Sealing Tape Adhesive Layer Arrangement for Vapor Diffusion

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Solution Overview

Problem

Existing sealing tapes face challenges in providing reliable bonding to various materials while maintaining optimal vapor diffusion resistance, especially with humidity-dependent barrier layers, as the adhesive layer can act as a barrier to water vapor transmission and may not adhere well to rough surfaces, particularly in wet conditions.

Innovation Solution

A sealing tape design featuring a barrier layer with a continuous adhesive layer on its sides and a partially covered adhesive layer in the center, allowing for adjustable adhesive thickness and composition to optimize bonding without significantly affecting vapor diffusion resistance, and incorporating a moisture-variable diffusion resistance barrier layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a continuous adhesive layer is applied on the barrier layer, then bonding reliability to rough surfaces is improved, but water vapor diffusion resistance increases

Engineering Contradiction:
Improvebonding reliabilityVSAvoidwater vapor diffusion resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesive layer is segmented into discrete adhesive points or stripes rather than a continuous layer. This segmentation creates adhesive-free channels that allow water vapor to pass through while maintaining sufficient bonding areas to adhere to rough surfaces, thus resolving the contradiction between bonding reliability and vapor transmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the barrier layer are assigned different adhesive coverage: edge regions have continuous adhesive layers for reliable bonding to frame surfaces, while the central region has reduced or discontinuous adhesive coverage to maintain vapor diffusion pathways. This local differentiation resolves the contradiction by optimizing each region for its specific function.

Inventive Principle:
Principle #3Local quality

2Strength

If adhesive layer thickness is increased to improve bonding to rough surfaces, then adhesion strength is improved, but vapor diffusion resistance increases

Engineering Contradiction:
Improveadhesion strengthVSAvoidvapor diffusion resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The adhesive is applied in segmented form (discrete points or stripes) rather than a continuous thick layer. This allows sufficient adhesive material at bonding locations to achieve strong adhesion to rough surfaces, while the spaces between adhesive segments provide channels for vapor diffusion, thus resolving the contradiction between adhesion strength and vapor transmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive layer parameters are changed from continuous and uniform to discontinuous and variable. By controlling the distribution, thickness, and coverage area of adhesive in different regions, the solution achieves adequate bonding strength where needed while maintaining vapor diffusion pathways, thus resolving the contradiction.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a barrier layer with high Sd-value is used to prevent moisture transmission, then moisture protection is improved, but controlled transmission of excess moisture is reduced

Engineering Contradiction:
Improvemoisture protectionVSAvoidcontrolled transmission of excess moisture
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The adhesive-free channels in the central region act as intermediaries that allow controlled moisture transmission. While the barrier layer material itself provides high Sd-value for moisture protection, the adhesive-free channels provide pathways for excess moisture to escape, thus resolving the contradiction between moisture protection and controlled transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Different regions of the sealing tape have different permeability characteristics: edge regions with continuous adhesive provide moisture protection and bonding, while the central region with adhesive-free channels provides controlled moisture transmission. This local differentiation resolves the contradiction by allowing both functions to coexist in different locations.

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

This design enhances bonding to diverse materials while maintaining effective water vapor transmission, reducing production costs and preventing water vapor seepage through adhesive-free channels, particularly suitable for sealing joints between window frames and wall openings.

Implementation Method 1

a barrier layer and a layer of adhesive applied on one surface of the barrier layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the vapor permeability of a layer is usually expressed as water vapor diffusion equivalent air layer thickness value (Sd-value). The Sd-value depends on the water vapor diffusion resistance and thickness of the layer

Methodology Applied
Scientific EffectWater vapor diffusion: Diffusion

Data Source

PatentEP3330470B1Sealing tape with adhesive layer arrangement
Publication Date: 2022.06.01 SIKA TECH AG
  • EP3330470B1 patent drawingFigure 1
  • EP3330470B1 patent drawingFigure 2
  • EP3330470B1 patent drawingFigure 3

AI summary

The invention is directed to a sealing tape used for sealing joints and gaps between building constructions, especially between window frames and door frames and corresponding edges of the respective wall openings. The sealing tape comprises a barrier layer (1) and a layer of adhesive (2) applied on one of the sides of the barrier layer, which layer of adhesive (2) is applied in a different pattern in various sections of the barrier layer. In the side sections (B1, B2) near the edges (e1, e2) of the barrier layer, the layer of adhesive (2) is applied as a continuous solid layer whereas in the central section (A), the surface of the barrier layer (1) is only partially covered by the layer of adhesive.