Polyester-Poly(ester-ether) Blend for Heat Stability
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Solution Overview
Problem
Poly(ester-ether)copolymers have limited heat stability and lack sufficient high notched Izod impact strength at low temperatures, making them unsuitable for applications requiring improved thermal resistance and low-temperature durability, such as automotive parts.
Innovation Solution
A thermoplastic composition is developed by blending 10-45% polyester with 55-90% poly(ester-ether)copolymer, incorporating units derived from terephthalic acid, butane diol, and poly(oxytetramethylene)glycol, along with antioxidant stabilizers and beta-(3,4-epoxycyclohexyl)ethyl triethoxysilane, which maintains at least 50% of tensile strength and elongation at break after exposure to high temperatures and exhibits improved low-temperature notched Izod impact ductility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If poly(ester-ether)copolymers are used alone, then elastomeric properties and processability are achieved, but heat stability is insufficient
Solution Approach 1:
The patent creates a composite material system by blending poly(ester-ether)copolymer with polyester and carboxy-reactive compounds. This composite approach combines the elastomeric properties of poly(ester-ether)copolymer with the heat stability of polyester, resolving the contradiction between achieving elastomeric behavior and maintaining heat stability. The specific formulation ranges (5-50 wt% polyester, 0.1-5 wt% carboxy-reactive compound) optimize this composite structure for simultaneous heat resistance and elastomeric performance.
Solution Approach 2:
The patent modifies the chemical composition parameters of the poly(ester-ether)copolymer system by introducing carboxy-reactive compounds in controlled amounts (0.1-5 wt%). This parameter change enables the material to develop improved heat stability through chemical interaction, while maintaining the base elastomeric properties. The controlled adjustment of compositional parameters resolves the heat stability deficiency without sacrificing the fundamental elastomeric characteristics.
2Temperature
If heat stability is improved through blending, then thermal resistance increases, but low temperature impact strength may deteriorate
Solution Approach 1:
The patent carefully controls the compositional parameters to maintain low-temperature impact strength. The polyester content is limited to 5-50 wt% and carboxy-reactive compounds to 0.1-5 wt%, preventing excessive crosslinking or rigidity that would harm impact strength. This precise parameter control allows thermal resistance improvement while preserving the ductility and impact resistance needed for low-temperature performance.
Solution Approach 2:
The patent applies local quality modification by introducing carboxy-reactive compounds that selectively interact with polyester components. This localized chemical interaction enhances heat stability in specific regions of the blend without uniformly affecting the entire material structure, thereby preserving the low-temperature impact properties in the poly(ester-ether)copolymer matrix while improving thermal resistance where needed.
3Temperature
If polyester content is increased to improve heat stability, then processing complexity increases
Solution Approach 1:
The patent optimizes the polyester content parameter to a moderate range (5-50 wt%) rather than using high concentrations, which would require complex processing equipment and conditions. This moderate parameter level achieves sufficient heat stability improvement while maintaining compatibility with standard thermoplastic processing methods, avoiding the need for specialized high-complexity processing infrastructure.
Solution Approach 2:
The carboxy-reactive compound acts as an intermediary that facilitates the interaction between polyester and poly(ester-ether)copolymer. This intermediary enables effective heat stability improvement at lower polyester concentrations, reducing the need for high polyester content that would complicate processing. The intermediary promotes uniform distribution and reaction, simplifying the overall processing requirements.
Data Source
AI summary
A composition, comprising a blend of 10 to 45 weight percent of a polyester selected from the group consisting of poly(ethylene terephthalate), poly(butylene terephthalate), poly(1,4-cyclohexyldimethylene cyclohexyl dicarboxylate), or a combination comprising at least one of the foregoing; and 55 to 90 weight percent of a poly(ester-ether)copolymer, each based on the total weight of the polyester and the poly(ester-ether)copolymer; wherein the poly(ester-ether)copolymer comprises units derived from terephthalic or a chemical equivalent thereof, units derived from butane diol or a chemical equivalent thereof, and 25 to 65 weight percent of units derived from poly(oxytetramethylene)glycol or a chemical equivalent thereof, based on the weight of the copolymer; wherein the composition retains at least 50% of at least one of tensile strength, modulus, stress at maximum strain, or the elongation at break is larger than 150% after being exposed to a temperature of 140° C. for 70 hours, as measured by ASTM D-638.