Aromatic Polyester Fiber Melt Flow Modification
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Solution Overview
Problem
Aromatic polyesters, such as PET, PTT, and PBT, are challenging to form into nonwoven webs due to high melting points and low bond flexibility, while other polyesters like PBS and PCL have a small bonding window, making it difficult to produce nonwoven webs at high speeds with good mechanical and physical properties.
Innovation Solution
A method involving the modification of aromatic polyesters with a polyether copolymer in a melt processing device to create a thermoplastic composition with improved melt flow rate, comprising 75-99 wt% aromatic polyester and 1-25 wt% polyether copolymer, where the polyether copolymer contains specific repeating units to enhance processing and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aromatic polyester is used to form nonwoven webs, then good mechanical and physical properties are achieved, but high melting points and low bond flexibility make processing difficult
Solution Approach 1:
The patent uses a composite material system consisting of aromatic polyester blended with polyether copolymer (specifically PEG-PPG-PEG block copolymer). This composite approach combines the strength and rigidity of aromatic polyester with the flexibility and low melting point of polyether copolymer, enabling both good mechanical properties and ease of processing into nonwoven webs.
Solution Approach 2:
The patent changes the chemical composition parameters of the polyester by incorporating polyether copolymer at specific concentrations (0.1-10% by weight). This parameter modification lowers the melting point and increases bond flexibility while maintaining the mechanical integrity provided by the aromatic polyester base material.
2Ease of operation
If polyesters like PBS and PCL are used, then low glass transition temperature and softness are achieved, but small bonding window makes high-speed production difficult
Solution Approach 1:
The patent optimizes the bonding window parameters by controlling the polyether copolymer content and molecular weight. The specific composition (PEG-PPG-PEG block copolymer with defined repeating units) provides an extended bonding window that accommodates high-speed processing while maintaining softness and flexibility.
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 resulting thermoplastic composition exhibits improved processability, increased melt flow rate, and reduced glass transition temperature, allowing for the formation of fibers and nonwoven webs with enhanced mechanical properties and processing flexibility.
Implementation Method 1
supplying at least one aromatic polyester to a melt processing device and modifying the aromatic polyester with at least one polyether copolymer within the device to form a thermoplastic composition
Data Source
AI summary
A method for forming a fiber is provided. The method comprises supplying at least one aromatic polyester to a melt processing device and modifying the aromatic polyester with at least one polyether copolymer within the device to form a thermoplastic composition having a melt flow rate that is greater than the melt flow rate of the aromatic polyester. The polyether copolymer contains a repeating unit (A) having the following formula:wherein,x is an integer from 1 to 250,a the polyether copolymer further containing a repeating unit (B) having the following formula:wherein,n is an integer from 3 to 20; andy is an integer from 1 to 150.