It’s hard to find a reliable flexible packaging converter. There are more than 400 that would love to take your business, all touting the very best “service, price, and quality.”
It’s even harder for co-packers to establish a partnership with a flexible packaging converter that provides short-run cold-seal packaging. Few offer cold seal, and even fewer offer short runs.
For those who are new to cold seal — and those who aren’t — we’ve developed this four-point checklist to help you choose a long-term cold-seal supplier that can meet the needs of your small-to-medium-sized clients.
Demand that your cold-seal supplier:
- Schedule around your client’s timeline, not theirs
- Design each cold-seal package around your client’s specific needs
- Deliver packaging that’s problem-free and ready to run
- Provide on-site support long after your packaging material arrives
They should schedule around your client’s timeline, not theirs
As discussed in a prior post, many suppliers will offer cookie-cutter solutions to smaller brands, and then group several identical short-run packaging orders together into one, longer run.
Say a midsized client of yours wants their packaging by next week, but your supplier isn’t running their larger, grouped run for another four weeks. With many converters, this means your client won’t get their product for another four weeks.
Co-packers need to demand more from their cold-seal packaging supplier.
First, your cold-seal orders shouldn’t be grouped with other brands — you should have packaging customized to meet your client’s particular needs. And second, they should schedule each of your orders individually, so your lead times aren’t dependent on other brands’ packaging needs.
If it makes sense to group two orders together, great. But your client’s lead times shouldn’t depend on it.
They should design each cold-seal package around your client’s specific needs
Cold seal packaging is complex. And your supplier should take a “one-size-fits-one” approach, engineering practically every feature of the package around your client’s needs and preferences, from the material construction to the adhesive properties.
Your material construction options
There are dozens of film and paper material options, and your supplier will guide you to the right one for your client’s product and preferences. But, generally speaking, there are only two cold-seal packaging structures: Monolayer and multilayer.
Monolayer cold-seal packaging is comprised of a single material, usually paper or white film. Graphics are printed on the top surface of the material and the cold-seal adhesive is applied to the back.
On monolayer constructions, a release lacquer is applied on top of the graphics, serving two purposes: Protecting the ink from abrasion and allowing the bottom of the film (which is coated with cold-seal adhesive) to release quickly and entirely.
Multilayer cold-seal packaging is most commonly a two-ply adhesive lamination, consisting of an outer film with the reverse-printed graphics and a base film coated with the cold-seal adhesive.
- Outer film
The graphics are reverse printed on the outer film before being laminated to the base film. While the bottom of the outer film is treated so it bonds with the lamination adhesive, the top surface is left untreated — so it won’t adhere to the cold-seal adhesive on the bottom of the base film.
- Base film
This film is laminated to the graphics side of the outer film, and then the cold-seal adhesive is applied to the bottom of the two-ply film lamination.
Monolayer structures eliminate the need for the lamination process, making it a cost-effective choice that’s sufficient for many candy and snack products. And multilayer structures combine two films into one inseparable web, forming a finished structure stronger than either of the individual materials alone.
So which structure is better?
The one that meets the cost, performance, and aesthetic needs of your client. Your cold-seal supplier will guide them in the right direction.
Achieving the right adhesive properties
Cold-seal adhesive is predominantly comprised of natural rubber latex, with modifiers (plasticizers, resins, polymers, etc.) added in to fine-tune its properties (hardness, adhesive properties, etc.).
Your cold-seal adhesive has two primary jobs: Anchor to the material on which it’s applied (called specific adhesion), and “fail” in the desired way. To clarify, all packages “fail” — they peel open easily or are destroyed in the process — and different modes of failure can be preferable depending on what your client needs out of their package.
Your cold-seal supplier should be able to design around all three modes of failure:
Imagine you’re opening a candy bar. In this mode of failure, the package doesn’t peel at the seam — but rather the material itself is destroyed when the consumer opens it, making it evident if a product has been tampered with.
The package peels open at the seam and the adhesive itself is split apart, leaving cold-seal adhesive on both sides which can make the package recloseable.
With adhesive failure, the package peels open at the seam, leaving cold-seal adhesive only on one side and giving the package tamper-evidency.
Great care must be taken when designing the package to ensure the finished package runs, looks, and performs as intended. Choose a supplier whose one-size-fits-one approach to packaging design ensures these needs are met for every packaging order, without fail.
Your packaging should arrive problem-free and ready to run
It’s a reasonable request: Your packaging should arrive ready to run on your HFFS packaging line without issue.
Still, there are a lot of processes that go into making cold-seal packaging. And there are two major problems co-packers might face when running cold-seal packaging — both of which are easily prevented if your converter has the right quality control measures in place.
Cold-seal adhesive is applied in a pattern on the back of the film lamination, precisely in-register with the graphics on the front. When doing this at very high speeds, occasionally a portion will be skipped, meaning no adhesive was applied.
Your supplier should use an inline camera system that visually inspects the web for skips in real time, and also manually do quality checks from each roll. These measures ensure packaging rolls with skips never make it out of their facility and onto your packaging line.
Cold-seal adhesive is predominantly natural rubber latex and, if handled improperly, can go rancid, giving off an unpleasant odor and growing bugs and mold.
This is obviously a huge problem. Not only does it lead to expensive packaging waste, but there’s also the chance that rancid, odorous packaging could reach your client, or worse, the consumer.
These are unacceptable scenarios for co-packers — and they’re also entirely preventable if the converter follows best practices when handling the adhesive.
Cold-seal adhesive, for example, should never be stored in a half-full drum. If only part of the 55-gallon drum is used during a run, the remainder should be separated into smaller pails to minimize the headspace between the top of the container and the surface of the adhesive. Leaving it in the original drum allows the air to interact with the product, which will ultimately cause it to spoil.
Your converter should follow all prescribed storage conditions from their cold-seal adhesive supplier to prevent these problems. They should also educate you about how to store the packaging at your own facility.
They should provide on-site support long after your packaging material arrives
Your cold-seal packaging supplier’s job is far from done when your order arrives. In fact, it’s just begun.
Especially when you first start running your cold-seal packaging, they should be on-site, educating your team, observing your operations and troubleshooting any problems.
At C-P Flexible Packaging, we’ll send a technical service representative to your facility. They’ll audit your operations and, as needed, offer recommendations for optimizing your runs and increasing your throughput speed. If a roll needs to be repositioned or a machine setting needs to be changed, we’ll be physically there and doing it.
You should demand this kind of boots-on-the-ground support from your supplier, so you can focus less on packaging line issues and more on making your clients’ snacks, bars, and candies.
Get your guide to cold-seal packaging
Short runs of cold-seal packaging are now possible, and the potential for this technology to differentiate co-packers to the midsized clients they serve is too great to ignore.
We created a guide for co-packers that are either considering adding cold seal to their product portfolio by establishing a strategic partnership with a cold-seal packaging supplier, or those that are having trouble with their current supplier. Download your copy today.