Polyhydroxyalkanoate Melt-Molding with Lamellar Crystal Pretreatment

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Solution Overview

Problem

Crystalline polyhydroxyalkanoates (PHAs) exhibit slow crystallization rates, leading to poor mold processing, agglutination of yarns, and reduced physical properties due to slow crystallization, and existing nucleating agents often compromise strength or cause compatibility issues.

Innovation Solution

A method involving a heating treatment at or above the glass transition temperature to rearrange lamellar crystal thicknesses, allowing partial melting and expansion of the temperature range for melt-molding, using gases, liquids, or solids as heating media.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional heat-molding methods are used for PHA, then the material can be processed, but the cooling time for solidification is long leading to poor productivity

Engineering Contradiction:

Improvecooling time for solidificationVSAvoidcrystallization rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by subjecting the PHA to a heating treatment at a temperature equal to or higher than the glass transition temperature before melt-molding. This preliminary heating rearranges the lamellar crystal thicknesses, creating a more favorable crystalline structure that enables faster solidification during subsequent cooling, thereby reducing cooling time and improving productivity without compromising crystallization reliability

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If PHA is molded through heat-melted state, then processing can be performed, but yarns are wound in an amorphous state leading to agglutination

Engineering Contradiction:

Improvemold processingVSAvoidyarn structure

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The preliminary heating treatment at or above the glass transition temperature rearranges lamellar crystal thicknesses before molding, ensuring that crystals are properly formed and stabilized during the molding process. This prevents yarns from being wound in an amorphous state and eliminates agglutination, while still allowing ease of manufacture through heat-melted state processing

Inventive Principle:

Principle #10Preliminary action

3Reliability

If known crystal nucleating agents are added to improve crystallization rate, then crystallization improves, but strength is reduced and compatibility issues occur

Engineering Contradiction:

Improvecrystallization rateVSAvoidmolded product strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Instead of adding external nucleating agents, the patent changes the physical parameters of the PHA itself by applying heating treatment at or above the glass transition temperature to rearrange lamellar crystal thicknesses. This intrinsic parameter change improves crystallization rate while maintaining the material's original strength and compatibility, avoiding the harmful effects of added nucleating agents

Inventive Principle:

Principle #35Parameter changes

4Productivity

If the temperature range for partial melting is expanded, then mold processing efficiency improves, but thermal decomposition may increase

Engineering Contradiction:

Improvemold processing efficiencyVSAvoidthermal decomposition

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The preliminary heating treatment at or above the glass transition temperature rearranges lamellar crystal thicknesses, which expands the temperature range for partial melting during subsequent processing. This expansion improves mold processing efficiency while the controlled nature of the preliminary treatment prevents excessive thermal decomposition that would occur with uncontrolled high-temperature processing

Inventive Principle:

Principle #10Preliminary action

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

Expands the temperature range for partial melting, improving mold processing efficiency and maintaining strength by promoting crystallization without compromising material properties.

Implementation Method 1

subjecting a crystalline polyhydroxyalkanoate to a heating treatment at a temperature equal to or higher than a glass transition temperature

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

melt-molding a polyhydroxyalkanoate yielded by the heating treatment, which comprises lamellar crystals that are different in lamellar thickness, in a temperature range where some of the lamellar crystals undergo melting and flowing

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS12605875B2Method for producing polymeric molded product comprising pretreatment by heating

Publication Date: 2026.04.21 MITSUBISHI GAS CHEM CO INC

AI summary

An object of the present invention is to provide a method for producing a polymeric molded product, which enables expansion of a temperature range that can be used for partial melting. The method for producing a polymeric molded product, comprises subjecting a crystalline polyhydroxyalkanoate to a heating treatment at a temperature equal to or higher than a glass transition temperature; and melt-molding a polyhydroxyalkanoate yielded by the heating treatment, which comprises lamellar crystals that are different in lamellar thickness, in a temperature range where some of the lamellar crystals undergo melting and flowing, and the other balance lamellar crystals remain unmelted.