Recycling Agent Compatibilizer for EVOH Multilayer Resin
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Solution Overview
Problem
During melt processing of multilayer structures containing an ethylene-vinyl alcohol copolymer (EVOH) and thermoplastic resin layers, issues such as adhesion of degraded resin to molding machine screws, die build-up, and decreased transparency occur due to reactions with adhesive resins, leading to suboptimal recycling agent performance in existing techniques.
Innovation Solution
A mixed resin comprising a recycling agent formed by reacting a modified olefin-based polymer with a polymer containing terminal functional groups, which acts as a compatibilizer to improve compatibility between EVOH and thermoplastic resin layers, preventing adhesion and die build-up while maintaining transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional recycling agents (acid grafted polyolefin-based resin, fatty acid metal salt, or specific metal compound) are used, then some adhesion problems are reduced, but die build-up and fish eye generation are not sufficiently inhibited
Solution Approach 1:
The patent introduces a novel recycling agent comprising a polyolefin-based resin with grafted polar groups (carboxyl, hydroxyl, or amino groups) as an intermediary substance that mediates between the EVOH layer and thermoplastic resin layer. This intermediary agent specifically addresses the harmful interactions during melt processing by providing both adhesion prevention and die build-up inhibition through its dual functionality of reducing interfacial tension and preventing polymer degradation adhesion.
Solution Approach 2:
The patent employs a composite recycling agent structure combining polyolefin-based resin backbone with grafted polar functional groups. This composite material approach allows the recycling agent to simultaneously interact with both non-polar thermoplastic resin and polar EVOH, creating a multi-functional protection against adhesion, die build-up, and fish eye generation that single-component agents cannot achieve.
2Object-generated harmful factors
If polyol is blended with acid grafted modified polyolefin-based resin, then adhesion problems are improved, but transparency is not sufficiently maintained
Solution Approach 1:
The patent changes the chemical parameters of the recycling agent by using polyolefin-based resin with specific grafted polar groups (carboxyl, hydroxyl, or amino groups) instead of conventional polyol blends. This parameter change maintains transparency by avoiding the crystallization and light scattering issues associated with polyol additives, while still providing the necessary adhesion prevention through the grafted functional groups that reduce interfacial tension between layers.
3Strength
If adhesive composition with ring opening polymer or condensation polymer is used, then adhesion to EVOH is improved, but it is not suitable as a recycling agent for melt processing
Solution Approach 1:
The patent changes the molecular weight and structural parameters of the adhesive composition by using polyolefin-based resin with grafted polar groups instead of conventional ring opening or condensation polymers. This parameter change maintains adequate adhesion to EVOH through the grafted functional groups while improving melt processability by reducing viscosity and ensuring compatibility with thermoplastic resin, making it suitable for recycling applications.
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 proposed solution effectively inhibits adhesion to screws, reduces die build-up, and maintains transparency in recycled multilayer structures, enhancing the recycling efficiency and quality of molded articles.
Implementation Method 1
a recycling agent containing a polymer (A) obtained by reacting a modified olefin-based polymer (a-1) with a polymer (a-2) containing a terminal functional group
Data Source
AI summary
A compatibilizer contains a polymer (A) obtained by reacting a modified olefin-based polymer (a-1) with a polymer (a-2) containing a terminal functional group, wherein the modified olefin-based polymer (a-1) is a polymer modified with from 0.01 to 2 mass% of unsaturated carboxylic acid or a derivative thereof, and the polymer (a-2) is a ring opening polymer or condensation polymer containing a terminal functional group, capable of reacting with the modified olefin-based polymer (a-1), at both ends or one end thereof and has a number average molecular weight from 1,500 to 100, 000. This provides an excellent compatibilizer. Particularly, upon melt processing a recovery of a multilayer structure including an EVOH layer and a thermoplastic resin layer, a recycling agent is provided that gives sufficient improvement effects to any of the adhesion of a degraded resin to a screw of a molding machine, the generation of die build-up, the generation of fish eyes, and the decrease in transparency.