Polylactic Acid Resin Composition Moldability
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Solution Overview
Problem
Polylactic acid resin has a low crystallization rate, leading to insufficient heat resistance, elastic modulus, and moldability, which results in deformation during short molding periods and defects in molded articles.
Innovation Solution
A polylactic acid resin composition is developed by adding carboxylic acid amides and esters with polar groups and a (meth)acrylate compound, along with fibers, to enhance crystallization and moldability, with specific additives like ethylenebis-12-hydroxystearic acid amide and kenaf fibers, and optimizing mold temperature settings during injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polylactic acid is molded in a short period of time, then productivity is improved, but the crystallization rate is insufficient leading to poor heat resistance and elastic modulus
Solution Approach 1:
The patent applies preliminary action by incorporating nucleating agents and crystallization promoters into the polylactic acid resin composition before molding. These additives are pre-mixed with the resin to ensure that crystallization nuclei are already present and ready to facilitate rapid crystallization during the molding process, enabling sufficient crystallization to occur within short molding cycles without requiring extended processing times
Solution Approach 2:
The patent employs parameter changes by carefully controlling molding temperature, pressure, and time parameters to optimize crystallization. By adjusting these parameters - particularly maintaining the molding temperature near or above the crystallization temperature of polylactic acid - the process enables rapid and sufficient crystallization to occur during brief molding cycles, resolving the contradiction between speed and crystallization quality
2Productivity
If a transparent nucleating agent such as aliphatic amide is added to polylactic acid, then the crystallization rate is increased, but the effect is not sufficient and heat treatment after molding is required
Solution Approach 1:
The patent merges multiple functional additives into a single resin composition system. It combines nucleating agents, crystallization promoters, and processing aids into one integrated formulation that simultaneously achieves rapid crystallization and good moldability. This combination eliminates the need for separate heat treatment steps after molding, as the synergistic action of the additive package ensures sufficient crystallization occurs during the molding process itself
Solution Approach 2:
The patent creates a composite resin composition by combining polylactic acid with multiple functional additives including nucleating agents and crystallization promoters. This composite material formulation is designed to work together synergistically to achieve both high crystallization rate and excellent moldability, eliminating the need for post-molding heat treatment and simplifying the overall manufacturing process
3Reliability
If the crystallinity of polylactic acid is increased, then heat resistance and elastic modulus are improved, but the crystal solidification in mold is insufficient causing deformation during mold releasing
Solution Approach 1:
The patent applies local quality by using additives that promote crystallization specifically in the mold region where it is needed. The nucleating agents and crystallization promoters are distributed throughout the resin but become particularly active in the mold cavity, facilitating localized crystallization that enhances heat resistance while the controlled nature of this localized crystallization prevents excessive crystal growth that would cause deformation during mold release
Solution Approach 2:
The patent employs dynamics by creating a dynamic crystallization process that adapts to molding conditions. The crystallization rate and crystal structure development are dynamically controlled through the additive package and processing parameters, allowing the material to crystallize sufficiently during molding to prevent deformation while maintaining the flexibility needed for smooth mold release. The process dynamically balances crystallization promotion with moldability
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 significantly improves moldability and heat resistance, preventing deformation during short molding times and enhancing the mechanical properties of the molded articles, while maintaining operability and reducing defects.
Implementation Method 1
a polylactic acid resin reacted with a (meth)acrylate compound
Implementation Method 2
it is important that the resin be crystallized in order to exhibit the original material properties thereof, such as heat resistance
Implementation Method 3
adding a transparent nucleating agent such as aliphatic amide to aliphatic polyesters, such as polylactic acid
Implementation Method 4
at least one kind of low molecular compound selected from a carboxylic acid amide and a carboxylic acid ester each of which has a polar group in a molecule
Data Source
AI summary
Provided is a polylactic acid resin composition obtained by adding a carboxylic acid amide and a carboxylic acid ester each of which has at least one polar group in a molecule to a polylactic acid resin reacted with a (meth)acrylate compound. Also provided is a polylactic acid resin molded article which is a molded article obtained by molding the polylactic acid resin composition, manufactured by setting a mold temperature to a glass transition temperature of a polylactic acid resin plus 20° C. or higher and a melting point thereof minus 20° C. or lower, at the time of injection molding the polylactic acid resin composition. Thus, a resin composition in which a moldability is improved at a temperature at which a polylactic acid resin is crystallized, and a molded article therefrom are provided.