Flexible packaging materials

Flexible packaging uses quite a wide range of materials that include polymer films, paper, metallic foil, cellulosic and bioplastic films.

Many factors influence the selection of the materials (substrates) that best suit the product to be packed such as layer role in the package construction, mechanical strength, barrier, printing, heat resistance, sealing parameters, visual appearance, recyclability, cost etc.

Here are described some main characteristic of the most frequently used materials in flexible packaging production.

Polymer films

Wide variety of polymer films can be converted into many shapes, sizes, with many different performance characteristics. Plastics are very flexible, durable, and cost-effective compared to other materials which is the main reason why they are now dominated the market of FP.

The following polymer films are most commonly used in the manufacture of flexible packaging in our company:

  • BOPE (Biaxially-oriented polyethylene)
  • BOPE films offer high stiffness, excellent tensile strength and puncture resistance, excellent heat-seal strength, high gloss and transparency and good moisture barrier. These films are easy to produce with low cost. We can find BOPE films in applications such as shopping bags, for perishable goods like packages of food items, pharmaceuticals, liquids, spices, pesticides, industry goods, cosmetics, laundry detergents etc.

  • BOPET (Biaxially- oriented polyethylene terephthalate)
  • The BOPET films offer superior stiffness, chemical inertness, good oxygen - barrier properties, high tensile strength and high heat-resistance. They are popular surface films in laminations and are used to protect food against oxidation and aroma loss in products such as coffee packaging and pouches for convenience food.

    White POPET is used as lidding material for dairy products such as yogurt while clear POPET dominate as lidding material for fresh or frozen ready meals.

  • BOPP (Biaxially-oriented polypropylene)
  • BOPP films are easy to produce with low costs. They have good chemical compatibility and offer superior moisture vapor barrier properties. They are often metalized for better barrier performance and as such are suitable for hot filling. BOPP films are used for clear wraps and most snack food, for food pouches and (gusseted) bags, dairy products and confectionery, for personal care and hygiene products, pesticides.

  • BOPA (Biaxially- oriented polyamide)
  • BOPA film is highly transparent and has exceptional toughness and puncture-resistance. It performs good oxygen, chemicals and aroma substances barrier. It is used for packaging of perishable food, for food sensitive to oxygen and for distilled goods packaging, agricultural products packaging or medical products.

(Kraft) paper

Kraft Paper has high tensile strength and elasticity, good tear resistance and is designed for packaging products with high demand for strength and durability. It is used for products like single multiwall paper bags and sacks (for cement, food, chemicals, consumer goods, flour bags etc.), sale bags for bakery products, wrapping.

Aluminum foil and metalized substrates

Aluminum foil has the best dead fold properties. It provides an excellent 100% barrier to all gases, moisture and light. It is a good reflector of radiant heat, usually supported with plastic and/or paper (in multy-layer structure) because it cracks when folded. Alone does not provide an acceptable aroma or odder barrier. It is mainly used for tamper-proof lidding for yogurts, flavored drinks, cosmetics, food stuff, beverages and powders, for confectionery and ready meals, soups and sauces, preserved and liquid foods, pharmaceuticals.

Cellulosic and bioplastic film

They efficiently prevent the permeation of oxygen, grease and oils but have very poor moisture barrier properties (without coating or lamination). These films are easy recyclable, biodegradable and compostable. The use of cellulosic and bioplastic films are growing in the food, bakery, confectionery and snack-packaging industry.

When choosing a design, it is extremely important to determine the right flexible packaging material.

Single and multi-layer materials

Some flexible packaging is made from a single layer material while, in other cases, multi-layer materials are required to provide the appropriate barrier and protection. Each layer performs a different function in protecting and preserving like: product protection, contamination prevention, extended freshness, puncture, burst and tear resistance, seal and tensile strength.

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Barrier properties

The materials used for flexible packaging may require protection of the product inside the packs, such as moisture, oils or greases, chemicals, detergents, etc. or to protect the product from external influences, such as atmospheric impurities, light, UV rays, gas, oxygen, moisture, puncturing are tearing. It is important that the elements are not able to migrate into or out of the package.

Prepustnost materiala - barierne lastnosti