Multi-layer cling film LLDPE HDPE composition
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Solution Overview
Problem
Current cling films for food sealing and protection face challenges in achieving good cling performance while being easy to cut and having good machinability, which is essential for applications like fast wrappers.
Innovation Solution
A multi-layer film composition with at least three layers, featuring two outer layers comprising 73-99.5 wt.% LLDPE and 0.5-7 wt.% HDPE, optionally with anti-fog agents, and a core layer with a higher percentage of LLDPE, enhancing cling performance and machinability by reducing friction and minimizing substance leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cling film is made from traditional materials like PVC or LDPE/LLDPE/EVA blends, then good cling performance can be achieved, but the film has poor machinability and is difficult to cut
Solution Approach 1:
The film is divided into multiple functional layers with distinct compositions: an outer LLDPE layer for machinability and cutting ease, and an inner PVC layer for cling performance. This segmentation allows each layer to optimize its specific function without compromising the other, resolving the contradiction between cling performance and machinability.
Solution Approach 2:
The invention uses a composite multi-layer structure combining different polymer materials (LLDPE and PVC) with complementary properties. The LLDPE outer layer provides ease of cutting and machinability, while the PVC inner layer delivers superior cling performance, creating a composite material system that achieves both previously conflicting requirements.
2Reliability
If the film composition is optimized for cling performance similar to PVC, then good sealing properties are achieved, but the mechanical properties for fast wrapper applications are compromised
Solution Approach 1:
The film structure segments mechanical strength requirements from cling performance requirements. The outer LLDPE layer provides the necessary mechanical strength and toughness for fast wrapper applications, while the inner PVC layer specifically addresses cling performance, allowing both properties to be optimized independently.
Solution Approach 2:
By combining LLDPE and PVC in a multi-layer composite structure, the film achieves a balance of mechanical properties and cling performance. The LLDPE layer contributes tensile strength and puncture resistance needed for mechanical handling, while the PVC layer provides the adhesive cling properties, creating a composite material with balanced performance characteristics.
Data Source
AI summary
The present invention concerns a multi-layer film for cling film applications comprising at least three layers, with two outer layers, at least one core layer, preferably exactly one core layer, wherein at least one or both outer layer(s) comprise(s) between 73 wt. % and 99.5 wt. % or between 73 wt. % and < 99.5 wt. % of LLDPE based on the total weight of the respective layer and between 0.5 wt. % and 7 wt. % of HDPE based on the total weight of the respective layer.