When selecting plastic film for food packaging bags, there are a few key factors to consider to ensure the material will protect the food effectively. The right plastic balances properties like barrier effectiveness, strength, and safety. Here are some of the most common plastics used for food packaging bags and what makes them appropriate choices:

Polyethylene (PE) – Both low density PE and high density PE offer strength, flexibility, and low cost. Different densities provide the desired toughness and perm ratings for different foods. PE bags can be thin and lightweight. It is resistant to oils and moisture. PE is one of the most widely used food bag plastics.

Polypropylene (PP) – With high tensile strength, PP can be made into durable, reusable bags. It also offers resistance to grease and chemicals. Biaxially oriented PP gives added strength and clarity in thinner films. PP is suitable for snacks, frozen foods, and produce.

Polyester (PET) – PET is clear, tough, and has good gas barrier properties. When oriented, it is used for rigid containers like bottles. In laminates, PET provides puncture resistance. It is often used for foods that need more containment like cereals, nuts, and baked goods.

Nylon – Nylon is added to plastic laminates to provide extra tear resistance, puncture protection, and durability during shipping and handling. It also adds an appealing glossy look. Nylon-reinforced bags are effective for heavy or sharp foods.

When selecting bag plastic, additionally consider factors like FDA compliance, manufacturing methods, recycling codes, and suitable printing/sealing processes. The ideal food packaging bag plastic prolongs freshness and quality while also meeting safety regulations.