This article provides a clear overview of the characteristics, manufacturing methods, suitable applications, and precautions associated with OPA film.
What is OPA Film?
Films primarily made from polyamide (nylon-6) resin, is categorized into non-oriented polyamide film and biaxially oriented polyamide film (OPA film). It sometimes called “ONY” (Oriented Nylon) film, derived from the brand name of polyamide resin “Nylon”.
OPA film is known for its toughness and resistance to pinholes, making it suitable for packaging liquids.
With a melting point of 190°C, it cannot be heat-sealed and is typically used in laminated form. It has relatively good printability and lamination properties.
Manufacturing Methods:
There are three main methods for producing biaxially oriented polyamide film:
1. T-die Sequential Biaxial Orientation
Figure 1. Schematic Diagram of T-Die Sequential Biaxial Orientation
2. T-die Simultaneous Biaxial Orientation
Figure 2. Schematic Diagram of T-Die Simultaneous Biaxial Orientation
3. Tubular Simultaneous Biaxial Orientation
Figure 3. Schematic Diagram of Tubular Simultaneous Biaxial Orientation
Each method has its advantages and disadvantages. Toyobo has adopted the sequential biaxial stretching method and has continuously improved its technology to produce high-quality films.
Physical Properties:
OPA film has several excellent properties:
- Toughness
- Pinhole resistance
- Abrasion resistance
- Gas barrier properties
- Heat and cold resistance
- Non-toxic and odorless
- Good ink and lamination adhesion
One of the weaknesses is that moisture absorption can cause dimensional changes and a decrease in stiffness. Additionally, extreme reductions in impact strength due to moisture and heat must be noted.
Figure 5 shows the relationship between humidity during film storage and the dimensional change rate of OPA film. Higher humidity in the storage location leads to greater elongation of the nylon film due to moisture absorption.
Figure 6 shows the puncture strength of 15μm OPA film after retort processing under specified temperature conditions.
Due to the strength reduction caused by moisture and heat treatment, it is common to laminate PET film on the outermost layer when using OPA film for applications involving severe moisture and heat treatment, such as retort processing.
Figure 5. Relationship between Humidity during OPA Film Storage and Dimensional Change Rate
(Measured by TOYOBO CO., LTD.)
Figure 6. Relationship between Retort Processing Conditions and Puncture Strength of 15μm OPA Film
(Measured by TOYOBO CO., LTD.)
Applications:
Due to these properties, OPA film is used in various applications requiring strong packaging, such as liquid food packaging, retort food pouches, and refill pouches.
Table 1. Main Applications and Required Properties of OPA Films
In addition to the standard type, Toyobo offers a wide range of products with various functionalities, such as improved pinhole resistance, enhanced water adhesion, and environmentally friendly options.
If you have any questions, please do not hesitate to contact us!
＊Please note that the data provided are reference values and not guaranteed values.
