How does the moisture vapor transmission rate affect the products wrapped in stretch film?

As a stretch film supplier, I've witnessed firsthand the pivotal role that the moisture vapor transmission rate (MVTR) plays in the performance and integrity of products wrapped in stretch film. MVTR refers to the rate at which water vapor permeates through a material over a given period under specific conditions. Understanding how MVTR affects products is crucial for ensuring their quality, safety, and longevity. In this blog post, I'll delve into the science behind MVTR and explore its implications for various products wrapped in stretch film.

The Science of Moisture Vapor Transmission

Moisture vapor transmission is a natural process driven by the difference in water vapor pressure between two sides of a material. When there is a higher concentration of water vapor on one side of the stretch film compared to the other, water molecules will move from the area of higher concentration to the area of lower concentration. This movement occurs through tiny pores or gaps in the film structure, and the rate at which it happens is determined by several factors, including the film's composition, thickness, temperature, and humidity.

The MVTR of a stretch film is typically measured in grams per square meter per day (g/m²/day). A lower MVTR indicates that the film is more resistant to moisture vapor transmission, while a higher MVTR means that the film allows more water vapor to pass through. Different applications require different levels of moisture protection, and choosing the right stretch film with an appropriate MVTR is essential for achieving the desired results.

Impact on Food Products

One of the most significant applications of stretch film is in the food industry, where it is used to wrap and preserve a wide range of products, including fresh produce, meats, cheeses, and bakery items. Moisture is a critical factor in food quality and safety, as it can affect the texture, flavor, and shelf life of the products.

Fresh Produce: Fruits and vegetables are highly perishable and require a delicate balance of moisture to stay fresh. A stretch film with a low MVTR can help to retain the natural moisture of the produce, preventing it from drying out and wilting. This not only extends the shelf life of the products but also maintains their appearance and nutritional value. On the other hand, a film with a high MVTR may allow too much moisture to escape, leading to shrinkage, loss of flavor, and increased susceptibility to spoilage.

Meats and Cheeses: Meats and cheeses are also prone to moisture loss and spoilage if not properly protected. A stretch film with a low MVTR can create a barrier against oxygen and moisture, preventing the growth of bacteria and mold. This helps to maintain the freshness and quality of the products, as well as their color and texture. Additionally, a good quality stretch film can prevent the formation of freezer burn when meats and cheeses are stored in the freezer.

Bakery Items: Bakery items, such as bread, cakes, and pastries, are sensitive to moisture and can quickly become stale if exposed to the air. A stretch film with a low MVTR can help to keep the bakery items fresh and moist, extending their shelf life and improving their taste. It can also prevent the growth of mold and other contaminants, ensuring the safety of the products.

Impact on Industrial Products

In addition to food products, stretch film is widely used in the industrial sector to protect and secure a variety of goods during storage and transportation. The MVTR of the stretch film can have a significant impact on the performance and durability of these products.

Electronics: Electronics are highly sensitive to moisture, which can cause corrosion, short circuits, and other damage. A stretch film with a low MVTR can provide a protective barrier against moisture, preventing it from reaching the electronic components. This helps to ensure the reliability and functionality of the electronics, as well as their longevity.

Metals: Metals are prone to rust and corrosion when exposed to moisture. A stretch film with a low MVTR can help to prevent the formation of rust by creating a barrier against oxygen and moisture. This is particularly important for metal products that are stored outdoors or in humid environments.

Textiles: Textiles can absorb moisture, which can lead to mold growth, mildew, and unpleasant odors. A stretch film with a low MVTR can help to keep the textiles dry and prevent the growth of mold and mildew. This is especially important for textile products that are stored for long periods or in damp conditions.

Choosing the Right Stretch Film

When selecting a stretch film for a specific application, it's important to consider the MVTR of the film, as well as other factors such as strength, puncture resistance, and cling properties. Here are some tips to help you choose the right stretch film:

• Understand the Application: Determine the specific requirements of your application, including the type of product being wrapped, the storage and transportation conditions, and the desired level of moisture protection.
• Consider the MVTR: Choose a stretch film with an appropriate MVTR based on the moisture sensitivity of the product. For products that require high levels of moisture protection, such as food and electronics, a film with a low MVTR is recommended.
• Evaluate Other Properties: In addition to the MVTR, consider other properties of the stretch film, such as strength, puncture resistance, and cling properties. These properties can affect the performance and durability of the film.
• Test the Film: Before making a large purchase, it's a good idea to test the stretch film on a small scale to ensure that it meets your requirements. This can help you to avoid any potential issues and ensure that you are getting the best product for your needs.

Our Stretch Film Products

At our company, we offer a wide range of stretch film products with different MVTRs to meet the diverse needs of our customers. Our Surface Guard Adhesive Masking Film is a high-quality stretch film that provides excellent moisture protection and adhesion. It is ideal for protecting surfaces during painting, sanding, and other construction activities. Our LDPE Protective Film is a low-density polyethylene film that offers good clarity and flexibility. It is suitable for a variety of applications, including food packaging, electronics protection, and industrial wrapping. Our Blue PE Protection Film is a blue-colored polyethylene film that provides excellent UV protection and moisture resistance. It is commonly used for outdoor applications, such as protecting building materials and equipment.

Conclusion

The moisture vapor transmission rate (MVTR) of a stretch film is a critical factor that can significantly affect the performance and integrity of the products wrapped in it. Whether you are in the food industry, the industrial sector, or any other field that requires moisture protection, choosing the right stretch film with an appropriate MVTR is essential for ensuring the quality, safety, and longevity of your products. At our company, we are committed to providing high-quality stretch film products that meet the diverse needs of our customers. If you have any questions or need help selecting the right stretch film for your application, please don't hesitate to contact us. We look forward to working with you and helping you find the best solution for your moisture protection needs.

References

• ASTM International. (2023). Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor. ASTM F1249-23.
• European Committee for Standardization. (2016). Plastics - Film and sheeting - Determination of water vapour transmission rate - Part 1: Humidity detection sensor method. EN ISO 15106-1:2016.
• Smith, J. (2022). The Importance of Moisture Vapor Transmission Rate in Stretch Film. Packaging World.