How the Right Cold Seal Adhesive Supplier Gives You a Competitive Advantage

As brand owners face pressure to produce more sustainable packaging into the market, it can be challenging to keep up with changing regulations and sustainable certifications. For example, How2Recycle, the leading sustainable certifying body in the U.S., now requires cold seal adhesive to be tested for recyclability when applied to flexible PE film. This means any suppliers that have cold seal adhesives with labels or prequalified How2Recycle letters from May 2022 or prior could be investigated if they do not retest. Further, if you don’t communicate this change with brand owners, it could cause them to advertise sustainability capabilities that are no longer true, causing complications to the recycling process if end-users are recycling items that are no longer deemed applicable.  
 
The right supplier can help you address changing regulations to improve recycling 
 
Suppliers who know the importance of enhancing recyclability understand a certification like How2Recycle is crucial to ensuring confidence for converters and brand owners. Therefore, the right supplier will be quick to act on this change, determining again whether their cold seal adhesive meets recyclability requirements for the flexible PE recycling stream.  
 
Further, the right supplier will test with more than one organization to ensure they are meeting the necessary recycling standards. Along with regaining pre-approval from How2Recycle, they will also ensure their cold seal adhesives meet the Association of Plastic Recycler’s (APR) critical guidance testing using a third-party lab. They will use the most difficult combination of factors to pass, such as product choice and coat weight. This helps you and your brand owners know your supplier’s cold seal adhesives meet performance needs for the most stringent situations. When creating or designing new sustainable packaging, partnering with a supplier that goes above and beyond with testing gives you assurance your package will pass the U.S. sustainable certifying bodies’ requirements, while also saving you valuable resources to complete the testing yourself.  

Throughout the manufacturing process, there are certain times when there’s potential for cold seal adhesives to coagulate, which could impact the adhesive performance:  
 

• Storage: Cold seal adhesives endure three processing stages that include wet storage, converting and product packaging. Each of these stages involve different storage recommendations. For example, when the cold seal adhesive is in wet form, it needs to be stored above 40°F (4°C), as it is not freeze-thaw stable and needs to be discarded if coagulated. Requirements like this can be difficult to monitor closely during a complex production, especially if the cold seal adhesives sit in the wrong temperatures for prolonged time periods.  
• Processing: Most cold seal adhesive formulations contain NRL, which is a shear thickening raw material. This means the viscosity will increase under stress or pressure, which can make it difficult to process cold seal adhesives. If you apply more shear to NRL, it will coagulate from a liquid to semi-solid, resulting in additional downtime to address while converting. While finding a cold seal adhesive formulation without NRL may seem like the solution, NRL is necessary later when a product is being packaged to ensure fast line speeds. This may force you to spend additional time finding which methods are best for you to reduce or eliminate shear in your converting Further, if you don’t solve the problem, it can affect the end-use package performance and lead to more material waste from unusable products getting disposed.  

The right cold seal supplier will help you mitigate cold seal adhesive coagulation 
 
The right supplier will have the expertise to either help you troubleshoot or provide solutions before you’ve even asked about it. This includes offering: 
 
Shipping protection: The right adhesive supplier can alleviate your concerns by shipping cold seal adhesives in heated trucks during the winter months, ensuring the weather does not impact your supply before it arrives to your facility. Further, a supplier can include a freeze indicator on every pallet through winter months to help you track any potential issues. A supplier can also use specific shipping schedules to ensure cold seal adhesives do not sit in a storage container or on the dock for long periods of time during winter months. 

Storage temperature recommendations: The right supplier will know how a cold seal adhesives should be stored throughout your processing steps. For example, once the cold seal adhesive is in converted roll form, it can be exposed to low and high temperatures. These rolls should be stored above 25% relative humidity to protect the bond strength. If you realize these storage methods were not met properly, the right supplier can share ways to reverse the problem to recover the bond strength.  

Shear reduction methods: While it’s important to include NRL in a cold seal adhesive formulation, the right supplier will know ways that you can reduce shear, which includes: 

• Removing all latex-based tubing from your cold seal adhesive station 
• Increasing the doctor blade angle 
• Adjusting the mixing speed of the holding tank 
• Cleaning the equipment of any dried cold seal 
• Cleaning while the press is running 

This will prevent the NRL from sticking to itself. They can provide training to ensure cold seal adhesives are converting at high line speeds, which will include showing you where build-up occurs the most and which holding tank pumps reduce shear the best.