Flexographic Printing & Packaging

About Flexible Printing & Packaging

Flexible packaging has no established form of its own but conforms to the product(s) it protects, generally taking the shape of bags, pouches, labels, liners, and wraps. The function of a package is to protect, contain, preserve, carry, dispense, communicate about, and display a product. Advanced flexographic printing methods allow brand owners to effectively market their product and communicate information about it, such as where it comes from, important nutritional information, and even vital tracking information in the event of a product recall.

Without question, flexible packaging is the fastest-growing area of packaging, providing an array of benefits over other packaging forms, including the following;

Benefits

  • Protects the product being packaged, particularly food.
  • Food safety is at the top of the list for all food processors, and flexible packaging ensures that food is packaged and delivered safely across all distribution lines, into retail, and eventually to the consumer.
  • Flexible packaging extends the shelf life of many products, which not only allows consumers more time to savor the taste of their favorite products, but also eliminates unnecessary food waste, which makes up a staggering 1/10 of all global greenhouse gas emissions.
  • With the lowest tare weight ratio of any packaging form, bags and their flexible cousins also have the lowest unit cost, which keeps shipping costs to a minimum.
  • Significant source reduction (reduced amount of material) for packagers, which minimizes weight, cost and storage, and transport size.
  • Flexible packaging is responsible for eliminating unnecessary food waste.
  • Many forms of flexible packaging can be recycled and repurposed, including those made from compostable and even biodegradable materials.
  • Flexible packaging occupies the least amount of space in disposal bins and landfills.
  • Flexible packaging is convenient, and in some cases, re-usable.
  • Flexible packaging offers many substrate options to accommodate various processing conditions including extreme temperatures or distribution and line speeds.
  • Customizable to provide only the needed functional properties for each product being packaged
  • Flexible packaging provides a large canvas for brand owners to showcase their products through brilliant flexographic printing technologies.

Different Forms of Flexible Packaging

Many different forms of flexible packaging are available in today’s market, largely because different product applications require different types of packaging. The production environment, processing conditions, line speeds, shelf life, distribution methods, and other factors will ultimately determine the optimum substrate and packaging form for a given product. In addition, brand connections and marketing also play a vital role in material and packaging form selections. Accounting for all of these factors can be a complicated process, and with the many options available in packaging and film substrates, it is best to consult with an expert for help navigating this process.

A multitude of modern machines exist to handle flexible packaging materials, simply because one machine does not fit all applications. These machines fall into several general classifications, with a variety of machine types and designs available within these broad categories:

  • Vertical Form-Fill Seal (VFFS)
  • Horizontal Form-Fill Seal (HFFS)
  • Horizontal/Vertical Form-fill-seal
  • Controlled Atmosphere and Vacuum Packaging
  • Preformed bag fillers
  • Flow Wrappers & Over Wrappers
  • Auto-Baggers
  • Roll-Fed

The choice of machine will depend on the product and its form and the materials of the package; in other words, choosing the ideal machine will be easier once materials are selected. Material selection could arguably be the most technical and difficult part of the packaging process. With so many factors to consider, it is typically best to start with knowing what product is being packaged, that product’s shelf life requirements, and finally, what processing and distribution conditions exist in the production facility.

Generally, material substrates fall into two categories: (1) single layer, sometimes known as mono web or unsupported, or (2) laminated, sometimes knows as multi-layer, multi-wall, or supported.

Single-layer substrates tend be limited in their application and performance. Although the most economical and suitable for some applications, there is a vast array of applications where a single layer simply will not work. Laminates are made for just this reason: there is no “super-substrate” that will possess all of the desired and necessary characteristics needed for an application. The purpose of a laminate is to combine all of the best properties of multiple substrates, including protection, barrier, aesthetics, cost, and machineability, into a single packing structure.

There are many substrates to choose from, each with its own property characteristics; the following list describes some of the most widely used substrates for food packaging and other markets.

Polypropylene (PP, BOPP, OPP or CPP)

PP films can be made by either blow or cast-extrusion methods. As a plain, unoriented, uncoated film, PP possesses superior optical properties, excellent moisture barrier properties, good dimensional stability, and good heat seal strength, although in a narrow temperature range. It also has low tensile and impact strength, high gas permeability and poor low temperature durability; it has only fair chemical resistance, machine performance and abrasion resistance.

PP film comes in a variety of forms and classifications and can be enhanced with different coatings such as PVDC, Acrylic, EVOH, low temperature seal coatings, white, or cavitated, and is even produced in metallized versions.

Polyester (Polyethylene Terephthalate) or PET

PET films are manufactured by cast extrusion and are usually biaxially oriented. PET films have high tensile strength, low elongations, high melting point, excellent grease/oil barrier properties, low gas and moisture permeability, good printing characteristics, a high-use temperature range, high impact strength, high scuff resistance and excellent dimensional stability.

Polyamide (PA, OPA, or Nylon)

Polyamide or Nylon (former DuPont trade name) can come in Biax or Cast version. Cast versions are less common and used mostly in forming applications. Unoriented Nylon (sometimes known as Nylon 6) is widely used in meat and cheese vacuum packaging because of its good oxygen barrier, grease resistance, and ability to be easily drawn into a thermoformed shape. Oriented nylons are most commonly combined with PE in a laminated structure to form the outer layer of a package. Both types of nylons have excellent optical properties, resist grease, oil, and many chemicals, and are physically very durable, resisting impact, puncture, and cracking when repeatedly flexed. Nylon is not heat-sealable and naturally provides a good barrier to aromatics, oxygen, nitrogen, and carbon dioxide, but it also has poor water vapor (WVTR) properties. This can, however, be improved with a coating such as PVDC.

Cellophane (cello or cellulose)

At one time, cellophane was the only clear packaging film available, and thus also the most widely used. This material is composed of wood cellulose transfer rather than petrochemicals. Although not used in many modern applications, its compostable property is renewing brand and consumer interest in cellophane, which comes in many versions and has superior dead fold properties and machineability. It does have good natural barrier properties on its own, but the use of coatings can enhance this ability even further.

Polyvinyl Chloride (PVC)

PVC alone is hard, brittle, has low thermal stability, and is practically useless unless compounded with other additives. These additives can include slip agents, plasticizers, pigments, waxes, fillers, processing aids, impact modifiers, and liquid epoxy stabilizers. Specific application requirements will determine which PVC film will be optimal. Most PVC films have high impact strength, scuff resistance, dimensional stability, good opticals, and excellent grease and oil barrier properties. Highly plasticized PVC films have excellent stretch properties, making them good for hand-wrapping meats and produce. PVC films can be made with superior shrink properties, making PVC the preferred material for tamper-evident bands and shrink-label stock.

Polyethylene (PE, LDPE, LLDPE, mPE, MDPE, HDPE)

All of these acronyms fall under the polyethylene family of films, but the films differ so greatly from each other that their applications are completely different, and different polyethylene films are often treated as if they belonged to different plastic families. Most grades of film in the polyethylene family are considered low-cost and have a good moisture barrier, sealability, seal strength, high elongation, and softness. However, PE grade films in general do not have good clarity. PE films are used in a variety of applications such as bread bags, shipping sacks, mulch, frozen foods, consumer products, garment bags, bag liners and more. PE is also offered in white versions and can be coextruded with other resins to enhanced performance of the moisture barrier, lower film sealing temperatures, and increase durability for extreme processing applications.

Foil

Metal foil holds a strong position among flexible packaging materials. Although itself not considered a plastic or film, foil is considered to have the perfect barrier to moisture and gas and also has no light transmission. Foil comes in different hardness or softness levels, with softer foil possessing better dead fold characteristics. Foil is generally used as the inner or middle layer of a multi-ply lamination because it is susceptible to scratching, abrasion and flex crack when exposed. Usually a high-cost material, foil can be difficult to work with in the converting process, but its appeal and superior characteristics can make it a good choice in some applications.

Market Applications and Common Laminations Structures

Note that this list is not all-inclusive, and that each substrate in a lamination can be obtained in a variety of forms and thicknesses. Consider the acronym for each substrate a broad classification with many specific application possibilities based on equipment, processing conditions, barrier requirements, the product being packaged, and more. It is best to consult with experts at Poly Print for help navigating this selection process.

Coffee

  • Polyester/adh/foil/adh/PE
  • Paper/adh/foil/adh/PE
  • Polyester/adh/Metallized PET/adh/PE
  • Polyester/adh/Metallized BOPP/adh/PE
  • OPP/adh/foil/adh/PE
  • Metallied PET/adh/PE

Tea

  • Paper
  • White BOPP
  • Paper/adh/PE
  • Paper/PE/foil/PE
  • Paper/adh/EVOH PE
  • PET/adh/foil/adh/PE
  • PET/adh/metallized BOPP/adh/PE

Rice and Pasta

  • PE/adh/PE
  • Paper/adh/CPP
  • OPP/adh/OPP
  • OPP/adh/PE
  • OPP

Frozen Food

  • PET/adh/PE
  • OPP/adh/PE
  • Metallized PET/adh/PE
  • BOPP/adh/metallized PET/adh/PE
  • PE

Snacks and Chips

  • BOPP/adh/BOPP
  • BOPP/adh/BOPP barrier
  • BOPP/adh/PE
  • BOPP barrier/adh/PE
  • BOPP/adh/Metallized PET/adh/PE
  • BOPP/adh/CPP

Chocolate

  • BOPP
  • BOPP/adh/Metallized BOPP
  • PET/adh/Metallized BOPP

Breads and Cakes

  • CPP
  • BOPP
  • PE
  • BOPP/adh/BOPP
  • BOPP/adh/Metallized BOPP
  • PET/adh/Metallized BOPP

Ice Cream/Novelty

  • BOPP
  • BOPP White
  • Metallized BOPP
  • BOPP/adh/BOPP
  • BOPP/adh/CPP

Cheese, Packaged Meats or Beef Jerky

  • PET/adh/PE
  • PET PVDC/adh/PE
  • PET/adh/PE EVOH
  • Nylon/adh/PE
  • Nylon/adh/PE EVOH

Soups/Sauces/Spices

  • Paper/adh/PE
  • Paper/PE/Foil/PE
  • PET/adh/EVOH PE
  • PET/adh/foil/adh/PE
  • BOPP/adh/Metallized BOPP/adh/PE

Produce (Generally Requires Perforation)

  • BOPP
  • BOPP/adh/CPP
  • BOPP/adh/BOPP
  • BOPP/adh/PE
  • PET/adh/CPP
  • PET/adh/PE

Neutraceuticals

  • Paper/PE/Foil/PE
  • Pet/adh/Metallized PET/adh/PE
  • BOPP/adh/Metallized PET/adh/PE
  • PET/adh/PE
  • Cosmetic Web
  • Stickpack

Pet Food

  • Matte PET/adh/PE
  • PET/adh/PE
  • BOPP/adh/PE
  • Matte BOPP/adh/PE

Lawn and Garden

  • PE
  • Pet/adh/PE

Interesting Facts about Flexible Packaging

  • 80% of the materials in today’s newly-manufactured flexible packaging began as previously manufactured food packaging.
  • Flexible packaging extends the shelf of beef to 23 days (this period is only 14 days without packaging).
  • Flexible packaging extends the shelf life of broccoli to 20 days, as opposed to only 6 days without packaging.
  • Flexible packaging allows for product tracking, which is vitally important when product recalls occur in the market.
  • Industry experts agree that as a direct result of flexible packaging and advanced distribution networks, North Americans enjoy the least expensive food in the world, spending an average of only 11 to 14% of their disposable income to eat, in contrast to European nations, where food costs make up about 20% of disposable income, or less-developed countries, where food can cost up to 95% of family income.