Hey there! As a supplier of OPP plastic bags, I often get asked about the different types of seals available for these bags. OPP, or oriented polypropylene, is a popular choice for making plastic bags due to its clarity, strength, and moisture resistance. In this blog post, I'll walk you through the various seal types that you can choose from for your OPP plastic bags.
Heat Sealing
Heat sealing is one of the most common methods used to seal OPP plastic bags. It involves applying heat to the edges of the bag to melt the plastic and then pressing the melted edges together to form a bond. There are a few different types of heat sealing techniques:
Side Seal
Side seal bags are sealed along the two vertical sides and the bottom. The top remains open for easy access to the contents. These bags are great for packaging items like snacks, small toys, or stationery. You can customize the size and shape of side seal bags according to your needs. For example, if you're selling small candies, you might opt for a narrow and tall side seal bag. Check out our Large Roll Of Plastic Wrap for more options.
Bottom Seal
Bottom seal bags, as the name suggests, are sealed only at the bottom. The two sides and the top are left open initially. This type of seal is commonly used for items that need to be filled from the top, such as powders, grains, or bulk items. Once the bag is filled, the top can be heat sealed as well. Bottom seal bags provide a large opening for easy filling and can be a cost - effective option for packaging larger quantities of products.
Center Seal
Center seal bags are formed by folding a sheet of OPP plastic in half and then sealing the two open edges. This creates a tube - like structure with a sealed center seam. Center seal bags are often used for packaging items like bread, pastries, or other food products. They offer a good balance between strength and visibility, as the contents can be easily seen through the clear plastic. Our Transparent Plastic Bag for Food is a great example of a center seal bag suitable for food items.
Zip Lock Seals
Zip lock seals are another popular option for OPP plastic bags. These seals consist of a plastic zipper that runs along the top of the bag. They provide a reusable and easy - to - open and close option. Zip lock bags are ideal for storing items that need to be accessed multiple times, such as leftovers, small parts, or craft supplies.
One of the advantages of zip lock seals is that they offer a high level of convenience. Customers can simply zip and unzip the bag without the need for additional tools. Also, they help to keep the contents fresh by providing a tight seal. We offer a range of OPP plastic bags with zip lock seals, including our OPP Food Grade Vegetable Plastic Bag, which is perfect for storing fresh vegetables.
Adhesive Seals
Adhesive seals involve applying a layer of adhesive to the edges of the bag. When the bag is closed, the adhesive sticks the edges together, creating a seal. Adhesive seals can be either permanent or re - closable.
Permanent adhesive seals are used when you want to ensure that the bag remains closed once it's sealed. This is common in applications where product tampering needs to be prevented, such as in the pharmaceutical or electronics industries.
Re - closable adhesive seals, on the other hand, allow the bag to be opened and closed multiple times. They work similarly to sticky notes, where the adhesive retains its stickiness even after repeated use. Adhesive seals can be a good option for items that need to be protected from dust and moisture, but also need to be accessed regularly.
Ultrasonic Sealing
Ultrasonic sealing uses high - frequency ultrasonic vibrations to create a seal between the plastic layers. This method is fast and efficient, and it produces a strong and reliable seal. Ultrasonic sealing is often used in high - volume production environments, as it can seal bags quickly without the need for additional heat or adhesives.
The ultrasonic waves cause the plastic molecules to vibrate and generate heat at the sealing area. This heat melts the plastic, and when the pressure is applied, the two layers bond together. Ultrasonic sealing is suitable for a wide range of OPP plastic bag applications, including food packaging, medical supplies, and industrial products.
Choosing the Right Seal for Your Needs
When deciding which type of seal to use for your OPP plastic bags, there are a few factors to consider:
Product Type
The nature of the product you're packaging is a crucial factor. For example, if you're packaging food items, you might want to choose a seal that provides a good barrier against moisture and oxygen to keep the food fresh. Zip lock seals or heat seals are often a good choice for food products. On the other hand, if you're packaging small parts or electronics, a permanent adhesive seal or ultrasonic seal might be more appropriate to prevent tampering.
Storage and Handling
Think about how the bags will be stored and handled. If the bags will be stacked or transported, a strong seal like a heat seal or ultrasonic seal can prevent the bags from opening during transit. If the product needs to be accessed frequently, a zip lock or re - closable adhesive seal would be more convenient.
Cost
Cost is always a consideration. Heat sealing is generally one of the most cost - effective methods, especially for high - volume production. Zip lock seals and adhesive seals might be more expensive, but they offer additional features like reusability.
Why Choose Our OPP Plastic Bags?
As a supplier of OPP plastic bags, we take pride in offering high - quality products with a variety of seal options. Our bags are made from top - grade OPP plastic, which provides excellent clarity, strength, and durability. We can customize the size, shape, and seal type of the bags according to your specific requirements.
Whether you need side seal bags for snacks, zip lock bags for food storage, or center seal bags for pastries, we've got you covered. Our experienced team can help you choose the right seal for your product and ensure that you get the best value for your money.
If you're interested in purchasing OPP plastic bags or have any questions about the seal types, feel free to reach out to us. We're here to assist you with your packaging needs and look forward to starting a great business relationship with you.
References
- "Plastic Packaging Technology" by John Crawford
- "Food Packaging: Principles and Practice" by Carol H. Hall
