Breathable Roofing Laminate UV Protection via TPU Coating
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Solution Overview
Problem
Existing breathable underlays in building construction face issues with aging, which affects their effectiveness over time, particularly in terms of UV resistance and mechanical properties.
Innovation Solution
A breathable underlay comprising a water-permeable and vapour-permeable fabric carrier layer with a water-impermeable and vapour-permeable active layer, coated with a thermoplastic polyurethane layer that enhances mechanical properties, UV resistance, and maintains breathability for a longer duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a breathable underlay is used in building construction, then vapour permeability is achieved, but UV resistance and mechanical properties deteriorate over time due to aging
Solution Approach 1:
A coating layer made of thermoplastic polyurethane, polyether polyamide block copolymer, or polyether-ester is applied to the carrier layer to serve as a protective intermediary. This coating layer specifically protects against UV radiation and mechanical damage while allowing vapour to pass through, thus protecting the breathable underlay from environmental degradation without compromising its vapour permeability function.
Solution Approach 2:
The underlay combines multiple materials with complementary properties: a water-permeable and vapour-permeable carrier layer (fabric) provides breathability, while a water-impermeable and vapour-permeable active layer provides waterproofing. The additional coating layer of thermoplastic polyurethane or similar materials adds UV resistance and mechanical strength, creating a composite structure that integrates multiple functions.
2Strength
If the carrier layer is coated with a protective layer to enhance mechanical properties and UV resistance, then reliability is improved, but vapour permeability may be reduced
Solution Approach 1:
The coating layer is designed to be porous or microporous, allowing water vapour molecules to pass through while providing mechanical protection and UV resistance. The porous structure maintains the breathability function of the carrier layer while the coating material provides the necessary protective properties against environmental factors.
Solution Approach 2:
The coating layer is applied selectively to specific regions or surfaces of the carrier layer where UV exposure and mechanical stress are most critical. This localized protection ensures that the coating provides maximum benefit where needed while minimizing any potential impact on overall vapour permeability.
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 solution provides a breathable underlay with improved mechanical strength, water tightness, high vapour permeability, and extended service life, retaining breathability and functionality over time while resisting UV radiation and environmental loading.
Implementation Method 1
a water-impermeable and vapour-permeable active layer, coated with a thermoplastic polyurethane layer that enhances mechanical properties, UV resistance
Implementation Method 2
which carrier layer is water-permeable and vapour-permeable and a water-impermeable and vapour-permeable active layer
Implementation Method 3
The barrier layer is made of TPE-U (hydrophilic thermoplastic polyurethane), TPE-A (hydrophilic polyether polyamide block copolymer) or TPE-E (hydrophilic polyetherester)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to breathable coated underlays or laminates used in building construction. According to the invention the underlay comprises at least three layers, i.e. a carrier layer (12) that is water-permeable and vapour-permeable, an active layer (10) that is water-impermeable and vapour-permeable and a coating layer (14) that is water-permeable and vapour-permeable. The coating layer is made at least partially from one of the following a) thermoplastic polyurethane, b) polyether polyamide block copolymer or c) polyether-ester, preferably from aromatic or non-aromatic thermoplastic polyurethane, i.e. TPU. The underlay (20) may have an active layer (10) between two carrier layers (12).