Polyamide Film Composition for Recyclable Gel-Free Laminates
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Solution Overview
Problem
Existing polyamide resin compositions for packaging materials face issues with recyclability, transparency, mechanical strength, and pinhole resistance, particularly when combined with different resin layers, leading to film gel formation and reduced functionality.
Innovation Solution
A polyamide resin composition comprising 88 to 99% aliphatic polyamide resin, 1 to 5% functional group-containing ethylene/α-olefin copolymer, and 0 to 9% other components, with specific molecular ratios and properties, allowing for improved compatibility and recyclability without film gel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If different resins are mixed for recycling without peeling layers, then recycling process is simplified, but physical properties of recycled resin significantly deteriorate
Solution Approach 1:
A compatibilizer comprising a polyolefin resin and a specific amount of modified polyolefin resin (1-10 parts by mass per 100 parts of polyolefin resin) is introduced as an intermediary substance between polyamide and polyolefin layers. This compatibilizer improves interlayer adhesion and maintains physical properties of recycled resin while enabling direct recycling without layer separation.
Solution Approach 2:
The invention optimizes the ratio of modified polyolefin resin to polyolefin resin within a specific range (1-10 parts by mass per 100 parts). By controlling this parameter, the composition achieves balanced compatibility between polyamide and polyolefin layers, preventing both excessive softening and property deterioration in recycled materials.
2Stability of the object's composition
If compatibilizer is added to mix different resins, then compatibility between layers is improved, but film gel formation increases and transparency deteriorates
Solution Approach 1:
The invention precisely controls the content of modified polyolefin resin within 1-10 parts by mass per 100 parts of polyolefin resin. This parameter optimization ensures sufficient compatibility between layers while preventing excessive compatibilizer content that would cause film gel formation and transparency deterioration.
Solution Approach 2:
The compatibilizer is specifically designed with localized functionality: the modified polyolefin resin provides compatibility at the interface between polyamide and polyolefin layers, while the base polyolefin resin maintains the overall film structure and optical properties. This localized quality distribution prevents film gel formation.
3Strength
If aliphatic copolymer polyamides are used to impart flexibility, then elasticity is improved, but pinhole resistance and transparency deteriorate
Solution Approach 1:
The invention optimizes the ratio of aliphatic homopolyamide to aliphatic copolymer polyamide within a specific range (20-80 mass% homopolyamide). This parameter control balances flexibility from copolymer segments with pinhole resistance and transparency from homopolyamide segments.
Solution Approach 2:
The polyamide resin composition is designed as a composite of aliphatic homopolyamide and aliphatic copolymer polyamide. This composite structure combines the advantages of both components: homopolyamide provides pinhole resistance and transparency, while copolymer polyamide contributes flexibility and elasticity.
4Adaptability or versatility
If high content of polyolefin resin is used for compatibility, then recyclability is improved, but mechanical strength of the composition deteriorates
Solution Approach 1:
The invention optimizes the ratio of polyolefin resin to polyamide resin within 5-50 parts by mass per 100 parts of polyamide resin. This parameter range ensures sufficient recyclability and compatibility while maintaining mechanical strength through adequate polyamide content.
Solution Approach 2:
The modified polyolefin resin acts as a compatibilizer that enables effective mixing of polyolefin and polyamide resins. This intermediary substance allows higher polyolefin content for recyclability while maintaining mechanical properties through improved interfacial adhesion.
Data Source
AI summary
There are provided a polyamide resin composition that provides a film which is free from appearance deterioration due to film gels, and exhibits excellent transparency, mechanical strength and pinhole resistance, and whose material recycling is possible, as well as a film and film laminate using the same. The polyamide resin composition containing 88 to 99 mass% of an aliphatic polyamide resin (A), 1 to 5 mass% of a functional group-containing copolymer (B) of ethylene and an α-olefin having 3 to 8 carbon atoms, and 0 to 9 mass% of other components (C) based on 100 mass% of the polyamide resin composition. In the component (A), a ratio of the number of methylene groups to the number of amide groups is 3 to 11, and the component (A) (100 mass%) contains 1 to 50 mass% of an aliphatic homopolyamide (A-1) and 50 to 99 mass% of an aliphatic copolymer polyamide (A-2). A DSC curve of the resin composition has a melting peak at 150 to 205°C. A number average molecular weight Mn of the resin composition is 50,000 to 60,000. When the polyamide resin composition of the present invention or the film using the same is recycled, it is possible to contribute to achievements of Goals 13 and 14 of the Sustainable Development Goals (SDGs).