Ethylene/Alkylacrylate Tie-Layer for PET Film Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tie-layer materials in multilayer films for packaging, such as PET/tie/PE structures, face challenges with adhesion properties, particularly at high temperatures and are prone to negative taste and odor issues, which affect the film's performance and processing stability.
Innovation Solution
A film configuration comprising a first layer of polyester or polylactic acid and a second layer formed from a functionalized ethylene-based polymer and ethylene/alkylacrylate copolymer, with specific weight ratios and melt indices, enhancing adhesion and thermal stability while minimizing taste and odor concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional tie-layer materials (maleic anhydride modified ethylene methylacrylate or ethylene vinyl acetate polymers) are used to provide interlayer adhesion, then adhesion properties between PET and polyolefin layers are improved, but taste and odor properties deteriorate and thermal stability at high processing temperatures (≥ 225°C) is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the tie-layer by using ethylene/alkylacrylate copolymers with specific alkyl group configurations (methyl, ethyl, propyl, or butyl) and controlled comonomer content (5-30 mol%). This parameter change eliminates the taste and odor issues associated with conventional materials while maintaining adhesion properties through the carbonyl groups formed by alkylacrylate units.
Solution Approach 2:
The patent creates a composite tie-layer system combining ethylene/alkylacrylate copolymer with specific functional groups that provide both adhesion to polyester and polyolefin layers. The composite nature of the copolymer, with ethylene providing polyolefin compatibility and alkylacrylate providing carbonyl groups for polyester adhesion, resolves the contradiction between adhesion and taste/odor properties.
2Strength
If conventional tie-layer materials are used to provide interlayer adhesion, then adhesion properties between PET and polyolefin layers are improved, but thermal stability at high processing temperatures (≥ 225°C) deteriorates
Solution Approach 1:
The patent changes the thermal stability parameters by selecting alkylacrylate copolymers with higher thermal resistance compared to vinyl acetate or methylacrylate. The specific alkyl group selection and comonomer content control the glass transition temperature and melting point, ensuring thermal stability at processing temperatures ≥ 225°C while maintaining adhesion through carbonyl functionality.
3Strength
If multilayer film structures with multiple tie-layers are used to ensure adhesion between outer/inner layers and barrier layers, then adhesion properties are improved, but device complexity increases
Solution Approach 1:
The patent makes the tie-layer material universal by designing ethylene/alkylacrylate copolymers that can adhere to multiple different layers (PET, PA, EVOH, polyolefins) simultaneously. The copolymer's dual compatibility—ethylene providing polyolefin affinity and alkylacrylate carbonyl groups providing polyester/polyamide affinity—allows a single tie-layer composition to replace multiple specialized tie-layers, reducing structural complexity.
Data Source
Figure 1~2
Figure 3
AI summary
The invention provides a film comprising at least two layers, a first layer and a second layer; and wherein the first layer is formed from a first composition comprising a polyester and/or a polylactic acid; and wherein the second layer is formed from a second composition comprising at least the following: A) a functionalized ethylene-based polymer, and B) at least one ethylene/alkylacrylate copolymer.