What is Industrial Heat Sealing and How Are Heat Seals Used?
Industrial heat sealing joins two pieces of heat-sealable material with a bond that can hold out air and water. People also call it heat welding. The process uses heat and pressure to connect compatible fabrics, films, or coated materials into one sealed seam.
For Vinyl Technology, a heat seal often involves PVC, vinyl fabric, or other thermoplastic materials. These materials react well to controlled heat, which makes them useful for products that need strong seams with a clean barrier. Think protective covers, containment products, inflatable items, medical components, & industrial fabric parts that need more than a stitched seam can provide.
A sewn seam has thread and needle holes. A heat seal bonds the material surface directly, which gives the finished product a tighter seal. That is the main reason heat sealing shows up in work where leaks, moisture, or outside contamination can cause problems. Pretty practical stuff, even if the machine doing it looks a little intense the first time you see one run.
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How Is Heat Sealing Used in Thermoplastic Materials?
Heat sealing works because thermoplastic materials soften at high temperatures. Once the surface reaches the right point, the material can bond with another compatible surface under pressure. As the seam cools, the joined area becomes one connected piece.
The temperature has to match the material. The pressure has to fit the thickness. The timing also has to be right. A thin vinyl film needs a different setup than a heavier coated fabric. That is where experience matters in industrial heat sealing: the bond depends on the material, the equipment, and the end use of the product.
A good heat seal should look clean and hold steady under real conditions. It may need to resist water, air, chemicals, pressure, handling, or repeated use. Vinyl Technology uses heat sealing for various custom-manufactured products.
Common Household Uses of Heat-Sealable Devices
Most of us know heat sealing from late-night TV commercials for devices that can seal familiar household items like potato chip bags. Industrial heat sealing is perfect for this because most plastic bags used in the kitchen are thermoplastic and react extremely well to the high temperatures required. Heat seals are also good for this type of use because the bond they create, at the molecular level, is waterproof and airtight–exactly what you need for food safety and preservation.
How Is Industrial Heat Sealing Used?
If you guessed that heat sealing would be useful in other areas, you’d be right. The advantages of heat seals, like fire-retardant properties, oil and chemical resistance, and high durability and strength, make it the ideal solution for many industrial-strength applications. You can read about some of them on the Vinyl Technology website, like the DPE (Demilitarization Protective Ensemble), G-suits, and most medical-grade PPE.
Two kinds of heat-sealed welding apply to both the kind you’d use at home and those used by companies like Vinyl Technology: impulse and constant heat.
Impulse Thermal Sealing
Impulse sealing refers to the on-demand nature of this particular bonding process–this method is mostly used in those household applications you likely already know. The machines that produce these seals only heat up for the exact amount of time it takes to make the bond and then rapidly cool. This method uses less power than other methods and is best used for thinner fabrics that also tend to have a lower melting point.
Constant or Direct Thermal Sealing
Constant, or direct heat sealing, is just what it sounds like. It typically uses two opposing elements, like metal bars, that are constantly supplied with power. This means that they’re also constantly hot, in order to maintain the higher average temperature required to make the required bonds. This method is the preferred heat seal for thick fabrics like Mylar, because of the high heat it uses.
When is RF Welding Involved?
Although not technically a variety of heat sealing like the kind created by impulse or constant industrial heat sealing machines, RF Sealing, or dielectric sealing, is usually included in the menu of services provided by companies like VTI. This process uses RF waves to excite the molecules of the materials to be joined from the inside out, fusing the materials together.
When used by Vinyl Technology, RF energy is directed through electrodes (dies) custom-designed to the required shape of the seal or bond. This makes RF sealing the most versatile of the polymer film sealing methods.
Vinyl Technology also utilizes RF welding and industrial heat sealing to create other products, such as chair cushions, water storage bags, and self-inflating field mattresses.
Which version of a heatseal is right for your project, and what kind of thermal seal do you need? You can get the answers to these questions and more when you get in touch with us.
Article Reviewed For Accuracy By: Jackie Sanchez, VP of Sales Operations
Jackie Sanchez is the VP of Sales Operations at Vinyl Technology.
Jackie became a VP in 2021 following over four years of service as our Director of Human Resources. Her leadership competencies include human resources capacity, ethical conduct, strategic thinking, decision making, and financial management.
She holds an undergraduate degree from Chapman University. Follow her on LinkedIn.