What is Nylon?

The Advantages of Nylon Films

Nylon film, renowned for its exceptional properties, stands as a versatile material in the realm of packaging.

Its notable characteristics include flexibility, toughness, and impermeability, making it a preferred choice for various applications.

Nylon’s resilience plays a crucial role in preventing breakage, particularly in products prone to impact. Commonly utilized in structures like NY/PE and PET/NY/PE, it finds its place in diverse packaging solutions, ranging from vacuum packaging to heavy-duty applications.

Whether enhancing the shelf life of food products or providing crucial impact resistance, nylon film continues to be a key player in the evolution of modern packaging.

Nylon films offer several significant advantages:

• Flexibility and Toughness:
  Nylon films are highly flexible and durable, providing flexible packaging with elevated strength and resistance to breakage.
• Environmentally Friendly:
  They are eco-friendly and recyclable, avoiding the generation of harmful chemical pollutants in the environment.
• Cost-Effective:
  Nylon films are a relatively inexpensive synthetic material.
• Impermeability:
  Nylon films are impermeable, making them ideal for food packaging as they prevent the entry of air, preventing packaging expansion.
• Ease of Recycling and Microwavability: Nylon films are easily recyclable and compatible with microwave usage.
• Wide Range of Applications in Food Packaging:
  Nylon films are extensively used in food packaging due to their versatility, and applicability to various materials.
• Enhanced Peel Strength:
  Using nylon in packaging increases peel strength, preventing delamination.
• Aluminized nylon:
  Aluminized nylon (TNY) enhances film barrier properties, making it suitable for high-barrier product bags.

The Weakness of Nylon Films

• Hygroscopic Nature:
  Nylon film is highly prone to absorbing moisture and alcohol, with a saturation level reaching 8–9%.

  This can affect dimensional stability and reduce the mechanical performance of the film. Once nylon film absorbs moisture, it changes, becoming soft, wrinkled, and deformed.

  It is recommended to dry the nylon film in a curing room at 45–50°C for 1–2 hours before use.

  During humid or colder weather, activating the preheating system is essential to remove the moisture from the BOPA film.

  If the nylon film absorbs too much moisture and becomes soft and wrinkled, it should not be used, as this can lead to quality issues.

  The moisture content of the film should not be overlooked.

  Before production, check the film’s moisture content; if it exceeds 3%, it should be carefully dried before use.

  Additionally, the A adhesive in solvent-free glue contains -NCO, which easily reacts with moisture in the air. If the film’s moisture content is too high, it will negatively impact the bonding quality.

• Bow Effect:
  The bow effect is a unique defect of nylon film.

  It occurs in both synchronous and step-by-step production processes, although the bowing degree may vary. 

  The larger the bow angle, the greater the balance shrinkage rate, with a rate of 1.5% indicating minimal shrinkage and fewer premium-grade products.

• Importance of Film Moisture Content and Workshop Temperature/Humidity Control:
  Monitoring the workshop’s humidity and dew point is crucial. Any condensation should be wiped off promptly.Typically, the production environment should maintain a temperature of 23°C ± 3°C and a humidity level of 60% ± 5%.

  If the humidity exceeds 75% RH, pausing or stopping composite production is recommended.

  If water droplets are found on the ink knife, guide roller, or adhesive roller, they should be wiped off immediately to prevent the nylon film from absorbing more moisture.

• Moisture-Heat Shrinkage and Static Properties:
  For PA film used in boiling and retort bags, the moisture-heat shrinkage should be minimized, and the film’s longitudinal and transverse shrinkage difference should not exceed 0.5%.
• Barrier Properties:
  Due to PA film’s high hygroscopicity, it is generally not included in the moisture absorption calculation.

  However, different manufacturers use different PA materials, resulting in varying moisture absorption rates. 

  It is important to select materials with lower hygroscopicity.

  Oxygen barrier properties are a crucial factor for nylon films.

  In addition to national standard testing, high-barrier nylon products should also be tested under high-barrier standards.

  For retort bags or films used as middle layers, ensure their barrier properties are tested at 80% RH humidity.

• Light Resistance:
  BOPA film has poor light resistance.

  In high-temperature environments, it reacts with oxygen in the air, turning yellow-brown and eventually breaking down. 

  It is also not resistant to strong acids and oxidizers, and therefore cannot be used as acid-resistant material.

Flexible Packaging Usages of Nylon Films

The versatility of nylon films makes them widely applicable to various flexible packaging, including both food and non-food packaging. When our products require protection against impact and breakage, Nylon (NY) is a preferred choice.

• Its toughness plays a crucial role in preventing package breakage when products are dropped, making it a common structural choice for household products like laundry detergent, that is NY/PE.
• For conventional food packaging, such as snacks, PET/NY/PE structures are typically selected.
• For retort products and sauces that require high-demand packaging, Nylon is often used to enhance packaging toughness and product protection. PET/AL/NY/RCPP is a commonly utilized material structure.
• For products with a critical need for impact resistance, especially in heavy-duty packaging, double-layered Nylon protection (NY/NY/PE) becomes essential.
• In the case of Bag-in-Box (BIB) packaging, the inclusion of NY in NY/PE&PE structures also provides crucial impact resistance.
• Vacuum packaging also often selects nylon (NY) materials. NY/PE and PET/NY/PE are commonly used structures.
• When high barrier properties are required, aluminum (AL) is a preferred choice, but due to cost considerations, Alox-Nylon becomes an excellent alternative.
• Nylon can be selected for almost any flexible packaging structure except single material ones.