrier. This multi-functional approach replaces the need for multiple specialized layers required by conventional organic-based coating systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If organic-based air and water barrier coatings are used, then barrier performance is improved, but UV stability deteriorates and re-application is required

Engineering Contradiction:

Improveair and water barrier performanceVSAvoidUV exposure durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters from organic-based to polysiloxane-based formulation. This parameter change fundamentally alters the material's UV resistance properties while maintaining the air and water barrier performance, allowing the coating to withstand prolonged UV exposure without degradation or re-application.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If organic-based air and water barrier coatings are used, then vapour permeability control is improved, but compatibility with silicone sealants deteriorates and additional adhesives are required

Engineering Contradiction:

Improvevapour permeability controlVSAvoidapplication process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The polysiloxane dispersion coating merges vapour permeability control with chemical compatibility for silicone sealants into a single integrated system. This eliminates the need for additional adhesives or primers that would otherwise be required to ensure proper bonding between the organic-based coating and silicone-based sealing materials.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If vapour impermeable coatings are used, then air leakage control is improved, but moisture accumulation risk increases

Engineering Contradiction:

Improveair leakage controlVSAvoidmoisture accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by providing different permeability characteristics for different substances: the coating maintains low air permeability to control air leakage while simultaneously maintaining high vapour permeability to allow moisture vapour transmission. This selective permeability prevents moisture accumulation while effectively controlling air infiltration.

Inventive Principle:

Principle #3Local quality

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 cross-linked polysiloxane dispersion composition provides a cost-effective, labour-efficient, and UV-stable vapour permeable air and water barrier that meets stringent ASTM standards, ensuring effective moisture management and compatibility with silicone-based materials, reducing the need for additional layers and simplifying the construction process.

Implementation Method 1

This type of air and water barrier is designed to allow moisture vapour to pass through the membrane, promoting diffusion. Unless prevented or controlled, water vapour will naturally move from a high concentration to a lower concentration until it is in balance.

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

The liquid-applied materials are applied and dry or cure as a monolithic membrane around the building envelope.

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2943544B1Air and water barrier

Publication Date: 2023.09.20 DOW SILICONES CORP

AI summary

A method for decreasing the vapour permeability of a water and air barrier treated substrate that includes treating the substrate with a liquid applied, vapour permeable air and water barrier coating composition comprising a cross-linked polysiloxane dispersion composition.