To protect and secure products in retail and shipping environments, three main types of films are used in shrink packaging: polyvinyl chloride, polyolefin and polyethylene. Each of these materials has different functions and properties that make them suitable for specific applications.
Shrink films can be made into flat rolls, bags, overwrap, strapping and tubing. They can add a form of tamper-proof protection to packaged goods. Here is a breakdown of the three main shrink film types and their common uses.
PVC was once the world's most commonly used shrink packaging material due to its light weight, affordability and versatility. Since then, it has given way to polyethylene (PE) and polyolefins (POF) for a variety of reasons, including the health risks posed during manufacturing and incineration, as well as its level of sustainability.
PVC film is durable in its rigid form and can be used in applications such as construction projects and household products. In packaging, PVC is suitable for both rigid structures (such as blister and flip-top packaging) and flexible structures (such as shrink wrap and bagging).
PVC is used in many applications in the building and construction industry as well as in the healthcare, electronics and automotive industries. It is used in a variety of products, from pipes and siding to blood bags and tubing, wire and cable insulation, windshield system components, blister packaging, flip-tops, etc. Applications for PVC shrink film include packaging for CDs and DVDs, boxes for games and software, and other non-edible items.
Polyolefin shrink film is extremely durable and versatile, making it a premium choice. It has replaced PVC in many applications and is an FDA-approved food-safe material. POF materials have different properties. One option is cross-linked film, which provides high tensile strength and incredible clarity for high-speed packaging applications. Cross-linked film also prevents buildup on the sealed parts of your machine.
Because of the added strength of POF, longer, thinner rolls of film can be produced. This reduces roll changes and increases efficiency and productivity. POF shrink film offers excellent puncture resistance and sealing strength, helping to protect irregularly shaped items throughout their supply chain lifecycle.
Common uses for POF shrink film include toys, games, candy, books, food, most retail items, and any consumer product where appearance is important. When we say it's versatile, we're not kidding! Depending on your need for a barrier layer or MVTR, additives can be used in combination to provide you with exactly what you need for this packaging film.
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Polyethylene is a polyolefin, which means it is a single monomer film formed by adding ethylene during the polymerization process. PE is used in many forms of flexible protective packaging, including shrink and stretch films, each of which behaves very differently.
The three most common forms of PE include high density polyethylene, low density polyethylene and linear low density polyethylene.
While POF and PVC are available in limited gauge thicknesses (typically around 100 gauge), higher gauge PE can be as high as . these thicknesses are used in marine industry applications such as shrink wrapping ships for storage. the disadvantages of PE for shrink are low shrinkage (typically around 20%) and significantly reduced clarity.
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- Friday, September 6,
Heat shrinkable film is a common packaging film. In packaging applications, it is often used to heat the shrinkage characteristics to achieve a skin packaging or bundle wrapping. It can also be used to protect content from contamination or damage.
The heat shrink packaging machine utilizes the principle of heat shrinkage of the shrink film. After the raw material is melted, the film is stretched under an external force at a predetermined temperature, and the macromolecules cannot slip each other. When it cools below the crystallization point or glass transition temperature, the molecular orientation is rapidly solidified. When it is reheated to above the melting point or glass transition temperature, the polymer segment will be reactivated, so the originally oriented molecular segment begins to distort and macroscopically appears as film shrinkage.
Heat shrinkable films can be broadly classified into two types, barrier shrink films and non-barrier shrink films.
The barrier shrink film is mostly a 5~9-layer co-extruded structure containing a barrier material (EVOH, PVDC), which is produced by a three-bubble coextrusion film process. It is generally applied to meat or fresh food packaging that has certain requirements for oxygen barrier properties.
Non-barrier shrink films have many classifications. According to different raw materials and processes, they are roughly classified into four types (PVC shrink film, PE shrink film, POF shrink film, and other shrink film).
PVC shrink film
PVC shrink film is one of the oldest shrink films in history. It is produced by a double bubble process using two inflations of PVC. PVC shrink film has the characteristics of high transparency, high stiffness and low shrinkage temperature. The uppermost layer of this surface film is lacquer, the main component in the middle is polyvinyl chloride, and the lowermost layer is a back-coated adhesive. It is a popular and widely used synthetic material in the world today.
PE shrink film
The PE heat shrinkable film is a heat shrinkable film produced by using polyethylene as a raw material. Unlike PVC shrink film, PE shrink film is produced by a common blown film process. Since the processing temperature is high (far exceeding the melting point of polyethylene), low density polyethylene (LDPE) containing a large amount of long-chain branched structure is generally used as a raw material for production. With the development of catalyst technology and polymerization processes, this film provides excellent mechanical properties while providing better lateral shrinkage.
PE film is widely used in the whole collection packaging of wine, cans, mineral water, various beverages, cloth and other products. The product has good flexibility, strong impact resistance, tear resistance.