Polylactic Acid Resin Composition Fire Retardancy
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Solution Overview
Problem
Polylactic acid resins face issues with bleed-resistance and molecular weight retention due to the hydrolysis promoted by high alkali metal-containing substances in metal hydrates when combined with common phosphorous compounds, leading to decomposition and reduced fire retardancy.
Innovation Solution
A polylactic acid resin composition incorporating a metal hydrate with an alkali metal-containing substance content of not more than 0.2% by mass and a phosphazene derivative, which inhibits hydrolysis and enhances bleed-resistance and molecular weight retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal hydrates with high alkali metal-containing substance content are used to achieve good fire retardancy, then fire retardancy is improved, but hydrolysis of phosphorous compounds is promoted leading to poor bleed-resistance and reduced molecular weight retention
Solution Approach 1:
The invention changes the chemical composition parameters of the metal hydrate by strictly limiting the alkali metal-containing substance content to 0.03% by mass or less, and the alkaline earth metal-containing substance content to 3% by mass or less. This parameter optimization prevents hydrolysis promotion while maintaining fire retardancy effectiveness.
Solution Approach 2:
The invention creates a composite fire retardant system combining metal hydrate (with controlled composition), phosphorous compound, and polyhydroxycarboxylic acid or its derivative. This composite approach synergistically achieves fire retardancy while preventing hydrolysis through the combined action of all components.
2Reliability
If common phosphorous compounds are combined with metal hydrates containing alkali metal-containing substance, then fire retardancy is achieved, but decomposition of polylactic acid is accelerated resulting in lowered molecular weight
Solution Approach 1:
The invention optimizes the chemical composition parameters of metal hydrate by limiting alkali metal-containing substance to 0.03% by mass or less, thereby preventing accelerated decomposition of polylactic acid and preserving molecular weight while maintaining fire retardancy.
Solution Approach 2:
The invention introduces polyhydroxycarboxylic acid or its derivative as an intermediary substance that mediates between the metal hydrate and phosphorous compound, preventing direct harmful interactions that would cause polylactic acid decomposition while maintaining fire retardancy effectiveness.
3Reliability
If metal hydrates with high alkali metal-containing substance are used, then fire retardancy is improved, but phosphorous compounds or decomposed products are easily bled from the original material
Solution Approach 1:
The invention changes the compositional parameters of metal hydrate by strictly limiting alkali metal-containing substance to 0.03% by mass or less, preventing the promotion of phosphorous compound hydrolysis and subsequent bleeding from the polylactic acid matrix.
Solution Approach 2:
The invention uses polyhydroxycarboxylic acid or its derivative as an intermediary that stabilizes the interaction between metal hydrate and phosphorous compound, preventing decomposition products from bleeding out of the original material while maintaining fire retardancy.
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 composition achieves excellent bleed-resistance and molecular weight retention while maintaining good fire retardancy, as demonstrated by the examples provided.
Implementation Method 1
a phosphazene derivative (c); and a polylactic acid resin molded body formed by molding said polylactic acid resin composition... the hydrolysis of phosphorous compounds is promoted by the alkali metal-containing substance... hydrolysis of phosphorous compounds could not be inhibited
Data Source
AI summary
Disclosed is a polylactic acid resin composition having excellent bleed resistance and molecular weight retention ratio. A polylactic acid resin molded body is also disclosed. The polylactic acid resin composition contains a polylactic acid resin (a), a metal hydrate (b) having an alkali metal-containing substance content of not more than 0.2% by mass, and a phosphazene derivative (c). The polylactic acid resin molded body is obtained by molding the polylactic acid resin composition. Specifically, a polylactic acid molded body can be produced by filling a melt of the polylactic acid resin composition into a mold at a temperature in the range from glass transition temperature of said polylactic acid resin (a) to 110° C. and molding the melt therein.