Machine-direction orientation (MDO) film is made where, a polymer film is heated to a temperature slightly below its melting point and stretched in a particular orientation. The film can be cast on an MDO machine, or this step introduced as the last stage in the manufacture of blown films.
Benefits of MDO Film?
Less raw material used, leading to reduced mass and lower transportation costs
Improves company’s green credentials by shrinking carbon footprint
Improved mechanical properties, including puncture resistance and easy tearing in a particular direction
Film can be tailored to specific requirements, such as low or high gloss, polarisation, or haze
Other uses of MDO technology
Because the process also confers resistance to moisture, MDO products are not only used as packing materials, but as the impermeable layer in nappies, sanitary products and incontinence pads.
Some of the films are even made from natural biodegradable compounds.
Despite these applications, the manufacturing process is challenging. It consists of four separate stages, and selecting the wrong settings at any one of them can produce a film that is too brittle. MDO sounds simple, but works profound changes on the properties of the material treated.
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The challenges surrounding MDO
Nowadays, issues arise because the equipment used to produce MDO film has an almost infinitely varied number of settings. This level of flexibility is an asset, but it requires expert operators who have enough experience to possess a feel for the likely outcome whenever variables are changed.
Also, operators need to know their materials, since the draw ratio for the finished film depends upon the original polymer. Some materials cannot be MD oriented at all because their composition results in a film with very poor tensile strength.
MDO film is one of this century’s engineering triumphs. The process not only results in the decreased use of raw materials and improved transportation costs, but produces films with varied mechanical and optical properties, making them suitable for purposes from nappies to synthetic woven sacking. As MDO technology and materials science advances, expect this indispensable process to dominate industry to an ever greater extent in the future.
