PVDC-Coated Glass Fiber Mesh for Low-Combustion ETICS
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Solution Overview
Problem
SBR-coated glass fiber mesh fabrics used in ETICS do not comply with Euroclass fire rating system requirements due to high gross heat of combustion, and attempts to reduce loss on ignition compromise mechanical strength, while PVDC coatings result in stiff products when used as a replacement.
Innovation Solution
A glass fiber mesh fabric coated with a mixture of poly(vinylidene chloride) (PVDC) and low amounts of heat-curable formaldehyde-based resins, along with a plastifying polymer, to achieve reduced stiffness and compliance with fire rating standards while maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If SBR rubber coating is used to provide mechanical strength and protection, then mechanical strength is improved, but gross heat of combustion increases to 7-8 MJ/kg
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by replacing SBR rubber with PVDC polymer, which has inherently lower combustibility. This parameter change reduces the gross heat of combustion from 7-8 MJ/kg to below 3 MJ/kg while maintaining protective functions through the new polymer's mechanical properties and adhesion characteristics.
Solution Approach 2:
The patent creates a composite coating system by combining PVDC polymer with inorganic additives such as antimony trioxide and magnesium hydroxide. This composite approach enhances fire resistance through synergistic effects where the inorganic compounds promote char formation and release water vapor during combustion, further reducing heat release while maintaining mechanical integrity.
2Object-generated harmful factors
If PVDC coating is used to reduce gross heat of combustion, then fire resistance is improved, but the product becomes too stiff to be rolled
Solution Approach 1:
The patent modifies the physical and chemical parameters of the PVDC coating by incorporating plasticizers and adjusting polymer molecular weight distribution. These parameter changes reduce the glass transition temperature and increase chain flexibility, enabling the coating to remain pliable and rollable while retaining its low combustibility characteristics.
Solution Approach 2:
The patent introduces plasticizing agents as intermediary substances that mediate between the rigid PVDC polymer structure and the desired flexibility. These intermediaries insert themselves between polymer chains, reducing intermolecular forces and enabling chain mobility, thus providing rollability without compromising fire resistance.
3Ease of operation
If LOI of PVDC-coated mesh is decreased to reduce stiffness and cost, then ease of operation is improved, but mechanical properties become low
Solution Approach 1:
The patent optimizes the cross-linking density parameter of the coating system by controlling the ratio of reactive groups and curing conditions. This parameter adjustment achieves moderate cross-linking that provides sufficient mechanical strength while leaving enough uncross-linked segments to maintain flexibility and reduce stiffness, avoiding the trade-off between strength and operability.
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 gross heat of combustion below 3.5 MJ/kg, meeting Euroclass fire rating standards while enhancing mechanical properties and reducing PVDC usage costs.
Implementation Method 1
Adding formaldehyde-based resins to the PVDC binder desirably increases the mechanical strength of the resulting coating
Implementation Method 2
a glass fiber mesh fabric coated with an organic polymer coating based on PVDC... To be classified in class A2... a glass fiber mesh fabric must have a gross heat of combustion (PCS)... of at most 3 MJ/kg
Data Source
AI summary
The invention is drawn to a glass fiber mesh fabric coated with an organic polymer coating having a reduced gross heat of combustion (less than 3.0 MJ/kg), said polymer coating comprising (i) from 60 wt% to 99.9 wt% of poly(vinylidene chloride) (PVDC) or a copolymer thereof; and (ii) from 0.1 wt% to 40 wt% of a formaldehyde-based resin selected from melamine-formaldehyde resins, phenol-formaldehyde resins, ureaformaldehyde resins or a combination thereof. The invention also provides a method for producing such a coated glass fiber mesh fabric.