You spend hours perfecting copy and design.
Yet one weak seal ruins the reveal. Worse, it can jam inserting lines or fail postal tests.
As a packaging expert at Pakoro, I’ll show you how to avoid that mess and keep your mail—and your reputation—intact.
1. Remoistenable Gum
“Lick, press, done.”
That simple ritual still powers billions of mailpieces every year.
How it works: A thin, water-soluble adhesive coats the flap. You—or your automation unit—add a mist of moisture. Once the flap meets the body, fibers lock together and stay shut.
Why you’ll like it
- First, it’s dirt-cheap.
- Second, it fits nearly any envelope size, especially the popular #10.
- Third, it stores well for years when kept dry and cool.
When to skip it
If you run ultra-high-speed inserters, the added wetting step can slow you down. We’ll fix that in the next section.
2. Latex Gum
Latex gum—also called self-adhesive gum—is pressure sensitive. You press; it bonds. No water. No mess.
Three Formulas, One Goal: Faster Workflows
- Seal ’N Reseal®
Great for photo or document wallets that clients open many times. The flap re-closes without tearing fibers. - Touch-’N Seal®
A single-use version you’ll see on banking envelopes. Once sealed, it stays shut. - Peel-n-Seal
Here a strip of release paper keeps glue fresh. Remove the liner, press, mail. Big upside: zero tackiness on the production line. Big caveat: not compatible with automatic inserters, so consider manual runs only.
Shelf-life reminder: All latex gums degrade over time. Store cartons flat in a climate-controlled room and rotate stock every six months.
3. String & Button
You’ve likely seen this closure in movies—two paper discs, one sturdy string. Twist, tuck, untwist, repeat. Ideal for:
- Finance or HR files that circulate between departments
- Sample kits that sales reps reopen during demos
- Luxury gift cards where tactile value sells the experience
Yes, it costs more than a simple gum line. But the reusability factor makes it a smart pick for internal workflows or premium launches.
How to Choose Quickly
- Define the job. Transactional mail? Marketing kit? Interoffice folder? Purpose guides closure.
- Match equipment speed. If your inserter runs 12,000 pieces per hour, self-adhesive wins. For manual small batches, remoistenable saves money.
- Audit brand cues. Do you want a clean edge or a retro string vibe? Every detail speaks for you when the customer grips that flap.
Need a fast sample? Contact our team. We send blank dummies within 24 hours, worldwide.
Common Questions
Q: Will remoistenable gum trigger postal moisture tests?
A: Not if stored at 35–50% RH. Pakoro ships cartons inside poly liners for extra safety.
Q: Can I run Peel-n-Seal on a Sitma 950?
A: No. The release liner jams feed rollers. Choose Touch-’N Seal® instead.
Q: Are string-and-button envelopes recyclable?
A: Yes. Remove the string (textile) and recycle the paper shell as mixed office waste.
Ready to Seal the Deal?
A flawless closure protects more than paper—it protects trust. Partner with Pakoro to specify, test, and ship envelopes that arrive perfect every time.
One click and we’ll run a free closure compatibility check on your next design. Talk to a Pakoro expert now →
