Machine Direction Oriented Multilayer Film for Labels
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Solution Overview
Problem
Current label films lack optimal mechanical, optical, and recyclable properties, particularly in terms of stiffness, conformability, printability, and down-gauging, while maintaining transparency and ease of dispensing.
Innovation Solution
A machine direction oriented multilayer film comprising a bimodal ethylene/1-butene/C6-C12-alpha-olefin terpolymer core layer sandwiched between two high-density polyethylene (HDPE) outer layers, which is uniaxially oriented in the machine direction, enhancing mechanical and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-oriented blown or cast PE films are used, then flexibility and conformability are achieved, but optical clarity deteriorates and register control in printing worsens
Solution Approach 1:
The patent applies machine direction orientation (MDO) to change the physical structure of the film by stretching it in the machine direction, which improves optical clarity and print register control while maintaining conformability through controlled uniaxial orientation
Solution Approach 2:
The patent uses a multilayer film structure combining different polymer layers (LLDPE and HDPE) with specific properties to achieve both optical clarity and conformability that single-layer films cannot provide
2Quantity of substance
If film thickness is reduced for down-gauging, then cost-effectiveness improves, but mechanical strength and stiffness deteriorate
Solution Approach 1:
The patent uses machine direction orientation to change the molecular alignment and physical structure of the film, enabling thin films to achieve high stiffness and strength properties that would normally require much thicker material
Solution Approach 2:
The patent applies different polymer types and properties to different layers of the multilayer structure, with outer layers providing strength and the core layer providing flexibility, optimizing mechanical properties at reduced thickness
3Illumination intensity
If machine direction orientation is applied, then optical clarity and stiffness improve, but transverse direction flexibility deteriorates
Solution Approach 1:
The patent controls the orientation process to achieve uniaxial machine direction orientation rather than biaxial orientation, which improves optical clarity while preserving transverse flexibility needed for conformability
Solution Approach 2:
The multilayer structure with different polymer compositions in outer and core layers compensates for the loss of transverse flexibility caused by MDO, maintaining overall conformability
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 film achieves improved stiffness, conformability, printability, and recyclability, allowing for thinner, more cost-effective labels with better dispensing and optical clarity, suitable for various labeling applications including pressure-sensitive and heat shrink sleeve labels.
Implementation Method 1
These rolls are heated sufficiently to bring the film to a suitable temperature. Under these conditions, the film is stretched in the machine direction. Then the film is rapidly cooled to set the orientation of the film.
Implementation Method 2
a core layer (C) of a bimodal terpolymer, e.g. a bimodal ethylene/1-butene/C6-C12-alpha-olefin terpolymer
Implementation Method 3
two outer layers (O-1, O-2) of HDPE
Data Source
AI summary
Machine direction oriented multilayer film suitable for preparing labels, comprising a core layer of a bimodal terpolymer and two outer layers comprising HDPE.