Flexible Cementitious Membrane Composite for Crack Isolation
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Solution Overview
Problem
Traditional underlayment systems for ceramic tiles are prone to cracking and damage due to the expansion and contraction of wood or drywall substrates, leading to propagation of cracks from the subfloor to the finish floor, and existing solutions like cement board are heavy, labor-intensive, and not waterproof.
Innovation Solution
A flexible membrane with a basemat composed of multiple plies of spunbond and meltblown polymers, coated with a hydraulic cementitious slurry containing high fly ash, and attached to the subfloor using a deformable adhesive, which absorbs lateral forces and reduces crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cement board is used as underlayment, then strength and rigidity are improved, but weight increases significantly
Solution Approach 1:
The patent uses a composite underlayment system combining organic fiber mat, inorganic filler, polymer binder, and waterproofing agents to achieve both strength and light weight. This composite structure replaces traditional heavy cement board while maintaining structural integrity through synergistic material combinations.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the underlayment materials, including polymer content (5-20%), fiber mat density, and binder composition, to optimize the strength-to-weight ratio. These parameter adjustments enable reduced weight while preserving necessary mechanical properties.
2Weight of stationary object
If plastic sheeting is used as underlayment, then weight is reduced, but bonding surface quality deteriorates
Solution Approach 1:
The patent creates a composite underlayment with a specially engineered bonding surface that combines organic fibers, inorganic fillers, and polymer binders. This surface provides optimal adhesion properties for thin-set mortar while maintaining the lightweight advantage of plastic sheeting, eliminating the bonding problems of pure plastic membranes.
Solution Approach 2:
The underlayment structure is designed with different local properties: the bonding surface contains enhanced filler and binder concentration for optimal mortar adhesion, while the core remains lightweight and flexible. This localized quality differentiation solves the bonding surface problem without compromising overall light weight.
3Stability of the object's composition
If rigid construction is used for floor system, then structural stability is improved, but crack propagation resistance deteriorates
Solution Approach 1:
The patent introduces dynamic flexibility into the floor system through the elastic polymer-modified underlayment that can deform and absorb stress. This dynamic response allows the system to accommodate substrate movement without rigid failure, preventing crack propagation while maintaining overall structural stability.
Solution Approach 2:
The patent changes the mechanical parameters of the underlayment by incorporating polymer modifiers that increase elongation and flexibility. These parameter changes enable the underlayment to transition from rigid to semi-flexible behavior, allowing it to bridge cracks and prevent their propagation through the finished floor.
4Reliability
If thin hydraulic layer is used on basemat, then waterproofing is improved, but flexibility deteriorates
Solution Approach 1:
The patent develops a composite membrane structure where a thin hydraulic cement layer is integrated with a flexible polymer-modified basemat. The polymer binder and fiber reinforcement in the basemat maintain flexibility even with the thin hydraulic coating, enabling both waterproofing and adaptability to substrate movement.
Solution Approach 2:
The patent uses a flexible polymer-modified basemat as the substrate for the thin hydraulic layer. This flexible base allows the thin waterproofing layer to conform and move with substrate deformation, maintaining both waterproofing integrity and system flexibility that would be impossible with rigid cement board.
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 system effectively isolates cracks, reducing damage to the finish floor by stretching and deforming with the subfloor, providing excellent moisture resistance and durability, and requiring less maintenance with reduced likelihood of tile breakage and regrouting.
Implementation Method 1
The spunbond layers hold the slurry, which binds the fibers in those layers into a crystalline matrix as the hydraulic material hydrates.
Implementation Method 2
The adhesive may be deformable... which absorbs lateral forces and reduces crack propagation
Data Source
AI summary
In a preferred embodiment, a floor crack isolation system includes a membrane and a deformable adhesive. The membrane includes a basemat, having at least three plies, a ply of a meltblown polymer sandwiched between two plies of spunbond polymer; and a flexible coating applied to the basemat, the coating having a cementitious hydraulic component, a polymer comprising a water-soluble, film-forming polymer; and water. The finished membrane is flexible and is bonded to a subfloor with a deformable adhesive. A method of making the floor crack isolation system includes obtaining a coated, three-ply, flexible membrane and applying it to a subfloor with a deformable adhesive.