What is the light transmittance of BOPP film?
As a supplier of BOPP (Biaxially Oriented Polypropylene) film, I often receive inquiries about the light transmittance of this versatile material. Light transmittance is a crucial property that significantly influences the performance and suitability of BOPP film in various applications. In this blog, I'll delve into what light transmittance is, how it's measured, and the factors affecting the light transmittance of BOPP film, along with its implications for different uses.
Understanding Light Transmittance
Light transmittance refers to the proportion of incident light that passes through a material. It is usually expressed as a percentage. For instance, if a BOPP film has a light transmittance of 92%, it means that 92% of the light hitting the film passes through it, while the remaining 8% is either absorbed or reflected. This property is of great importance as it can determine the visual appearance and functionality of products made from BOPP film.
Measuring Light Transmittance
The light transmittance of BOPP film is typically measured using a spectrophotometer. This instrument emits light of a specific wavelength (usually in the visible light range, around 400 - 700 nanometers) onto the film sample and then measures the amount of light that passes through it. The ratio of the transmitted light intensity to the incident light intensity is calculated to obtain the light transmittance percentage.
Factors Affecting the Light Transmittance of BOPP Film
- Film Thickness: Generally, thinner BOPP films tend to have higher light transmittance. As the thickness of the film increases, there is a greater chance for light to be absorbed or scattered within the material, resulting in a lower percentage of transmitted light. For example, a very thin BOPP film with a thickness of 15 microns may have a light transmittance close to 95%, while a thicker film of 60 microns might have a transmittance of around 90%.
- Additives and Fillers: The addition of certain additives and fillers to the BOPP film can have a significant impact on its light transmittance. Anti - blocking agents, which are used to prevent the film from sticking to itself during storage and processing, can sometimes cause light scattering. Similarly, colorants or UV stabilizers can absorb light, reducing the overall transmittance. Clear BOPP films without these additives usually have the highest light transmittance.
- Surface Finish: The surface smoothness of the BOPP film also plays a role. A film with a smooth surface allows light to pass through more easily compared to a film with a rough or textured surface. Surface treatments such as corona treatment, which is used to improve the film's printability and adhesion properties, can slightly affect the surface smoothness and thus the light transmittance.
Different Types of BOPP Films and Their Light Transmittance
- Super / Crystal Clear BOPP Film Jumbo Roll: This type of BOPP film is specifically designed to have extremely high light transmittance. It is often used in applications where maximum clarity is required, such as packaging for high - end consumer products. The Super / Crystal Clear BOPP Film Jumbo Roll typically has a light transmittance of 92% - 96%. Its high clarity makes the packaged products look more appealing by allowing consumers to clearly see the contents inside.
- Normal BOPP Film Jumbo Roll: Normal BOPP films are more commonly used in a wide range of general packaging applications. They usually have a light transmittance in the range of 88% - 92%. While not as clear as the super - clear variety, they still offer good visibility and are more cost - effective. You can find our Normal BOPP Film Jumbo Roll suitable for various packaging needs.
Implications of Light Transmittance in Different Applications
- Food Packaging: In food packaging, high light transmittance is often desired as it allows consumers to see the food product clearly, which can enhance its appeal. Moreover, clear packaging can also provide a sense of freshness and quality. However, it's important to balance light transmittance with other factors such as UV protection to prevent food from spoiling due to light exposure.
- Labeling: For labels, light transmittance can affect the readability of printed information. A film with high light transmittance ensures that the colors and text on the label appear vivid and sharp. Additionally, in applications where the label is placed over a product, good light transmittance allows the product's appearance to shine through, creating an integrated look.
- Stationery and Office Products: BOPP film is used in various stationery items such as document protectors. High light transmittance is essential here as it enables users to view the documents clearly without any significant distortion.
Choosing the Right BOPP Film Based on Light Transmittance
When selecting a BOPP film for a specific application, it's important to consider the required light transmittance. If maximum clarity is crucial, the super - clear BOPP film would be the best choice. However, if cost is a major factor and a slightly lower level of clarity is acceptable, the normal BOPP film can be a more practical option.
As a BOPP film supplier, we understand the diverse needs of our customers and can provide professional advice on choosing the most suitable film based on light transmittance and other properties. Whether you are in the food packaging industry, the labeling business, or any other field that uses BOPP film, we are committed to providing high - quality products that meet your specific requirements.
If you are interested in learning more about our BOPP films or would like to discuss your procurement needs, please feel free to reach out. We look forward to the opportunity to work with you and contribute to the success of your projects.
References
- "Plastic Films: Technology and Packaging Applications" by A. L. Brody and K. S. Marsh
- "Handbook of Polymer Science and Technology" edited by H. S. Kaufman and J. Falcetta
