The Ultimate Buyer's Guide for Purchasing pearlised bopp film characteristics

What Is BOPP Plastic Film? BOPP Film Manufacturing Process

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BOPP plastic film, or Biaxially Oriented Polypropylene film, is a versatile and widely used material in various industries. From food packaging to product labeling, BOPP film is known for its strength, transparency, and durability. In this article, we will examine the concept of BOPP film, its characteristics, and the manufacturing process.

I. What is BOPP film?

Definition

BOPP (Biaxially-Oriented Polypropylene) film is a plastic film with a wide range of applications in packaging, labeling, and laminating industries. It is produced by extruding polypropylene resin into a thin film and then stretching it in two perpendicular directions, known as biaxial orientation. This process enhances the film's strength and durability, making it resistant to tearing, puncturing, and other forms of damage.

BOPP Films are the substrate of choice for food packaging worldwide due to their inherent moisture barrier properties, sealability, high clarity, graphic reproduction, and shelf appeal. They provide the best possibility of the pack having a monolayer or homogeneous structure.

It is often used as a co-extruded heat-sealable reverse-printed film for food packaging. In labeling, it is favored due to its benefits in terms of yield (the lowest density of 0.55 for the IML orange peel effect) and recyclability with PP containers and other materials. The high demand for BOPP Films worldwide is mostly due to the growth of the flexible packaging sector.

Benefits of using BOPP film

BOPP film became a common type of plastic film used in a wide range of packaging, labeling, and laminating applications due to its numerous benefits. Some key advantages are:

• Shelf life extension

BOPP film offers the best moisture barrier among regularly used plastic films, and its metalized version provides the best oxygen barrier. These characteristics are crucial for food packaging as they increase product shelf life and decrease food waste.

• High clarity

BOPP film's excellent transparency makes it ideal for packaging applications where product visibility is important. This clarity allows customers to see the product clearly, helping to increase sales and improve the packaging's overall aesthetic appeal.

• Product quality

Due to its limited gauge spread, BOPP film offers consistent and exceptional seal integrity alongside its barrier capabilities. The food packaging industry benefits from strong heat seal strength, reduced seal initiation temperature, a wide sealing window, and superior machinability.

• Aesthetic/Graphics

Clear BOPP films' excellent transparency allows for high degrees of visual appeal in product packaging. In this film, half-tone printing tasks with multicolor printing may be easily completed for high-quality graphics. Excellent gloss, great opacity, and exceptional whiteness in the white opaque film type provide an attractive appearance.

The superb metallic look of the metalized film variant makes products stand out on the shelf. Post-lamination procedures like foil stamping, UV spot coating, and embossing enhance the visual appeal of product packaging, thanks to the material's high surface tension.

• Versatility

BOPP film can be easily converted into bags, pouches, laminates, and other packaging forms, making it cost-effective and efficient for many packaging needs. Its versatility allows manufacturers to tailor the packaging to their product's specific needs, whether for presentation, protection, or both.

• Density

BOPP films have a special quality compared to other regularly used flexible packaging films. Low density promotes the idea of using less plastic per product by increasing yield during conversion. Low density leads to lighter rolls that are easier to handle since they weigh less per roll than other plastic films of the same length.

• Sustainability

In comparison to other plastic film substrates like polyester, BOPP film has a relatively low carbon footprint. Due to its eco-friendliness in flexible food packaging, BOPP Film is the second most favored substrate after cellulose film. Low melting point materials need less energy to change from one form to another. Reprocessed BOPP resin granules are often used to create injection-molded components, furniture such as chairs and tables, and other home products like seat mats.

• Cost-effectiveness

BOPP film is an economical choice for packaging and labeling, as it is readily available, easy to convert, and has a low cost per square foot compared to other materials. This cost-effectiveness makes it an attractive option for companies looking to reduce costs while still providing quality packaging.

II. What is BOPP film used for?

BOPP film is a versatile material with a wide range of applications across many industries. Some key applications of BOPP film include:

Food & Beverage Packaging

BOPP film is widely used in food and beverage packaging due to its high strength and durability, as well as its moisture resistance. BOPP film can create various types of packaging, including stand-up pouches, vacuum pouches, and side gusseted bags. These types of packaging help protect food and beverage products from damage during transportation and storage.

Labeling and Branding

BOPP film's high transparency and clarity make it effective for labeling. Its smooth surface is easy to print on, allowing for eye-catching and informative labels that help build brand recognition and customer loyalty.

Laminating

BOPP film can laminate various materials, including paper, cardboard, aluminum foil, and print materials. BOPP film enhances the strength and durability of the materials it is laminated to, making it suitable for brochures, posters, and other print materials.

Tamper Evident Films

BOPP film is used in producing tamper-evident films, securing products and preventing unauthorized access. These films are often used in packaging products that need protection from tampering, such as pharmaceuticals, electronic components, and similar items. This ensures that the products remain secure and protected, while also providing consumer protection and confidence.

Personal Care Product Packaging

BOPP film is used in personal care product packaging, such as cosmetics, shampoos, and similar items. Its high strength, durability, and moisture resistance make it ideal for packaging products that need protection from damage and maintaining their quality. BOPP film can also create attractive packaging that helps build brand recognition and customer loyalty.

Medical Packaging

BOPP film is used in medical product and device packaging due to its strength, durability, and transparency. BOPP film can create various medical packaging, including bags, pouches, and blister packs. These types of packaging help protect medical products and devices from damage while allowing for easy content identification.

Adhesive Tape

BOPP film is often used to make various types of adhesive tape, including packaging tape and Scotch tape. Its strength and resistance to tearing make it ideal for applications requiring a strong and reliable tape.

Agricultural Films

BOPP film is used in producing agricultural films, such as greenhouse covers and mulch films. Its high transparency allows light to penetrate, while its resistance to weathering helps protect crops from the elements.

III. How is BOPP film made?

In the flexible packaging sector, BOPP (Biaxially-Oriented Polypropylene) film has been utilized for many years. It is well regarded for its affordable price, superior optical and mechanical features, and exceptional gas barrier qualities, particularly water vapor. Below is a detailed demonstration of the BOPP film manufacturing process:

Step 1. Raw material feeding system

Isotactic Polypropylene, a semi-crystalline thermoplastic polymer, serves as the primary raw material in the center layer. While ethylene-propylene copolymers and/or ethylene-butane-propylene copolymers are used for the outer layers. A hopper system introduces these ingredients into the extruders.

Step 2. Extrusion

The materials are melted and heated to 200–230°C within the extruders before being fed into the extrusion head, where they emerge as a foil.

Step 3. The foil cooling

The foil is then brought into direct contact with a chilled cylinder before being submerged in a water bath to cool the melt.

Step 4. Machine direction orientation (MDO)

The film is subsequently passed over many rollers, which raise the temperature and prepare the film for longitudinal stretching (machine direction). By moving the foil between the rollers that spin at increasing rates, stretching is accomplished. The polymer chains are aligned at this point after the foil has typically been stretched up to five times its original length. The mechanical qualities of the film may be improved at this step, and the thickness can be cut by up to five times.

The film is heated again after stretching to remove the tension created (annealing phase).

Step 5. Transverse direction orientation (TDO)

A quick-moving chain of metal jaws grabs the film on both edges once it exits the longitudinal stretching zone (tenter clips). The film is stretched transversely by the diverging rails after being heated up in an oven in the middle (i.e., stretching in the transverse direction up to 9 times its original width).

The macromolecules align at this point, but this time in a transverse orientation, improving the mechanical characteristics of the film and reducing its thickness by up to 9 times. After stretching, the chain and the film converge, allowing it to balance off the tension that built up during stretching (annealing phase).

Step 6. Thickness measurement and flame treatment

The film enters a new processing step where the thickness is automatically measured (along the entire width). After that, one of the faces is given a flame or corona treatment to prepare for the subsequent conversion processes, specifically to change the surface that will serve as an anchor for materials like ink (for printing), glue (for laminating), or metal (metallization process).

Step 7. Reel winding

After being wound around a reel, the film is sliced to the specific measurements.

Step 8. Film measurements

The following are the primary metrics that the final product is subject to:

• Density, grammage, and thickness
• Elastic modulus, elongation at break, and tensile strength
• Haze (opacity) and Gloss (sparkling appearance)
• The friction coefficient between films and between films and metals
• Sealing strength and threshold °C
• Temperature stability (heat shrinkage)

The film has at least three layers and a thickness between 15 and 60 microns; the center layer is the thickest and primarily responsible for the mechanical qualities, while the two outer layers provide the film with different characteristics (i.e., heat-sealing properties).

To fully fulfill the application criteria, additives may be added depending on the ultimate application the film is intended for.

IV. BOPP film raw material

BOPP (Biaxially-Oriented Polypropylene) film is produced from PP (Polypropylene) plastic resins. This type of plastic is harder than PE and is considered to have the general characteristics of good tensile strength and higher transparency than other kinds of plastic. Besides, BOPP film is also known as a thin film, with a thickness of 10 ~ 40 microns. It is due to the low density of PP particles, only 0.90 g/m³.

Currently, EuroPlas is proud to be the world's No. 1 filler masterbatch manufacturer, bringing customers unique plastic raw material solutions to optimize production costs and improve competitiveness. EuroPlas's PP filler masterbatch is a combination of CaCO3 stone powder, PP base resin, and appropriate additives.

EuroPlas's PP filler masterbatch for BOPP plastic film manufacturing is committed to helping customers:

• Optimize production costs
• Improve some surface features of finished products: increasing hardness, reducing shrinkage
• Save fuel thanks to the good thermal conductivity of CaCO3
• Reduce mold cooling time and shorten the production cycle

If you are looking for a high-quality PP filler masterbatch for BOPP plastic film manufacturing, do not hesitate to contact us for the earliest advice and support.

BOPP film is the most in-demand packaging material due to its flexibility and durability. Its strength, versatility, and outstanding mechanical properties make it the best among others. Moreover, what if the packaging material is also cost-effective and eco-friendly?

These added perks make you inclined toward buying specific packaging material. Amazingly, global BOPP film manufacturers facilitate you with these benefits.

Let’s look at the reasons for the popularity of polypropylene films!

Reasons

1. Amazing properties and benefits
2. Wide variety of BOPP film rolls
3. Compatible with countless industries
4. Decorative purposes
5. Printability
6. Edge over paper packaging
7. Distinctive polypropylene-based film
8. Environmentally Friendly

BOPP Films Properties & Advantages

• They are flexible, allowing them to wrap on various products.
• They are water, heat, and chemical resistant.
• Food-grade polypropylene films are safe for health.
• They are recyclable and eco-friendly.
• BOPP plastic films are lightweight and easy to wrap.
• These films increase the shelf life of edibles.
• BOPP films are cost-effective, strong, versatile, and durable.

BOPP film rolls possess the following astonishing characteristics:

• Heat sealable
• Ideal surface gloss
• Moisture-resistant
• Anti-static
• Low toxicity
• Anti-fogging
• Printable
• Extended shelf life
• Solvent & acid-resistant
• Durable

Due to the increasing controversies against the use of plastic, plastic has become taboo. Authorities have banned single-use plastic. To overcome this problem, global BOPP film manufacturers use polypropylene as their raw material. Polypropylene emits the lowest carbon dioxide compared to other plastics.

The BOPP film manufacturing process is also safe for the environment. This process uses less energy. As the emphasis on energy conservation increases, BOPP is taking over conventional (plastic) packaging.

Moreover, BOPP is among the recyclable materials. Therefore, the BOPP film manufacturing process takes place without toxic emissions, halogens, or toxic wastes, causing no hazardous effect on the environment.

The Manufacturing Process of BOPP Film

BOPP is a multi-layer film having polypropylene at its core with several additional layers. When polypropylene is oriented in two directions, it guarantees that the resulting BOPP film has excellent mechanical properties and durability in both these directions.

Layers of BOPP film may also contain a combination of appropriate functional additives and polymers that determine its barrier properties, whiteness, opacity, gloss, or matting. So, the manufacturer is in complete control of film properties.

A BOPP film can be produced by several methods but three processes are most commonly used. These include the Tubular process and Tenter Frame Sequential process.

1) Tubular Process

In this process, BOPP film manufacturers create the sheet by extruding a thick plastic tube. After that, the tube passes through the stretching heaters and inflates into a tubular bubble.

Then the bubble is compressed, and the lay-flat stretches and gives the sheet its required thickness. Nevertheless, this process is not as commonly used as the tenter frame process.

2) Tenter Frame Process

In this BOPP film manufacturing process, a thick plastic sheet is softened at a low temperature. Then it is stretched 300 – 400% in two directions.

There are two methods for biaxial orientation – simultaneous or sequential. In the tubular process and some new-technology tenter frame processes, simultaneous orientation forms BOPP sheets. Contact us to discuss your requirements of what is bopp packaging material. Our experienced sales team can help you identify the options that best suit your needs.

However, most commonly, BOPP film manufacturers use sequential orientation to form polypropylene films.

Polypropylene Film Types

BOPP is available in many types, namely:

• Clear BOPP Plastic Film

These transparent films are most commonly used for food packaging, for example, pulses, nuts, fresh fruits, vegetables & meat, cookies, etc.

• Pearlized BOPP Film

Ideal for printing and is a perfect inner sealant for products like chocolate, ice cream, and labels for soda drinks.

• BOPP Thermal Lamination Film

It is an ideal solution for two-sided printing. These films are usually used for brochures, shopping bags, textbooks, leaflets, etc.

• Matte Polypropylene Film

This film is suitable for printing