Resin Composition with Carbonyl Compound for Thermoforming
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Solution Overview
Problem
Conventional resin compositions and production methods face challenges in maintaining appearance quality and impact resistance when recycling and reusing thermoformed containers, leading to issues like gelation, adhesion, and surface roughness, especially during prolonged melt molding processes.
Innovation Solution
A resin composition comprising an ethylene-vinyl alcohol copolymer, polyolefin, and a carbonyl compound, specifically an unsaturated aldehyde, saturated aldehyde, or saturated ketone, is used, with the carbonyl compound content between 0.01 ppm and 100 ppm, to inhibit burnt deposits and enhance impact resistance, while an acid-modified polyolefin and fatty acid metal salt are added to improve compatibility and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional resin compositions are used for recycling and reusing thermoformed containers, then production efficiency is maintained, but gelation and adhesion occur during prolonged melt molding, reducing continuous operation time
Solution Approach 1:
The patent introduces a specific carbonyl compound (aldehyde or ketone with 3-8 carbon atoms) as an intermediary substance that mediates between the polyolefin and EVOH components. This carbonyl compound prevents direct harmful interactions between the resin components during prolonged heating, thereby preventing gelation and adhesion while maintaining continuous production capability
Solution Approach 2:
The patent changes the chemical composition parameters by adding a specific carbonyl compound (0.01-100 ppm) to the resin system. This parameter change modifies the thermal behavior and chemical stability of the recycled material, preventing degradation during prolonged melt molding operations and extending continuous operation time
2Ease of manufacture
If conventional resin compositions are used for recycling, then production cost is reduced through material reuse, but surface roughness and appearance quality deteriorate
Solution Approach 1:
The carbonyl compound acts as a protective intermediary that prevents direct contact and adhesion between deteriorated matter and the extruder surface. This intermediary layer maintains surface smoothness and appearance quality even when recycling conventional materials, allowing cost-effective material reuse without quality loss
3Reliability
If polyolefin and EVOH are combined in multilayer structure, then oxygen barrier properties are improved, but compatibility between layers is poor leading to separation and reduced mechanical strength
Solution Approach 1:
The patent creates a composite material system where a carbonyl compound is integrated into the polyolefin matrix. This composite structure improves interfacial compatibility between the polyolefin and EVOH layers, enabling strong adhesion while maintaining the oxygen barrier properties of the EVOH layer
Solution Approach 2:
The patent modifies the chemical composition of the polyolefin layer by incorporating a specific carbonyl compound (0.01-100 ppm). This compositional change creates favorable interfacial conditions for bonding with EVOH, improving layer adhesion and overall mechanical strength while preserving the barrier functionality
4Strength
If fatty acid metal salt is added to improve compatibility, then layer adhesion is enhanced, but burnt deposits form during prolonged operation
Solution Approach 1:
The carbonyl compound serves as a superior intermediary that replaces the need for fatty acid metal salts. It provides the necessary compatibility and adhesion enhancement between layers without forming burnt deposits during prolonged heating, eliminating the harmful side effects associated with traditional additives
Solution Approach 2:
The patent extracts and eliminates the need for fatty acid metal salts from the resin composition. By removing these problematic additives and using only the carbonyl compound, the system achieves both good layer adhesion and freedom from burnt deposits during continuous operation
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 solution effectively extends the continuous operation time of thermoforming equipment, prevents surface defects, and maintains the mechanical strength and appearance quality of the multilayered containers even after multiple recycling cycles, making it suitable for various packaging applications.
Implementation Method 1
gelation that occurs due to heat deterioration of the material during melt molding
Implementation Method 2
adhesion of a deteriorated matter to the inside wall of an extruder
Implementation Method 3
heat deterioration of the material during melt molding
Implementation Method 4
superior oxygen barrier properties due to including the EVOH layer
Data Source
AI summary
Provided is a resin composition exhibiting inhibited generation of defects in thermoforming, and having a superior appearance and sufficient strength. Also provided are a multilayer structure and a thermoformed container that exhibit superior appearance characteristics and impact resistance even when a recovered material obtained by repeatedly recovering a remnant, a scrap and the like of a sheet containing the resin composition is used. The resin composition contains: an ethylene-vinyl alcohol copolymer (A); a polyolefin (B); and a carbonyl compound (C) having 3 to 8 carbon atoms. The carbonyl compound (C) is an unsaturated aldehyde (C-1), a saturated aldehyde (C-2), a saturated ketone (C-3) or a combination thereof, and the content of the carbonyl compound (C) is 0.01 ppm or greater and 100 ppm or less.