Flame-Retardant Nylon Fabrics With Melamine-THP Char Formation
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Solution Overview
Problem
Phosphorus-based flame retardants are ineffective on nylon fabrics, causing them to burn faster, and sulfur-based systems result in stiff fabrics with formaldehyde residues and poor hand feel, while high nylon blends melt and stick to skin during fires, posing burn hazards.
Innovation Solution
Combining melamine-based resins with tetrakis(hydroxymethyl)phosphonium-based compounds to enhance flame retardancy, char formation, and durability, minimizing molten nylon polymer formation during combustion, and passing flammability tests after multiple launderings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphorus-based flame retardants are applied to nylon fabrics, then flame retardant treatment is achieved, but the fabric burns at a greater rate than untreated fabric
Solution Approach 1:
The patent combines phosphorus-based flame retardants with melamine-based nitrogen-containing compounds to create a composite flame retardant system. This composite approach allows the phosphorus component to provide flame retardancy while the melamine component neutralizes acidity and promotes char formation, thereby preventing the accelerated burning rate that occurs with phosphorus-only treatments on nylon.
Solution Approach 2:
The melamine-based compound acts as an intermediary substance that modifies the chemical environment during combustion. It neutralizes the acidic conditions created by phosphorus decomposition and provides a protective char layer, thereby mediating between the phosphorus flame retardant mechanism and the nylon polymer to prevent polymer unzipping and excessive fuel supply.
2Reliability
If sulfur-containing materials are used to treat nylon fabrics for flame retardancy, then flame retardant performance is achieved, but the fabric hand becomes very stiff and formaldehyde residues increase
Solution Approach 1:
The patent changes the chemical composition parameters of the flame retardant system by replacing sulfur-containing compounds with a phosphorus-melamine composite system. This parameter change maintains flame retardant effectiveness through synergistic chemistry while eliminating the stiffening effect and formaldehyde residues associated with sulfur-based treatments, thereby preserving fabric hand feel.
3Quantity of substance
If high concentration THP-based aqueous solution is used to increase phosphorous loading on fabric, then flame retardant loading is increased, but the fabric performs poorly on NFPA 12 second bottom vertical test
Solution Approach 1:
The patent creates a composite flame retardant system combining phosphorus-based THP compounds with melamine-based nitrogen-containing compounds. This composite system achieves effective flame retardancy at lower phosphorous loadings because the melamine component contributes to char formation and acid neutralization, thereby passing the NFPA 12 test without requiring high phosphorous concentrations that cause poor performance.
4Ease of operation
If nylon content in fabric blend is increased to achieve desired fabric properties, then fabric performance is improved, but molten nylon polymer forms and sticks to skin during fire
Solution Approach 1:
The patent converts the harmful melting behavior of nylon into a beneficial protective mechanism. The phosphorus-melamine flame retardant system promotes char formation on the nylon surface, and this char layer acts as a thermal barrier that prevents the nylon from melting and sticking to skin, thereby converting the inherent melting hazard into a protective char-based safety mechanism.
Solution Approach 2:
The patent modifies the phase transition behavior of nylon during fire exposure. Instead of allowing the nylon to melt into a sticky liquid, the flame retardant system promotes decomposition into a solid char residue. This phase transition change from melting to charring eliminates the skin adhesion hazard while maintaining the structural integrity needed for fabric performance.
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 melamine-THP combination improves flame retardant performance, maintains fabric softness and strength, and prevents molten nylon polymer formation, ensuring safety and durability in nylon-cellulosic blends, meeting stringent flammability standards.
Implementation Method 1
utilize a reaction of THP chemistry with melamine resin to form a durable FR finish
Implementation Method 2
promote char formation in the combustion zone of fabrics and fabric blends
Implementation Method 3
in the combustion process the phosphorus containing material forms an acidic environment
Implementation Method 4
the nitrogen may catalyze or promote phosphorylation or char formation in the combustion process
Implementation Method 5
nitrogen may catalyze or promote phosphorylation
Implementation Method 6
The mechanism of the sulfur containing materials for reducing the flammability is based on modifying the melt behavior of the nylon polymer
Data Source
AI summary
Embodiments of the present invention use melamine-based resins as a pretreatment on fabrics and fabric blends in combination with phosphorus-based flame retardants to improve flame retardant performance, durability, and further promote char formation in a combustion zone of the fabric.