Coated Metal Hydroxides in Thermoplastic Polyurethane
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Solution Overview
Problem
Flame-retardant thermoplastic polyurethanes face challenges in achieving good mechanical properties, industrial flame retardancy, hydrolysis resistance, and aging resistance, particularly oxidative aging resistance, when using metal hydroxides as halogen-free flame retardants.
Innovation Solution
A flame-retardant thermoplastic polyurethane is developed using metal hydroxides coated with phosphorus-containing derivatives of phosphoric acid, phosphonic acid, or phosphinic acid, and hydrotalcite or phyllosilicate, which improves mechanical strength and flame retardancy while maintaining non-toxic smoke production during combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal hydroxides are used as halogen-free flame retardants in TPU, then flame retardancy and low smoke toxicity are improved, but aging resistance and mechanical properties deteriorate
Solution Approach 1:
The patent introduces silane coupling agents as intermediary substances that coat the metal hydroxide particles, creating a protective interface between the flame retardant and the TPU matrix. This intermediary layer prevents direct interaction between the metal hydroxides and the polymer, thereby maintaining flame retardancy while protecting against hydrolysis and oxidative aging.
Solution Approach 2:
The invention creates a composite structure by combining metal hydroxides with silane coupling agents to form coated particles. This composite approach allows the system to simultaneously achieve flame retardancy from the metal hydroxides and improved aging resistance from the silane coating, resolving the contradiction between these two properties.
2Object-generated harmful factors
If metal hydroxides are used as flame retardants, then toxic smoke evolution is reduced, but hydrolysis resistance deteriorates
Solution Approach 1:
The silane coupling agent serves as a protective intermediary between the metal hydroxides and the TPU matrix, preventing water from reaching and hydrolyzing the polymer chains. This intermediary layer maintains the low smoke toxicity benefit while protecting against hydrolysis degradation.
Solution Approach 2:
The silane coupling agent forms a thin protective film around the metal hydroxide particles, creating a barrier that prevents water penetration and hydrolysis of the TPU matrix, thereby improving hydrolysis resistance while maintaining flame retardancy.
3Reliability
If metal hydroxides are used as flame retardants, then flame safety is improved, but mechanical properties deteriorate
Solution Approach 1:
The silane coupling agent acts as a mediator that improves the interfacial adhesion between metal hydroxides and TPU, creating a stronger composite material. This intermediary layer allows the system to achieve both flame safety from the metal hydroxides and improved mechanical properties from the enhanced interfacial bonding.
Solution Approach 2:
The invention creates a composite material system where metal hydroxides provide flame safety and silane coupling agents provide structural reinforcement through improved interfacial adhesion, allowing both flame safety and mechanical properties to be simultaneously optimized.
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 coated metal hydroxides enhance mechanical properties and flame retardancy, significantly improving oxidative aging resistance and maintaining effective flame retardancy without adverse effects on the thermoplastic polyurethane.
Implementation Method 1
at least one flame retardant is a metal hydroxide at least to some extent coated by a coating, having at least one phosphorus-containing flame retardant which is a derivative of phosphoric acid, phosphonic acid, and/or phosphinic acid
Implementation Method 2
Metal hydroxides can also be used, alone or in combination with phosphorus-containing flame retardants and/or with phyllosilicates, as halogen-free flame retardants in TPU
Implementation Method 3
at least one flame retardant is a metal hydroxide at least to some extent coated by a coating, having at least one phosphorus-containing flame retardant
Data Source
AI summary
The invention relates to a flame-retardant thermoplastic polyurethane based on at least one diisocyanate and on at least one substance reactive toward isocyanate, and preferably on at least one chain extender, and also optionally on at least one catalyst, and comprising at least one flame retardant, and also optionally additives and/or auxiliaries, where one flame retardant is a metal hydroxide at least to some extent surrounded by a coating, the material comprises, as further flame retardant, at least one phosphorus-containing flame retardant which is a derivative of phosphoric acid, phosphonic acid, and/or phosphinic acid and the material further comprises hydrotalcite and/or phyllosilicate, and also to an associated production process and the use.