Semi-Crystalline Polyester Crystallization Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Polyesters face limitations in high-temperature applications and weatherability, particularly in injection molding and outdoor exposure, due to issues with crystallization, melt points, and cost-effective manufacturing processes.

Innovation Solution

A semi-crystalline polyester with specific repeat units, formed using a method involving transition metal catalysts and polycondensation reactions, exhibiting improved crystallization half-times and melt points, and enhanced weatherability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If PET is used for injection molding, then good moldability is achieved, but high mold temperatures (120-140°C) are required which limits high-temperature application performance

Engineering Contradiction:

ImprovemoldabilityVSAvoidmold temperature requirement

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The patent modifies the chemical composition parameters of polyester by incorporating specific cyclic diol structures (1,4-dioxane-2,5-dimethanol and 1,3-dioxolane-2,5-dimethanol) to change the material's crystallization behavior and thermal properties, enabling good moldability at lower temperatures while maintaining high-temperature performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polyester structure combining terephthalic acid units with cyclic diol units (forming rigid cyclic structures), which synergistically provides both ease of molding and high-temperature stability that neither component alone could achieve

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If polyester is used for outdoor applications, then cost-effectiveness is maintained, but weatherability and surface deterioration occur on ageing

Engineering Contradiction:

Improvecost-effectivenessVSAvoidweatherability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the molecular structure parameters by incorporating cyclic diol units that create rigid, stable polymer chains with enhanced resistance to UV degradation and environmental weathering, while maintaining cost-effectiveness through the use of commercially available monomers

Inventive Principle:

Principle #35Parameter changes

3Reliability

If modified polyester structures are used to improve weatherability, then stability to light is improved, but crystallization half-time increases making them incompatible with current manufacturing equipment

Engineering Contradiction:

Improvestability to lightVSAvoidcrystallization half-time

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent optimizes the balance between cyclic diol content (for weatherability) and linear chain segments (for crystallization rate), achieving a specific compositional range where light stability is enhanced while crystallization half-time remains within acceptable manufacturing parameters (0.5-5.0 minutes at 120°C)

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces localized cyclic structures at specific positions along the polyester chain (through controlled incorporation of cyclic diol units), providing weatherability enhancement at those local sites while maintaining overall chain flexibility and crystallization capability

Inventive Principle:

Principle #3Local quality

4Reliability

If acrylic polymers are compression laminated to polyester surfaces to improve weatherability, then surface properties are retained on extended weathering, but manufacturing cost increases significantly

Engineering Contradiction:

Improvesurface property retentionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and incorporates the weatherability-enhancing functional groups directly into the polyester molecular structure itself, eliminating the need for separate acrylic polymer coating layers while achieving equivalent or superior weather resistance at lower cost

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the weatherability function previously provided by separate acrylic coatings directly into the polyester base material through molecular-level incorporation of cyclic diol units, creating an integrated single-material solution that eliminates additional manufacturing steps and costs

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP3894461B1Polyesters with specified crystallization half-times

Publication Date: 2022.09.28 EASTMAN CHEM CO

AI summary

A semi-crystalline polyester comprising a repeat unit of the formula (I): wherein A is an aliphatic, aromatic, or heterocyclic group; R1 is selected from the group consisting of 1,4-butanediol residue and 1,4-cyclohexanedimethanol residue; R2 is neopentanediol residue; m is between 50 and 99 inclusive; n is between 1 and 50 inclusive; x is between 1 and 200 inclusive; and wherein said semi-crystalline polyester exhibits a minimum crystallization half-time of about 0.3 minutes or greater, or about 0.5 minutes or greater or about 0.6 minutes or greater or about 0.7 minutes or greater is described. The polyesters of the present invention may in various embodiments demonstrate one or more desirable performance characteristics and accordingly are particularly useful in applications and utilities wherein those high levels of performance for such characteristics are required. A process for forming the semi-crystalline polyester is also disclosed.