Substrate for a support for bituminous membrane and method for the preparation thereof
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Solution Overview
Problem
Existing substrates for bituminous membranes face challenges in achieving high mechanical strength, dimensional stability, and fire resistance while minimizing weight and material usage, with previous methods requiring expensive processes and high fiber lengths, which can compromise mechanical strength and fire resistance.
Innovation Solution
A substrate comprising layers of organic and inorganic staple fibers, mixed through repeated opening and blending during carding, with a reinforcing scrim interposed between the layers, consolidated via hydroentangling and heat setting, reducing the need for binders and optimizing fiber distribution for improved mechanical and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the mass of the non-woven fabric is increased to meet transversal tensile strength requirements, then the mechanical strength in transversal direction is improved, but the weight of the substrate increases
Solution Approach 1:
The patent applies composite materials by combining organic fibers (polyester, polypropylene) with inorganic fibers (glass fibers) in a non-woven fabric structure. This composite approach allows the substrate to achieve high transversal tensile strength through the reinforcement provided by glass fibers and the structural interlocking, while maintaining lower overall weight compared to using solely heavy organic fibers or increasing fabric mass. The synergistic effect of different fiber types enables meeting mechanical requirements without proportionally increasing weight.
2Strength
If expensive technological choices such as carding machines arranged in transversal direction and pre-needling machines are used to comply with mechanical features, then the transversal mechanical strength is improved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the fundamental parameters of the substrate composition by incorporating inorganic fibers (glass fibers) with specific properties (high tensile strength, dimensional stability) into the non-woven fabric. This parameter change in material composition allows achieving the required transversal mechanical strength through the intrinsic properties of the fiber mixture and the hydroentangling consolidation process, rather than relying on expensive post-processing equipment like transverse carding machines or pre-needling machines. The solution shifts from process-intensive to material-intensive approach.
3Object-affected harmful factors
If conventional wet processing methods are used with water dispersions of glass fibers, then the fire resistance is improved, but the mechanical strength decreases due to low fiber length and limited adhesion points
Solution Approach 1:
The patent replaces the conventional wet processing mechanical system (water dispersion, suction mat distribution) with a dry processing system using carding machines. This substitution allows fibers to be handled in dry state, maintaining their full length and structural integrity. The carding process mechanically interlocks fibers through comb-like teeth, creating numerous adhesion points and a cohesive fabric structure. This mechanical carding action, rather than wet dispersion, provides both the fire resistance (through proper fiber composition including fire-resistant glass fibers) and the mechanical strength (through extensive fiber-to-fiber contact and interlocking).
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 achieves a high weight-to-performance ratio with enhanced mechanical strength, dimensional stability, and fire resistance, while reducing material usage and environmental impact, and facilitating recyclability of bituminous membranes.
Implementation Method 1
the layers-scrim 3, 4 complex is then consolidated by means of hydroentangling
Implementation Method 2
dried, thermally stabilized
Data Source
AI summary
A substrate for a support for bituminous membranes, comprising two or more layers of fibers comprising a homogeneous mixture of organic fibers and inorganic fibers, between which there is interposed a reinforcing scrim, said fibers being oriented parallel to the longitudinal axis of the substrate and laid said by side and alternate.