Durable labels on a chemical barrel.
By CTM Admin Labeling • labeling systems 0 Comments

Do You Need Durable Labels? It’s Time to Find Out

Are your label materials getting damaged during transit or storage? Will extra precautions help keep your chemical labels legible long after they reach the customer? If either of these answers is “yes,” you may need to upgrade your labels.

A combination of certain materials ensures that durable labels stay intact and legible, even in harsh conditions. Here’s what you need to know to get the right label when testing materials for your products.

What Issues Do Durable Label Solutions Address?

High-quality, durable labels are designed to address five main issues with label failure:

  • Temperature changes
  • Chemical exposure
  • Water exposure
  • Mechanical strain
  • UV exposure

Here are some common scenarios where you need to consider upgrading your labels:

  • Your product requires a Hazardous Communications Standard (HCS) warning label, which must be legible throughout the life of the product.
  • You sell cold beverages that are subject to condensation and may be submerged in water while in a cooler.
  • Your product is often outside and exposed to sunlight, precipitation, and/or major temperature changes.
  • You need manufacturing equipment labels that will last through constant wear and tear and temperature changes.
  • You’re packaging petroleum or solvent products, and your labels need to survive drips and spills from the product.
  • You want to hot-fill containers, so you need labels that can withstand rapid heating and cooling.

What Makes a Label Durable?

Permanent adhesive is strong and flexible enough to cope with temperature changes. This includes the general durability of the adhesive, as well as temperature effects on wet-out times. While an adhesive label may have a wide service temperature range (STR), application temperature ranges are narrower to prevent issues with adhesion. Moisture is also a factor. For example, even though emulsion acrylics work over a range of temperatures, they have trouble adhering to wet surfaces.

Durable label face stock uses heavy-duty materials like polypropylene, polyethylene, or polyester. While paper can be water resistant with the right combination of adhesives and coatings, the most durable labeling products use plastic face stock.

Polyester labels and vinyl labels are popular heavy-duty choices. Each plastic offers different resistance to abrasion, temperature changes, and UV light. Additives are often used to absorb UV light or prevent the breakdown of polymers.

Durable labels also use a thicker top coat than normal or multiple top coats. These elements aid abrasion resistance and make labels more tamper-proof. UV reflective materials are often added to the top coat to protect the face stock, as well.

One thing to note is that this combination of heavy-duty materials makes printing on the label harder. To prevent tears during printing and handling, the standard kraft paper liner may be replaced with machine-finished paper. This paper is stronger, while still offering a smooth surface that helps the label release during application.

Testing for GHS Labels: Protecting Cargo at Sea

If your product needs a Global Harmonized Standard (GHS) label, that label must meet the BS 5609 testing standard. Also known as the Marine Immersion Label Testing Standard, it’s designed to ensure containers lost at sea can be identified when they wash up on shore.

Qualifying labels must survive the following durability tests:

  • Three months of exposure to salt water at mid-tide
  • Three peel adhesion tests:
    • 48 hours after application
    • After 7 days at 60°C (140°F) and two hours at 0°C (32°F)
    • After exposure to salt spray and UV light
  • Color fastness and dimensional stability after salt spray and UV exposure
  • Abrasion testing through exposure to sand and seawater

Testing for Other Durable Labels

Unless you’re packaging something specifically for marine use, saltwater and sand probably aren’t your top concerns. While there is no general standard for label durability, there are a few common tests used to address storage and use issues.

Most chemical resistance tests cover these chemicals:

  • Heptane, a powerful petroleum-based solvent
  • HCL 37% (hydrochloric acid)
  • pH3 (phosphene)
  • Isopropyl alcohol
  • Common cleaning chemicals, including all-purpose and window cleaners

Abrasion wear testing is covered by ASTM standard D7932. Products sold or used in Canada follow the CSA’s C22.2 No. 0.15-15 testing standard.

Abrasion wear is usually tested with a Taber abrasion machine. This device has a rotating turntable for the sample and a pair of abrading wheels. The turntable spins during the test, spreading the abrasion wear across the sample. It has controls to adjust the load and time, allowing repeatable tests that simulate years of real-world abrasion in minutes. These tests can be set up for direct friction using different grit abrading wheels or third body friction (using loose abrasives like sand).

Most adhesion strength measurements are based on ASTM B571 and D2861, which require 90-degree peel tests. After an appropriate wetting-out period, the label is mounted to a sled on a test rig. The sled moves as a cable system pulls on the end of the label, keeping the peeling edge at a constant 90-degree angle. The test measures the pulling force exerted on the cable to calculate adhesive strength.

There are several ASTM standards covering UV testing. Most label testing falls under standard G154, which uses fluorescent light exposure to test color fading. Standards G155, D2565, and D5208 may be used to test the breakdown of plastic face stocks. While not as fast as abrasion tests, a UV test simulates years of exposure in a matter of days.

Can I Print on Durable Labels?

You can print on durable labels as long as you use a thermal transfer label printer and compatible label materials. Thermal transfer printing melts ink onto the label’s surface, creating a permanent bond. This application is useful for adding shipping labels, return address labels, and barcode labels to products. Direct thermal labels aren’t suitable, because they require thermal paper. This paper turns black during long-term storage. Our print-and-apply label applicators handle both types of printing.

We Have the Equipment for the Toughest Labels

Whether packaging industrial chemicals or craft brew sodas, CTM Labeling Systems has the equipment to custom-label your products quickly and accurately. Contact us, and we’ll get you in touch with your local distributor. They’ll work with you to choose a labeling system that works with your production system and your containers.