Who, upon traveling, would leave their house doors open or unlocked? No one. You would lock your doors to ensure that your personal belongings are kept intact and well secured. This also applies to packaging.
Proper packaging not only keeps your product safe from manipulation during delivery but also leaves quite an impression on your customers and gives credibility to your business.
A properly sealed package would have a longer shelf span and preserve the integrity of the contents inside the package. However, this would be impossible if you did not seal the package adequately. The proper heat-sealing technique is the foundation every heat-sealed pouch is built on.
What is heat sealing?
Heat sealing combines two plastics by applying high temperature and pressure to the areas in contact to form an airtight, leak-proof sealed bag.
Heat sealing is used for joining thermoplastic fabrics. This process completely seals off the interior of the thermoplastics, thereby making the components inside the sealed package sterile. Thermoplastic is usually the best material for heat sealing because its thermoplastic fabric melts into liquid when applied at high temperatures.
When two thermoplastic fabrics are melted together at the same time by an increased temperature, the molecules of both fabrics intertwine and join together on cooling to form an airtight, sealed bag.
Heat sealing is used across several fields. It is used in the medical field to seal medical fluid bags, blood bags, bottles, and containers to prevent contamination that could alter the results of medical tests.
It is used in the telecommunication industry to join LCDs to PCBs in many electronics; it is used in the food processing industries to seal the packets of food products, including perishables, for example, sandwiches, bread, and others, efficiently to ensure the hygiene and freshness of the products, its application could also be seen in typical household uses: it is perfect for preservation at home because most plastic bags used in the kitchen are thermoplastic and react extremely well to the high temperatures required.
And when they are heat sealed, the bond they create, at the molecular level, is water-proof and airtight–precisely what you need for food safety and preservation. Moreover, heat sealing is widely used in the packaging industry for sealing bags, films, and containers made from thermoplastics.
What are heat-sealed pouches or bags?
A heat-sealed pouch or bag is a type of thin, flexible container made up of thermoplastic materials that are sealed/closed through high temperature and pressure.
It contains and transports goods such as foods, chemicals, specific products, etc. It is a common yet efficient form of packaging because it keeps your product fresh and clean for a more extended period, which is the main aim of packaging in the first place.
Benefits of heat seal packaging
There are several benefits of heat seal packaging, which include:
Safety
Heat seal packaging ensures that the package can withstand humidity changes and rough handling without easily getting damaged. The seal also leaves a mark once it is tampered with, so any damage or manipulation to the packaging is immediately detected. This guarantees its safety and gives you this peace of mind that your product is safe and has not been contaminated or altered.
Freshness
Heat seal packaging protects your products. It guarantees that the package remains airtight, thereby protecting it from external damaging factors, preventing contamination by microorganisms, and preserving the quality and freshness of the product for a longer period.
Appealing look
Packaging/branding goes a long way in selling a particular product. Heat seal packaging makes the product have a cleaner and more attractive look; it does not consume a lot of display space, leaving more room for important details and images on the packaging to attract the customer.
Low costs
Heat seal packaging is suitable for mass production and may require low energy consumption.
Durability
Heat seal ensures that the packaging can withstand rough handling. Also, heat seal packaging provides an airtight environment, protecting the package from external forces causing damage, preventing most forms of contamination, and extending its shelf life.
Recyclability
Heat seals have a strong bonding force and can easily be recycled. The major importance of recycling is that it greatly benefits the environment by preventing waste.
Temperature resistance
Heat seal packaging can withstand low temperatures of -40°F (-40°C). Depending on the product, it may also stay up to two years in storage with no particular requirements, making it last longer. Perishables would require refrigeration.
Fast and Easy to do
Heat sealing is relatively easy to do. Place the ends of the sealing bag under the sealing bar and press it down for a few seconds. The sealing bar gets heated up almost instantly; hence not much time is wasted
Anti-theft performance
The heat seal leaves a mark once it is tampered with. Because of this, any damage or manipulation to the packaging is immediately detected. Heat seals provide increased anti-theft and anti-tampering properties due to their strong bonds. Any attempt to open the product will leave a mark on the package, as stated earlier. Tamper-evident packaging is now a growing trend with the rise of e-commerce, and heat seals help address the needs of manufacturers.
How does heat-sealing work?
The heat-sealing device works by generating a high current. This leads to an increase in temperature, which is enough to melt, then join the thermoplastic fabric or other materials with a thermoplastic layer pressed between the sealing bars, hence sealing it up. In simple terms, it works by using pressure and hot temperature to join two thermoplastic materials, make them stick together, and then seal them. Heat sealing is used for many applications, including heat seal connectors, the food industry, film media, etc.
It is important to note that heat sealing joins together similar materials and different materials as long as they have a thermoplastic layer. Once the sealing bar is heated to enough degrees, the material is melted and joins together like a zip liner bag.
How to heat seal a bag (Video)
To heat seal, you will need suitable materials, which include a heat-sealing machine, and the bag (made up of thermoplastic materials) to be heat sealed.
The procedures for heat sealing are as follows:
- First, a test strip should be heat-sealed. The test strip should be constructed with the same materials as the bag to be heat-sealed. This is done to ensure that a good heat seal is made.
- Set the machine’s temperature to a lower set point of 700°F, the recommended temperature for most heat sealing, and adjust higher to 727°F, if needed.
- Fill the bag with desired contents (avoid getting any product into the zipper area and do not overfill the bag).
- Gently run your fingers across the zipper to close the bag securely.
- Place the top of the filled bag between the seal bars, just above the tear notches.
- Press down gently for approximately 2-3 seconds and release.
- The heat sealer melts the material until it joins together, then sets it into a single, neat layer of plastic. As it cools, the thermal material will contract, tightening the seal.
FAQs
What is a heat-sealed polybag?
From this article, a heat-sealed bag is a type of flexible bag made up of thermoplastic materials. It is sealed/closed using pressure and an increased temperature.
This bag is used majorly by production companies but can be used by anyone to contain and protect their goods from manipulation and contamination during delivery. It also preserves the quality and freshness of products for a more extended period.
As said earlier, the heat-sealed bag is a common yet efficient form of packaging because it keeps your product fresh and clean for a longer period, which is the main aim of packaging in the first place.
What type of bags can you heat seal?
Almost any type of poly bag made up of thermoplastic materials can be heat-sealed, including polythene, polyethylene, and polypropylene.
Low-density polyethylene, in particular, is ideal for making heat seal poly bags. This lightweight material melts at 320 degrees Fahrenheit, which means it can be heated, fused, and cooled quickly after removing the heating element. Common examples of these plastic bags are:
- Cling wrap and sandwich bags
- Grocery bags and frozen food bags
- Flexible container lids
- Dry cleaning bags
- Newspapers wrapping
- Grocery bags/ shopping bags
- Cereal box liners
- Bread bags
- Garbage bags
- Plastic mailing envelopes
- Commercial packaging
- Freezer bags
What temperature should I heat seal?
The sealing process, as described earlier, requires a temperature high enough to melt the plastic to make them join together to form a neat single layer of the seal. So, the recommended temperature for heat sealing is 700-727°F.
Conclusion
In summary, heat sealing is of great importance in the production industry; it offers several advantages and benefits, including safeguarding products from damage during delivery and protection against manipulation by intruders. It also prevents microorganisms from entering the sealed package, increasing the product’s shelf life and protecting it from early decay and spoilage.
Interestingly, no one would want to purchase an unsealed product, especially if it is a food item. So, heat-sealed products assure your customers of your products and give credibility to your business.
About Us – AtlasPackagingInc
Atlas Packaging & Displays was founded with the vision of manufacturing innovative, value-added packaging materials and products from recycled and renewable materials. We help small businesses, eCommerce companies and franchises design packaging designs that suit every company.
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