Reinforced Microporous Polyolefin Roofing Membrane
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microporous polypropylene copolymer films lack the mechanical properties and performance characteristics required for roofing membranes, particularly in terms of strength, elongation, and weldability, making them unsuitable for use in continuous, leak-free water barriers.
Innovation Solution
A method involving extrusion lamination of a non-porous polyolefin sheet onto a non-woven fabric, followed by sequential cold and hot stretching steps, creates a reinforced microporous polyolefin sheet with a phase-segregated polymer composition that includes a polypropylene homopolymer continuous phase and ethylene-propylene copolymer dispersed phase, ensuring excellent breathability and liquid barrier properties without defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microporous polypropylene copolymer films are produced by stretching, then breathability is improved, but mechanical properties and performance characteristics deteriorate
Solution Approach 1:
The patent applies composite materials by combining microporous polypropylene copolymer film with a reinforcement layer (such as woven or non-woven fabric) to create a laminated structure. This composite construction allows the microporous film to provide breathability while the reinforcement layer supplies the necessary mechanical strength and durability for roofing membrane applications.
2Reliability
If microporous polypropylene copolymer films are produced by stretching, then breathability is improved, but weldability deteriorates
Solution Approach 1:
The patent applies local quality by creating a laminated structure where different layers serve different functions: the microporous polypropylene copolymer film layer provides breathability, while the adjacent reinforcement layer or interface regions are designed to maintain good thermal welding properties. This allows localized optimization where weldability is preserved at the laminate interfaces even though the microporous film itself has reduced weldability.
3Strength
If polyolefin sheet is laminated onto non-woven fabric, then mechanical strength is improved, but micropore formation during stretching becomes difficult
Solution Approach 1:
The patent applies preliminary action by first forming the non-porous laminate structure through extrusion lamination of polyolefin sheet onto non-woven fabric, and then subsequently applying stretching treatment to this pre-formed laminate. This sequence allows the laminate structure to be established before micropores are created, enabling both reinforcement and breathability to be achieved in a controlled manufacturing process.
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 reinforced microporous sheet exhibits high breathability, effective liquid water barrier, and mechanical strength, suitable for roofing membranes, with improved weldability and resistance to tearing.
Implementation Method 1
a phase-segregated polymer composition that includes a polypropylene homopolymer continuous phase and ethylene-propylene copolymer dispersed phase
Implementation Method 2
subjecting the non-porous laminate to sequential stretching steps to produce micropores in the polyolefin
Implementation Method 3
extrusion laminating a non-porous sheet of a polyolefin onto at least one side of a non-woven fabric
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Reinforced microporous polyolefin sheets comprise one or more layers of a microporous polyolefin and a non-woven fabric at least partially embedded in the microporous polyolefin. The reinforced microporous polyolefin sheet is made in an extrusion lamination process by which a polyolefin sheet and non-woven fabric are laminated, followed by sequential cold and hot stretching steps to produce the micropores.