Graft-Modified Ammonium Polyphosphate for Hydrolysis Resistance
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Solution Overview
Problem
Ammonium polyphosphate, a halogen-free flame retardant, faces issues with hydroplaning, poor water resistance, and incomplete coating treatments, which limit its application in high-temperature and humid environments, and can release harmful substances like formaldehyde during processing.
Innovation Solution
A method involving the hydrolysis of amino silane using ammonia water, followed by reaction with phosphorus pentoxide and melamine, to produce graft-modified ammonium polyphosphate with ultra-low hydroplaning and resistance to hydrolysis, ensuring thorough grafting and improved water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional coating treatment (microencapsulation with melamine formaldehyde resin, epoxy resin, or urea resin) is applied to ammonium polyphosphate, then water solubility and viscosity are reduced, but initial decomposition temperature decreases and formaldehyde may be released during high-temperature processing
Solution Approach 1:
The patent uses silane coupling agent as an intermediary substance that bridges the inorganic ammonium polyphosphate and organic resin matrix. The silane groups react with both the phosphate groups of APP and the hydroxyl groups of the resin, forming a stable interfacial layer that improves compatibility without compromising thermal stability or releasing harmful substances.
Solution Approach 2:
The patent modifies the surface chemistry parameters of ammonium polyphosphate by introducing silane groups, changing the surface energy, hydrophobicity, and chemical reactivity. This parameter change enables better interfacial bonding with the resin matrix while maintaining the core thermal properties of APP.
2Ease of operation
If silicone oil coating is applied to ammonium polyphosphate, then viscosity and dispersibility are improved, but coating completeness decreases and water resistance deteriorates under thermal processing
Solution Approach 1:
Silane coupling agent serves as a chemical intermediary that forms strong covalent bonds with both the ammonium polyphosphate surface and the resin matrix, creating a stable interface that maintains water resistance even under thermal processing conditions, unlike physical silicone oil coatings.
3Adaptability or versatility
If grafting treatment with organic amine is applied to ammonium polyphosphate, then compatibility with resin is improved, but grafting completeness is poor due to weak reaction activity
Solution Approach 1:
The silane coupling agent acts as a reactive intermediary that first hydrolyzes to form silanol groups, then condenses with hydroxyl groups on the ammonium polyphosphate surface, creating stable Si-O-P bonds. This two-step mechanism ensures complete and stable grafting, overcoming the weak reaction activity of direct organic amine grafting.
4Reliability
If silane structure is introduced during synthesis of ammonium polyphosphate, then processing time increases and incomplete polymerization occurs, but water resistance is improved
Solution Approach 1:
The silane modification is performed as a preliminary surface treatment step before the main ammonium polyphosphate synthesis. The silane coupling agent is pre-hydrolyzed and then grafted onto the APP surface during or after synthesis, allowing the bulk polymerization to proceed independently and completely without time loss.
5Reliability
If ammonium polyphosphate is used in electrical components exposed to water vapor, then flame retardancy is provided, but precipitation occurs due to poor hydrolysis resistance
Solution Approach 1:
The silane coupling agent creates a protective interfacial layer that acts as a barrier against water vapor penetration. This intermediary layer prevents water from reaching the ammonium polyphosphate core, thereby preventing hydrolysis and precipitation while maintaining the flame retardant's effectiveness in electrical components.
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 method significantly reduces hydroplaning and water solubility, enhances high-temperature and humidity resistance, and expands the application scope of ammonium polyphosphate, while maintaining flame retardant efficiency and avoiding harmful by-products.
Implementation Method 1
hydrolyzing amino silane under the condition of ammonia water
Implementation Method 2
graft modified ammonium polyphosphate
Data Source
AI summary
A method for preparation of graft modified ammonium polyphosphate with ultra-low hydroplaning and resistance to hydrolysis belongs to the field of the preparation of flame retardant. Ammonia water is used as hydrolytic agent of amino silane. In the early stage of synthesis of ammonium polyphosphate with phosphorus pentoxide, diammonium hydrogen phosphate and melamine as raw materials, hydrolyzed amino silane ammonia mixture is added, and continues warming reaction, when the temperature drops to a certain temperature, melamine is added to maintain high temperature reaction for a certain period of time, then cools to obtain graft modified ammonium polyphosphate with ultra-low hydroplaning and resistance to hydrolysis. The present disclosure grafts ammonium polyphosphate with two kinds of amino grafting in stages, and the modified ammonium polyphosphate products after grafted basically have no hydroplaning when meets water. Because of addition of excessive melamine in late stage, the excessive melamine is not only used for graft modified ammonium polyphosphate, but also used for reacting with acidic ammonium polyphosphate whose polymerization is incomplete, making it form polyphosphate melamine, eliminate the formation of water-soluble small molecules, and reduce water solubility of the products to a greater extent.