Flame-Resistant Carpet Back Coating With Lightweight Hot-Melt Adhesive
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Solution Overview
Problem
Current flame-retardant technologies for textile fabrics face challenges such as increased weight, complex application processes, high energy consumption, and limited recyclability, particularly due to the use of aqueous latex dispersions and polyurethane binders, which also lead to higher flammability and environmental concerns.
Innovation Solution
A 'ready-to-use' hot melt adhesive system based on polyolefinic homo- and copolymer waxes, combined with expandable graphite and conductive carbon black, which provides flame retardancy without solvents, reduces weight, and allows for easy recycling, while preventing the 'candle wick effect and improving antistatic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous latex dispersions or polyurethane binders are used for flame-retardant coating, then flame resistance is improved, but weight increases and recyclability decreases
Solution Approach 1:
The patent changes the binder system from heavy aqueous latex dispersions or polyurethanes to lightweight polyolefin hot melt adhesives. This parameter change in binder selection achieves flame resistance through the polyolefin matrix while significantly reducing coating weight compared to traditional binder systems.
Solution Approach 2:
The patent creates a composite flame-retardant system combining polyolefin hot melt adhesive with flame retardant additives (such as aluminum hydroxide, magnesium hydroxide, or phosphorus-based compounds). This composite approach provides both binding functionality and flame resistance while maintaining low weight.
2Weight of moving object
If polyolefin binders are used to reduce weight, then weight decreases, but flammability increases requiring higher flame retardant content
Solution Approach 1:
The patent converts the inherent flammability of polyolefin into a benefit by utilizing the polyolefin matrix to embed and deliver flame retardant additives effectively. The low melting point of polyolefin allows for easy incorporation of flame retardants that then protect the lightweight structure, turning the flammability weakness into an opportunity for efficient flame retardant delivery.
3Reliability
If traditional flame-retardant coating processes are used, then flame resistance is achieved, but processing complexity and energy consumption increase
Solution Approach 1:
The patent merges the binder and flame retardant into a single integrated hot melt adhesive composition. This eliminates the need for separate binder application and flame retardant coating steps, significantly simplifying processing compared to traditional multi-step coating processes while maintaining effective flame resistance.
Solution Approach 2:
The patent changes the application temperature parameter from room temperature or low temperature (for aqueous systems) to elevated temperatures typical of hot melt adhesive application (100-200°C). This parameter change enables solvent-free application and eliminates drying steps, reducing processing complexity and energy consumption.
4Reliability
If aqueous coating systems are used, then flame retardancy is achieved, but water consumption and drying energy increase
Solution Approach 1:
The patent extracts and eliminates water from the coating system by using solvent-free polyolefin hot melt adhesives. This removal of the aqueous carrier eliminates the need for drying steps and associated energy consumption, while the flame retardancy function is maintained through the polyolefin-flame retardant composite system.
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 effective flame retardancy, low smoke gas density, and meets stringent fire safety standards with a significant weight reduction and improved recyclability, making it suitable for aircraft carpets and other applications.
Implementation Method 1
When exposed to heat, the expandable graphite expands and forms an intumescent layer on the material surface
Implementation Method 2
Intumescent systems protect the polymer from further pyrolysis by forming a voluminous, insulating protective layer through carbonization and simultaneous foaming
Implementation Method 3
Their effect is their endothermic decomposition releasing water. This leads to a dilution of the combustion gas and a cooling of the polymers. Al(OH)3 decomposes at 230°C with an energy consumption of 75 kJ/mol, while Mg(OH)2 only decomposes at 340°C and an energy consumption of 81 kJ/mol
Implementation Method 4
At the same time, it was found that adding conductive carbon black to the hot melt adhesive according to the invention not only improves the antistatic properties of the textile fabric
Data Source
AI summary
The invention relates to a hot-melt adhesive designed to be flame-resistant, characterised in that said adhesive contains the following components: a) 20 to 70 percent by weight of one or more polyolefin wax(es) of one or more C3-C18 α-olefin(s) and optionally ethylene; b) 9 to 30 percent by weight of expanded graphite; c) 5 to 30 percent by weight of a further flame retardant; d) 0 to 15 percent by weight of an antistatic agent; e) 0 to 12 percent by weight of one or more resin(s); f) 0 to 40 percent by weight of one or more amorphous, atactic poly α-olefin(s) (APAO).