Self-Adhering Roofing Membrane Without Migration Barrier
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Solution Overview
Problem
State-of-the-art self-adhering roofing membranes based on polyvinylchloride (PVC) have high production and installation costs due to the presence of a migration barrier, and require additional sealing methods for overlapping edges, increasing installation time and costs.
Innovation Solution
A self-adhering roofing membrane with a polyvinylchloride-based waterproofing layer and an acrylic pressure-sensitive adhesive layer, where the adhesive layer covers a significant portion of the waterproofing layer's surface without a migration barrier, allowing for adhesively bonded seams between overlapping edges using the same adhesive as for substrate bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a migration barrier is used between the waterproofing layer and adhesive layer in self-adhering roofing membranes, then plasticizer migration is prevented, but production costs increase
Solution Approach 1:
The patent removes the migration barrier layer from the membrane structure, extracting the problematic intermediate layer that caused both cost increases and adhesion failures. The solution relies on selecting an adhesive composition that is inherently resistant to plasticizer migration, eliminating the need for a separate barrier layer.
Solution Approach 2:
The patent changes the chemical composition parameters of the adhesive layer by selecting specific polymers (SBS, SIS, SBR) with appropriate molecular weights and glass transition temperatures, and by controlling plasticizer content and type. These parameter changes enable the adhesive to resist plasticizer migration without requiring a separate barrier layer.
2Reliability
If heat-welding or sealing tapes are used to seal overlapping edges, then waterproof sealing is achieved, but installation time and costs increase
Solution Approach 1:
The patent merges the adhesive function with the sealing function by applying the same acrylic pressure-sensitive adhesive composition to both the membrane surface for substrate bonding and the overlapping edges for seam sealing. This eliminates the need for separate heat-welding equipment or sealing tapes, reducing installation time and complexity.
Solution Approach 2:
The adhesive composition serves multiple functions: it bonds the membrane to the substrate, it seals overlapping edges to create waterproof seams, and it provides flexibility and adhesion. This multi-functional adhesive replaces what would traditionally require separate materials and processes for bonding and sealing.
3Reliability
If the adhesive layer covers the entire waterproofing layer surface, then full adhesion to substrate is achieved, but plasticizer migration into adhesive increases
Solution Approach 1:
The patent changes the chemical parameters of the adhesive composition by selecting acrylic polymers (SBS, SIS, SBR) with specific glass transition temperatures below 0°C and controlling the plasticizer content and type. These parameter changes make the adhesive chemically resistant to plasticizer migration while maintaining full-coverage adhesion.
Solution Approach 2:
The adhesive layer is formulated as a composite material containing a blend of acrylic polymers (SBS, SIS, SBR) with specific molecular weights and glass transition temperatures, along with carefully selected plasticizers. This composite structure provides both full-coverage adhesion and resistance to plasticizer migration from the PVC waterproofing layer.
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 configuration reduces production and installation costs while enabling fully-adhered roof systems with adhesively bonded seams, improving efficiency and reducing installation time.
Implementation Method 1
An adhesive layer (3) coated on and covering at least portion of the second major surface of the waterproofing layer (2)
Data Source
Figure 1~2
Figure 3
AI summary
The invention is directed to a roofing membrane (1) comprising a waterproofing layer (2), an adhesive layer (3), and optionally a release liner (4), wherein the adhesive layer (3) is an acrylic pressure sensitive adhesive layer. The invention is also directed to a fully-adhered roof system.