Narrow-web printers are well positioned to produce smaller quantities of flexible packages at very competitive costs. This allows smaller consumer product goods companies (CPGs) to cost-effectively emulate the packaging and graphics of larger competitors and make a real head-to-head challenge for shelf appeal.
The ability to run most structures on narrow-web presses and cost-effectively service short-run requests with quick turnaround times enables brand owners to execute speed-to-market strategies that can effectively take advantage of consumer demand and trends. The fact that narrow-web printers can handle quick changeovers, with a lower plate-to-press cost ratio versus wide-web presses, creates a compelling value proposition.
Once a converter understands the flexible packaging process, it’s fairly easy to add it to the current mix of pressure-sensitive tags and labels. As a guide, the following nine most frequently asked questions will help converters better understand the technical challenges that come into play:
1. How hard is it to convert flexible packaging pouch materials?Flexible packaging typically uses a combination of materials – paper, film and/or foil. Each material has production characteristics that impact the converting process. The combined properties of these materials are designed to protect the package contents – powder, liquid or solid. The majority of these structures will run on narrow-web presses, so integrating the various materials into the existing production mix is easy.
Flexible packaging materials that are thicker in caliper, such as PPFP (Paper/Poly/Foil/Poly) or cosmetic webs – PET (Poly/Foil/Poly) sealant film – have been found to run very well on standard narrow-web presses. However, flexible packaging materials that are thinner in caliper typically are more extensible, and therefore require a normal film press.
2. What press settings should be considered?Paper-faced pouch materials are pre-laminated materials designed to be surface- printed and used to create side-sealed flexible packaging pouches. Due to the thickness and material make-up of these pouch materials, standard unwind and rewind tensions used for converting pressure-sensitive materials will work well.
The paper face of the pouch materials is all semi-gloss quality paper or higher. Line copy, as well as process printing, can be achieved. The only exception is sugar pack material, which is an uncoated paper.
Film-faced pouch materials are also pre-laminated materials and designed to be surface printed. There are two categories of film-faced pouch materials. One is a very thin film that contains either a single layer of film, or two layers of film laminated together. The second is a multiple-film lamination that often contains a metallic barrier layer or foil. The multiple-layer laminations utilize similar web tensions as the paper-faced pouch materials, and are similar to pressure-sensitive material tensions.
The thin-film laminations require a press designed specifically to convert these materials (suitable for applications like single-ply snack web and stickpak) and would include the following requirements:
-- Better tension control versus pressure-sensitive
-- Low-tension unwinds
-- In-feed film friendly
-- Dancer Roll designed for films
-- 1 mil film = ½ pounds per linear inch setting
-- Air brake – transducer feedback (load cell)
-- Web path designed to minimize the stretching of materials to prevent tears and breaks
-- Idler rollers and bearings – low friction, easy turning
-- Minimize any non-consistent friction
-- Reduce idler roll friction
-- High-airflow/low-heat air dryers
-- Proper roll handling
-- Cold UV light system/chill roll or chill drum
Basestock pouch materials offer an alternative to the pre-laminated constructions listed above. Here, the printer has the choice to print a reverse image on a clear top-ply, or to directly print on the basestock. After printing, the clear top-ply is laminated to the basestock using a press-applied lamination adhesive. This process traps the layer of ink under the laminate, which results in superior graphics protection and improved protection for mouth contact, for products like individual sport drinks; eliminates the possibility of ink and varnish contamination transferring to the sealant layer when wound onto a roll; and eliminates any odor transfer to the sealant side from UV varnishes.
3. What FDA requirements are involved?All flexible packaging materials used in food-market applications must be FDA compliant. It is in the converter’s best interest to determine FDA needs and requirements for each application. It is also recommended that narrow-web converters work with their ink and varnish suppliers to meet the FDA requirements of their end-user customers. FDA-compliant varnishes are available. Another way to improve the FDA compliance of the end-user product is to over-laminate.
4. What inks, varnishes and adhesives should be used?Surface printing
Surface printing leaves the graphics exposed to handling and environmental degradation. As a result, some method of protection is required, such as a varnish or over-laminate, to keep the graphics intact. Inks are specific to film versus paper. Film inks are recommended, and are more expensive than paper inks due to the resins used. Films demand lower heat levels, as excessive heat will cause the material to soften or stretch; in addition to higher airflow, chill rolls can be used to keep the web temperature low. Inks must be suitable for the flexible packaging process. During the pouching process, inks will see temperatures up to 375-400 degrees F and, therefore, must be able to withstand that level of heat.
Varnish considerations for surface printing
Varnish must be heat resistant to 400 degrees F when cured. Varnish must be crack-resistan, and it must be low-odor when cure-dried. Converters should contact the varnish manufacturer for brand-specific application profile specifications.
Sub-surface printing refers to printing below the surface of a substrate. Many end users require the graphics to be “buried” or protected to avoid scratching or scuffing during shipping and handling.
Adhesive considerations for laminating sub-surface printed components
Most narrow-web printers use UV adhesives because they offer a short learning curve, good initial and ultimate bonds, and good heat resistance.
In conjunction with material selection, it is important to establish a good manufacturing process, one that ensures proper drying and the right combination of ink, varnish and adhesive.
5. What factors play into roll quality?Key factors include:
-- Flexible packaging film materials are unsupported, so the roll profile must be flat to prevent gauge bands – soft rings on a film roll caused by a slight thickness variation in the film.
-- Thinner films must be free of nicks and damage to avoid web breaks.
-- Because there is no edge-slitting on pouching equipment, edges must be damage-free to avoid additional web breaks.
-- Rolls should always be wrapped, and dividers used, to protect the material during transport and storage.
6. What are some fit-for-use product recommendations?It’s essential that converters use the appropriate flexible packaging material for the application at hand. For example, if a converter is looking to package a dry or wet food, powder ingredient, lotion, oxygen-sensitive product, etc., the material should be engineered to meet the needs of the specific packaging application. In addition, the flexible packaging substrate should offer excellent surface printability for flexo and digital applications.
7. What are the testing requirements for end-use applications?It’s strongly recommended that end users conduct testing on any flexible packaging materials to ensure the material will work in their application. For items that could be considered hard to seal, or that contain oils – like harsh household chemicals, SPF formulas, tanning solutions or cosmetics – it’s suggested that the converter fill the pouches with the ingredients using the sealing parameters recommended for the specific material and conduct accelerated age testing to ensure the pouch material will properly contain the product.
8. How do I find, and work with, contract packagers (co-packers)?A co-packer manufactures and packages goods for other companies to sell. These products can range from nationally known brands to private labels. Finding the right co-packer often depends on the size of a company and the level of service it is looking for.
9. How do I find customers that need narrow-web flexible packaging services?Converters should first mine their existing customer base. It’s likely that if a converter is already doing work for a larger CPG, the CPG may also be using flexible packaging or be in need of the converter’s services in the future to do affordable short-run flexible packaging projects.
Another way for converters to find customers is to join industry associations to further expand their network within the market.
The TakeawayThe flexible packaging process can be easily integrated into narrow-web operations for pressure-sensitive tags and labels by following the technical considerations and recommendations outlined in this white paper. Flexible packaging not only delivers innovative package design, but it also offers the form, function and convenience demanded by today’s grab-and-go lifestyles. Its printing and performance characteristics deliver the recognition brand owners want and consumers trust.
Flexible packaging is expanding, and narrow-web printers have the opportunity to expand their role and business in delivering a broader range of packaging solutions.
Avery Dennison Label and Packaging Materials