EVOH Polyamide Resin Composition Retort Resistance
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Solution Overview
Problem
Conventional resin compositions containing ethylene-vinyl alcohol copolymers (EVOH) and polyamides (PA) face challenges in retort resistance and are prone to burnt deposits during long-term operations, leading to contamination, increased production costs, and odor issues.
Innovation Solution
A resin composition comprising EVOH with an ethylene content of 20-60 mol%, polyamide, a carboxylic acid metal salt, and a saturated carbonyl compound, specifically a saturated aldehyde or ketone, with defined ratios and concentrations to enhance retort resistance and inhibit burnt deposit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVOH and PA are blended to improve retort resistance, then hot water resistance is improved, but crosslinking reaction occurs leading to burnt deposits generation
Solution Approach 1:
A boron compound is introduced as an intermediary substance to inhibit the crosslinking reaction between EVOH and PA. The boron compound acts as a mediator that prevents direct harmful interactions between the polymer components, thereby suppressing burnt deposit formation while preserving the retort resistance benefits of the EVOH/PA blend.
Solution Approach 2:
The invention changes the chemical environment parameters by adding the boron compound, which alters the reaction kinetics and prevents crosslinking. This parameter change (introduction of boron-containing species) transforms the system from one prone to crosslinking to one where the polymers remain stable during extrusion and processing.
2Productivity
If conventional resin composition is used for long-term operation, then production continues, but burnt deposits accumulate leading to contamination and increased cleaning frequency
Solution Approach 1:
The boron compound is added in advance to the resin composition to prevent crosslinking reactions before they can occur during long-term extrusion. This preliminary protective action ensures that burnt deposits do not form during continuous operation, maintaining formed article quality throughout extended production periods without requiring frequent shutdowns for cleaning.
3Reliability
If shutdown and cleaning is performed frequently to remove burnt deposits, then formed article quality is maintained, but production cost increases and production time is lost
Solution Approach 1:
The boron compound enables continuous extrusion operation by preventing burnt deposit formation throughout the entire production period. This allows the extrusion process to run continuously without interruption for cleaning, maximizing productivity and eliminating production time losses while maintaining formed article quality through the preventive action of the boron compound.
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 composition significantly improves retort resistance and reduces the generation of burnt deposits and odor, enabling longer continuous operation without contamination, thus reducing production costs and maintaining product quality.
Implementation Method 1
a crosslinking reaction may proceed between a hydroxyl group or a terminal carboxyl group of the EVOH and an amide group, a terminal amino group or a terminal carboxyl group of the PA, leading to nonuniformity of a resin viscosity, and resulting in significant generation of burnt deposits within an extruder, a screw and a die during melt molding over a long time period
Data Source
AI summary
Provided is a resin composition that is superior in retort resistance as well as inhibitory effects on the odor and generation of burnt deposits in an operation over a long time period. The resin composition contains: an ethylene-vinyl alcohol copolymer (A) having an ethylene content of 20 mol% or greater and 60 mol% or less; a polyamide (B); a carboxylic acid metal salt (C); and a saturated carbonyl compound (D) having 3 to 8 carbon atoms, wherein the saturated carbonyl compound (D) is a saturated aldehyde (D-1), a saturated ketone (D-2) or a combination thereof, the mass ratio (A/B) of the ethylene-vinyl alcohol copolymer (A) to the polyamide (B) is 60/40 or greater and 95/5 or less, the content of the carboxylic acid metal salt (C) with respect to the resin content in terms of metal element equivalent is 1 ppm or greater and 500 ppm or less, and the content of the saturated carbonyl compound (D) with respect to the resin content is 0.01 ppm or greater and 100 ppm or less.