Branched Diol Modified Polyester for Enhanced Dye Penetration

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Solution Overview

Problem

Polyethylene terephthalate (PET) fibers have high crystallinity and lack functional groups, making it difficult for dye molecules to penetrate the fiber, resulting in poor dyeing properties and high energy consumption due to the need for high-temperature and high-pressure dyeing processes.

Innovation Solution

Introducing a branched diol segment into the molecular chain of a modified polyester, which increases the spatial gap between molecular chains, allowing easier dye penetration and reducing melt viscosity, thereby improving dyeing rates and processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature and high pressure are used for PET dyeing, then dye molecules can penetrate the fiber, but energy consumption increases and dyeing rate remains low

Engineering Contradiction:

Improvedyeing propertyVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent modifies the molecular structure of PET by introducing branched diol segments, which changes the physical parameters of the fiber (spatial gap, free volume) to enable dyeing at lower temperatures and pressures, thereby reducing energy consumption while maintaining dyeing effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure combining linear PET chains with branched diol segments, resulting in a modified polyester that retains the desirable properties of PET while adding improved dye penetration characteristics

Inventive Principle:

Principle #40Composite materials

2Reliability

If high temperature is used to increase free volume for dye penetration, then dyeing is possible, but dyeing rate is not high

Engineering Contradiction:

Improvedyeing propertyVSAvoiddyeing rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent permanently alters the molecular structure by incorporating branched diol segments, which increases the spatial gap and free volume at all temperatures, enabling faster dye penetration rates without requiring extreme temperature increases

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If PET maintains its regular molecular chain structure, then structural regularity and crystallinity are preserved, but spatial gap between molecular chains is small

Engineering Contradiction:

Improvestructural regularityVSAvoidspatial gap

Core Design Contradiction:

Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The patent introduces asymmetric branched structures into the otherwise symmetric and regular PET molecular chain, creating local asymmetry that increases spatial gap while maintaining overall structural integrity and regularity

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent adds a dimensional aspect to the molecular structure by introducing side chains that extend perpendicular to the main chain axis, increasing the three-dimensional spatial gap without disrupting the one-dimensional regularity of the main polymer backbone

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 modified polyester exhibits enhanced dyeing properties and reduced melt viscosity, facilitating better dye diffusion and processing, while maintaining the structural regularity and excellent properties of PET fibers.

Implementation Method 1

the increase of the spatial gap between the molecular chains of the modified polyester is far greater than that of the unbranched polyester at the same temperature, which is beneficial for the fine particles such as the dye entering the modified polyester

Methodology Applied

Scientific EffectSteric hindrance:

Implementation Method 2

The melt viscosity of modified polyester relative to unbranched polyester can also be reduced, which is helpful to reduce processing temperature, reduce degradation rate and facilitate processing

Methodology Applied

Scientific EffectViscosity reduction through molecular structure modification:

Data Source

PatentEP3508511B1Modified polyester and preparation method therefor

Publication Date: 2021.02.24 JIANGSU HENGLI CHEM FIBER

AI summary

The present invention relates to a method for preparing the modified polyester. The modified polyester segments are consisted of terephthalic acid segment, ethylene glycol diol segment and branched diol segment, in which the branched diol segment refers to a diol segment in which a branch is located on a non-terminal carbon in the glycol segment and the branch is a linear carbon chain having 5 to 10 carbon atoms. The method for preparing the modified polyester is to get terephthalic acid glycol ester through the esterification of terephthalic acid and branched diol using the concentrated sulfuric acid as the catalyst. Then get ethylene terephthalate through the esterification of terephthalic acid and ethylene glycol. After stirring and mixing the two, the modified polyester can be obtained through polycondensation reaction of a low vacuum stage and a high vacuum stage using the catalyst and stabilizer. The increase rate of the space between the internal molecular chain of the modified polyester is far greater than that of the polyester without branches at the same temperature, thus it can help tiny particles such as dyes into the modified polyester, and improve the dyeing rate.