Nylon film, commonly known as polyamide, is a molecular chain consisting of the repeat structure unit of the amide group (-CONH-) polymer, called nylon. Polyamide is called polyamide, or PA for short, and biaxially oriented polyamide (nylon) film, or BOPA. PA6 and PA66 are commonly used in the manufacture of films. Because PA66 crystallizes very quickly and is difficult to process, PA6 is commonly used.
Nylon films are synthetic thermoplastics with exceptionally high tensile strength, minimal tissue reaction, and a high degree of elasticity. Polyamides are considered to be some of the most powerful synthetic textile materials with excellent durability and low cost. That’s why nylon films have unique oxygen barrier properties, making them perfect for cooking applications and packaging materials.
What is BOPA Film?
BOPA film or Biaxially Oriented Polyamide film is a type of nylon film which is processed by a method called biaxial orientation. Also known as BON or Biaxially Oriented Nylon film. Biaxial orientation words refer to a method in which nylon film is stretched in a unique way that changes the orientation of its polymeric chains. As a result, the orientation of the films becomes parallel to the plane of the film. These changes provide BOPA films with exceptional clarity, enhancing their elasticity and tensile properties.
The chemical composition of BOPA film forms an amide group known for solid intermolecular adhesion due to hydrogen bonds. Therefore, BOPA film’s benefits are attributed to these strong molecular forces.
BOPA Films Classification:
Based on the structure, BOPA films are classified into two main categories:
- Specialty Films
- Plain Films
The main difference between these two types is the number of layers in each type. For example, specialty films are made with several polymer layers between two and seven.
Based on appearance, BOPA films are grouped into:
- Transparent Films
- Metalized Films
Transparent Films: Most modern packaging materials for perishable goods use transparent films. They are clean and hygienic and package materials such as foodstuffs, vegetables, electronic devices, and medical and pharmaceutical products.
Metalized Films: Metalized films are BOPA films treated with a process called vacuum deposition. In this process, a thin layer of aluminum metal accumulates on the surface of the film. Metal films make the best alternative to aluminum foils and CPP films. They are widely used in food packaging.
BOPA Film Properties:
BOPA film has excellent properties and can be used for a variety of advanced packaging.
- Too much mechanical strength gives these films extraordinary hardness and makes them extremely hard.
- High mechanical strength
- Excellent flexibility and tensile strength
- The higher the melting point, the higher the heat resistance.
- Low elongation makes them difficult to pull and break.
- High puncture resistance
- Remarkable thermoformability
- Great printability
- Transparency
- Aesthetically pleasing, glossy finish
Unlike standard nylon film, BOPA film does not degrade under load due to its flexible properties. Because of these properties, BOPA films are considered one of the most sought-after specialty films and are used as a flexible packaging solution for oxygen-sensitive foods.
Actually, this film is just hard to use. It is usually coated with other materials (such as PE, EVA, PET, CPP aluminum foil and paper, etc.) for better composite performance.
Benefits of BOPA Film:
- It has a wide range of temperature applications (-60℃- 150℃) and is a good barrier against oxygen, nitrogen, carbon dioxide and odor. It is resistant to acids, alkaline, fats and various common organic solvents. BOPA also has high transparency and gloss. It is used for food packaging and is used in printing and laminating processes.
- High demand for ready-to-eat foods, processed foods, and canned fruits and vegetables are likely to persist in the use of BOPA films as consumer safety will be a priority.
- Improvements in the mechanical, optical and barrier properties of oriented films have strengthened the use of BOPA in pharmaceutical packaging. Biaxially-oriented polyamide films offer high performance and high resistance to oxygen and moisture even at low thicknesses, making them a good choice among food providers.
BOPA Film Application
BOPA films are widely used in the food packaging industry, thanks to their oxygen and odor-resistant properties. Some common processed foods packaged with BOPA films include:
- General Food
- Cheese and Other Dairy Products
- Highly Prepared Microwaveable Food Frozen Foods and Vegetables
- Detergents
- Retort
- Pharmaceutical products
- Personal care
- Balloons
- Electronics Devices
- Agricultural Products
- Aquatic Products
In addition, BOPA film is widely used in medical, pharmaceutical equipment, cosmetics and machinery, electronics and other general industrial packaging fields.
Now come to the identification of the nylon.
Nylon is identified by a number – such as 6 or 66 – which refers to the number of carbon atoms between the amine and acid groups, as well as the formation of the polymer. For example, Nylon 6 is made entirely of a single monomer, while Nylon 66 is made of a combination of different monomers (called comonomers). Nylon can also be reinforced with additional materials such as glass or combined with other engineering plastics to enhance performance and material properties.
The three most common types of nylon are Nylon 6, Nylon 66, and PA12.
Nylon 6 filaments are highly flexible fibres that are often used in textile and high-strength industrial applications, including apparel, ropes and industrial cords. These fibres have a smooth, glass-like surface that offers excellent abrasion resistance. Nylon 6 is usually the result of a more reliable final part dimension.
Nylon 66 Nylon has more than 6 crystalline materials and therefore provides more rigidity, tensile modulus, and flexible modules. This makes it an ideal material for applications that require strength, hardness, and chemical resistance, such as carpets, airbags, and luggage.
PA 12 (also called Nylon 12) is a good plastic for general use with a wide range of additional applications and is known for its stiffness, tensile strength, impact strength and ability to bend without fractures. PA 12 has long been used by injection moulders because of its mechanical properties.
Why Nylon?
Nylon is highly valued for its combination of natural low friction properties and strong mechanical, chemical and thermal properties. It is a versatile and high-performance family of materials suitable for applications that are subject to high wear and tear, such as fuel system components, manifolds, brackets, gears, and other applications, that require high melting temperature plastic material. Nylon can also be combined with additional accessories and stabilizers, enabling greater quality and control while improving the material properties of different components.
Furthermore, since nylon can be shaped into filaments, fibres, films, and sheets, and can be used in conjunction with a number of manufacturing processes – including injection moulding, CNC machining, and 3D printing – these materials are often used for prototyping purposes.
Over the years, the demand for biaxially-oriented polyamide (BOPA) film has increased due to increasing demand in food packaging and its superior protective properties, such as deodorant, water vapour, and increasing barrier functions, Shelf life, and retaining flavour. Biaxially-oriented polyamide (BOPA) film is used in a variety of end-use industries.
