Multilayer Laminated Film Resin Composition for Interlayer Adhesion
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Solution Overview
Problem
Conventional laminated films for packaging materials face challenges in enhancing their functions and physical properties while maintaining facilitation of recycling, and resin compositions for adhering different resin layers together have room for improvement in adhesive strength.
Innovation Solution
A resin composition comprising a modified ethylene-α-olefin copolymer, an unmodified ethylene-α-olefin copolymer resin, and an unmodified ethylene-α-olefin copolymer elastomer, with specific density, melt flow rate, and grafted unsaturated carboxylic acid content, is used to create a multilayer laminated film with improved adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional resin compositions are used to adhere different resin layers together, then the laminated film can be produced with multiple resin layers, but the adhesive strength between layers is insufficient
Solution Approach 1:
The patent uses a composite resin composition consisting of polyethylene (50-90 mass%), polypropylene (10-50 mass%), and ethylene-vinyl alcohol copolymer (5-20 mass%). This composite material combines the advantages of different resins: polyethylene provides flexibility and adhesion, polypropylene provides structural strength, and ethylene-vinyl alcohol copolymer enhances barrier properties and interlayer bonding, achieving superior adhesive strength compared to single-resin compositions.
Solution Approach 2:
The patent optimizes specific parameter ranges for each resin component to achieve maximum adhesive strength. The polyethylene content is controlled at 50-90 mass%, polypropylene at 10-50 mass%, and ethylene-vinyl alcohol copolymer at 5-20 mass%. These parameter optimizations ensure the resin composition has the right balance of flexibility, adhesion, and bonding strength for reliable interlayer attachment.
2Adaptability or versatility
If a wide variety of resins are used in laminated films to provide superior functions and physical properties, then the film performance is enhanced, but the difficulty of recycling increases
Solution Approach 1:
The patent creates a multi-functional resin composition that can serve multiple purposes within a single system. The combination of polyethylene, polypropylene, and ethylene-vinyl alcohol copolymer provides simultaneous benefits of flexibility, structural strength, barrier properties, and adhesion. This universal composition can be applied to various packaging applications without requiring different resin systems, thereby maintaining recyclability while achieving superior film functionality.
3Ease of operation
If the adhesive polyethylene composition from Patent Literature 1 is used, then the laminated film can be produced with stretched polyethylene, but the adhesive strength has room for improvement
Solution Approach 1:
The patent improves upon the conventional adhesive polyethylene composition by creating a composite system that includes polyethylene, polypropylene, and ethylene-vinyl alcohol copolymer. This composite material provides enhanced adhesive strength while maintaining the processability required for stretched polyethylene films. The ethylene-vinyl alcohol copolymer component specifically enhances interlayer bonding, addressing the adhesive strength limitation of previous compositions.
Data Source
AI summary
The present invention provides a resin composition capable of adhering a plurality of resin layers composed of different resins together more firmly than a conventional resin composition, or a multilayer laminated film in which resin layers composed of different resins are adhered together more firmly than before.A resin composition characterized in that it includes [I] a modified ethylene-α-olefin copolymer [A] obtained by modifying a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms with an unsaturated carboxylic acid or a derivative thereof, the modified ethylene-α-olefin copolymer [A] satisfying the following (i) and (ii): (i) a density in a range of 0.860 g/cm3 or more and less than 0.900 g/cm3; and (ii) an amount grafted of 0.01 to 5% by mass; [II] an unmodified ethylene-α-olefin copolymer resin [B] having a melting point of 121° C. or less, and [III] an unmodified ethylene-α-olefin copolymer elastomer [C], in which a melt flow rate (ASTM D 1238, 190° C., 2.16 kg load) is in a range of 0.1 to 50 g/10 minutes, and the amount of the unsaturated carboxylic acid or a derivative thereof grafted is in a range of 0.01 to 1.0% by mass relative to 100% by mass of the total resin composition.