EVOH Copolymer Thermal Stretching via Master Batch Mediator
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Solution Overview
Problem
Current ethylene-vinyl alcohol copolymers (EVOH) face challenges in achieving improved stretching properties, gas barrier properties, appearance, and strength, particularly in deep containers and multi-layer containers, due to issues with compatibility, adhesion, and thermal stability, which affect their performance in packaging applications such as food, pharmaceuticals, and fuel containers.
Innovation Solution
The development of a new ethylene-vinyl alcohol copolymer with a structural unit containing a 1,2-glycol bond, obtained through copolymerization of 3,4-diacyloxy-1-butene, a vinyl ester monomer, and ethylene, which is then hydrolyzed, and optionally containing a boron compound, to enhance thermal stability and gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plasticizer is added to EVOH to improve stretching properties, then thermal stretching properties are improved, but gas barrier properties decrease
Solution Approach 1:
The patent uses a specific master batch containing a blending resin as an intermediary substance to improve thermal stretching properties without directly adding plasticizer to the EVOH. This master batch acts as a mediator that transfers the stretching improvement benefit while preserving the gas barrier properties of the EVOH layer.
Solution Approach 2:
The patent segments the stretching improvement function into a separate multi-layer structure where the EVOH layer maintains its gas barrier properties while an adjacent layer provides the thermal stretching properties. This segmentation allows each layer to perform its specialized function without compromising the other.
2Ease of operation
If polyamide resin is mixed with EVOH to improve stretching properties, then thermal stretching properties are improved, but long run melt moldability decreases
Solution Approach 1:
The patent introduces a master batch as an intermediary carrier that contains the blending resin in a controlled concentration (1-10 parts by weight per 100 parts by weight of EVOH). This intermediary form allows the stretching improvement to be achieved while maintaining long run melt moldability that would be lost with direct mixing.
Solution Approach 2:
The patent carefully controls the concentration parameter of the blending resin within a specific range (1-10 parts per 100 parts of EVOH) to optimize both stretching properties and melt moldability. This parameter control prevents the degradation of long run melt moldability while achieving the desired stretching improvement.
3Ease of operation
If different composition EVOH are mixed to improve stretching properties, then thermal stretching moldability is improved, but compatibility and adhesion are not completely homogeneous
Solution Approach 1:
The patent uses a master batch that provides a homogeneous distribution of the blending resin throughout the EVOH composition. This master batch approach ensures uniform compatibility and adhesion properties throughout the molded article, avoiding the inhomogeneity that would result from directly mixing different EVOH compositions.
4Adaptability or versatility
If deep containers with high drawing ratio are molded to improve variety and design properties, then container shape and design are improved, but appearance, barrier properties and strength deteriorate
Solution Approach 1:
The patent uses the master batch as an intermediary that enables the molding of deep containers with high drawing ratios while maintaining appearance, barrier properties, and strength. The controlled release of stretching improvement from the master batch allows the EVOH to withstand the stresses of high drawing ratio molding without deteriorating its critical properties.
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 new EVOH exhibits improved stretching properties, gas barrier performance, and strength, ensuring excellent appearance and durability in molded articles, including deep containers and multi-layer structures, while maintaining compatibility and adhesion, thus meeting the demands of various packaging applications.
Implementation Method 1
copolymerization of 3,4-diacyloxy-1-butene, a vinyl ester monomer, and ethylene, which is then hydrolyzed
Data Source
AI summary
An ethylene-vinyl alcohol copolymer and a molded article thereof are disclosed. The ethylene-vinyl alcohol copolymer has improved stretching properties and provides the molded article with excellent gas barrier properties, appearance and strength. The ethylene-vinyl alcohol copolymer comprises the structural unit of formula (1):(wherein X represents any binding chain excluding an ether bond, each of R1 to R4 represents independently any substituent and n represents 0 or 1.).