Adhesives 101 for Packaging Designers

Adhesive technology has come a long way in the past decade, providing packaging designers with ample opportunity for amazing designs that are at once both eye-catching and functional. The right adhesives can help you create safe, easy-to-open packaging (if that’s your desire, of course), while ensuring that your product stands out on the shelves.

Understanding the different types of packaging adhesives and their uses will help you create cost-effective, show-stopping packaging for any product.

Types of Adhesives: The Basics
Packaging designers know that the variety of adhesive technologies on the market can be overwhelming. Not all adhesives are ideal for every application, and some are more versatile than others. All of the adhesive types listed below are commonly employed in packaging applications, from sealing cartons to labeling.

• Pressure sensitive adhesives (PSAs) hold two materials together via contact and physical pressure. This type of adhesive acts as a permanently tacky bond, allowing the user to easily separate the two materials. It’s appropriate for sealing plastic, paper, metal, glass, wood and other substrates, and is a popular choice for labeling food packaging and bookbinding.
• Also known as “credit card glue” or “gummy glue,” this adhesive differs from pressure sensitive adhesive because it provides a temporary bond. Packaging designers can use fugitive glues in marketing applications, such as any scenario where you want to attach flyers, coupons, samples and other items to another surface, without damaging the materials.
• EVA adhesives are generally applied with the use of a commercial hot melt gun, and are solid at room temperature until they’re heated up and melted. These glues are ideal in a ton of packaging applications because they offer a fast set time, a long shelf life and functionality across many temperatures. Because these adhesives easily adhere to waxes, paper, stock and aqueous coating, they’re always a preferred choice for packaging applications.
• Metallocene Hot Melt Adhesives — Like EVA adhesive, metallocene (also called polyolefin) is dispensed via a hot melt gun and is solid until applied. Many people prefer metallocene over EVA because it has little to no odor and is extremely clean-burning. Additionally, metallocene hot melt adhesive is known for bringing minimal or no stringing, which can compromise bond strength and make a mess.

Water Based vs. Hot Melt Adhesives
Another thing you should know before settling on a certain packaging adhesive is that there are two main types of adhesives to consider. Water-based adhesives — including latex, starch, protein and resin adhesives — are not nearly as common as hot melt adhesives, but they do have a few primary benefits. These adhesives differ from hot melt adhesives in several ways, but the primary difference is that they come in powders or solutions that must be mixed with water.

Many people prefer water-based adhesives in packaging because they provide some benefits over hot melts. For example, some water-based bonds have a faster set time than hot melts, so they are preferred in packaging in the beer and wine industry.

With that being said, hot melt glues are certainly the gold standard. The ability to set quickly, coupled with strong resistance properties, makes them desirable, but they do require hot melt glue guns for application.

Understanding Adhesives for Food Packaging
Choosing the appropriate food packaging adhesives will help ensure that your product arrives safe, fresh and up to regulated quality control standards. We recommend getting to know the terms in this food safety packaging glossary to understand the different rules, regulations and recommendations that are required in food packaging. This will help you decide which type of adhesive is best-suited to your food- or beverage-packaging needs.

For example, solvent-based adhesives can be a good choice for certain food packaging jobs, but the adhesives must be fully dried after applying so that they don’t influence the smell and taste of the food. In other words, if you choose a solvent-based bond for your food packaging, it’s essential that you opt for one with a fast drying time. And, of course, toxicology is a big factor when considering food-grade adhesives, so you want to make sure your glues are non-toxic or used in a way that doesn’t expose them to the product.

Solving Packaging Issues with Adhesives
Packaging designers have different goals. For some, it’s about creating food-safe labels that won’t become damaged when exposed to extreme temperatures. For others, it’s about eliminating “wrap rage” for consumers, without risking damaging a carton’s contents. Here are some ways to fix various packaging issues with adhesives.

• Creating Easy-to-Open Packaging — One of the toughest things packaging designers are faced with is finding packaging solutions that are easy to open and secure at the same time. You don’t want to force consumers to use a knife or another sharp object to open the package, as this could damage its contents, and over-sealed packaging can be incredibly frustrating for the end user. In addition to the type of adhesive used, achieving secure, easy-open packaging is attainable with the right bead profile.
• Adhering Hard-to-Bond Surfaces — It’s a good idea to implement unique materials into your packaging, and certainly helps it draw attention on the shelves. But what about when these materials don’t take well to adhesives? High-gloss paper, wax, clay-coated materials and metallized PET are notoriously hard to bond, so finding the appropriate adhesive for the job is key. Hot melts are often the answer to these issues, and your adhesive supplier will be able to recommend the right one.
• Finding an Adhesive That Doesn’t Drain Your Budget — Another incredibly important factor in choosing the right adhesives is cost. You need to find a product that checks off all of your requirements but doesn’t catapult your packaging costs through the roof.

Packaging experts recommend performing various tests — including studying different adhesives, adhesive patterns and packaging materials — to find a cost-effective bond that meets all of your needs. Of course, operation and equipment plays into efficiency and cost, too, so make sure to take them into consideration as part of your testing.