How does heat shrink plastic?

Because the plastic bottle is compressed

During storage and transport, the protection of your goods is essential. The reason why securing is very important when you choose your film is to avoid any risk of breakage, that’s why your film can be shrink or stretch. What are the advantages of shrink film?

Shrink film is very effective, as it is a film that shrinks with heat and adapts to the shape of the goods it has to protect. It is highly resistant to weathering, temperature changes, inclement weather and UV rays.

Shrink packaging is an affordable and cost-effective option, but finding effective packaging solutions can be a costly process, especially for packages with complex shapes.

Heat shrinkable plastic for cables

Shrink wrapping machines are tools used for packaging at the end of a production line, during the packaging process. They are used to pack or wrap the goods in a thermoplastic film, thus completely protecting the product from external agents such as dirt or tampering.

Shrink wrapping machines make it possible to apply shrink wrap automatically, semi-automatically or manually. The shrink wrapping process is one of the most commonly used product packaging solutions in logistics centers or factories because of the good results it offers.

Manual shrink wrappers; The process is carried out by hand by an operator in all phases and are machines that include sealing machine, reel holder and heat hood. The operator wraps the product in the shrink wrap and places it in the machine in order to close the ends thanks to the sealer and then the hood applies heat on the package.

Semi-automatic shrinkwrappers; They require the participation of an operator, but to a lesser extent than the manual option. The operator is in charge of covering the product with plastic and puts it inside the machine, where the sealing and shrink wrapping takes place. The person only intervenes at the beginning of the process to place the product and remove, at the end, the already wrapped product.

Shrink plastic

Polyvinyl chloride, better known by its acronym, PVC or vinyl, is a thermoplastic polymer made of 57% chlorine, derived from industrial salt, and 43% carbon (derived predominantly from oil and gas), therefore, it is less dependent on crude oil or natural gas than other polymers, in addition, chlorine, being a halogen, gives it excellent fire resistance.

PVC is one of the oldest synthetic materials, with the longest history of industrial production. It is believed to have been discovered accidentally on at least a couple of occasions during the 19th century. The first, in 1838, by the French physicist and chemist Henri Victor Regnault and the second in 1872 by the German Eugen Baumann.

Plastisol is a PVC mixture in which plasticizers predominate and is the material used to make decorative parts such as refrigerator magnets and the plastic finishes of clothing.

Today, most polyethylene film is manufactured in a three-layer co-extrusion with different polymers, the main ones being ethylene vinyl acetate (EVA) for its puncture and tear resistance and polyethylene (PE) modified with a number of additives.

Acetate shrinks

The injection of thermoplastics is a physical and reversible process, in which a raw material called thermoplastic is melted by the effect of heat in a machine called an injector. This machine injects the molten thermoplastic into the hollow cavities of a mold at a certain pressure, speed and temperature. After a certain time, the molten plastic in the mold loses its heat and becomes solid, copying the shapes of the hollow parts of the mold where it has been housed. The result is a solid piece of plastic, but with shapes and dimensions similar to the hollow parts of the mold. This solidified thermoplastic is called injected.

Why do we say that thermoplastic injection is a physical and reversible process? Physical, because there is no variation in the chemical composition of the thermoplastic throughout the process. Reversible, because the thermoplastic after the process has the same characteristics as at the beginning. That is, we could grind the piece and repeat the process with that material. Although in practice, the plastic may degrade and lose some of its properties.