Heat Sealing vs. Cold Sealing: What’s The Difference?

Heat Sealing vs. Cold Sealing—this is a tete-a-tete most people aren’t aware of.

If you're a new manufacturer, the type of seal is often a crucial decision you might have pushed down the list in favor of product development and packaging design.

While a seemingly small detail, the type of seal you choose determines the longevity of the shelf-life of your products.

Fail to choose the right seal—you risk losing business through product spoilage and recall due to quality issues.

To avoid unnecessary stress and losing capital, your products must stay in their packaging safely using the correct type of seal.

Heat Sealing vs. Cold Sealing: Why Should I Look Into Seals More Intently?

Especially in food packaging, the seal area is typically the most problematic aspect because this regulates the entry of gas and moisture. Why is this a critical role?

As a goal, sealing your products doesn't end at simply closing the package. Seal quality and seal integrity must work together to deliver BOTH protection and easy usage requirements.

Truly under-appreciated, understanding how a seal mechanism works is vital in preventing product spoilage and guaranteeing consistent food quality and freshness while stored and not sold or consumed yet.

But how do you know what sealing method is the most suitable for your particular product?

And what is better, in your case: melding sealant layers using heat and pressure or applying cold-seal adhesive coatings to packaging film?

Heat Seal or Cold Seal For Your Product Packaging?

Flexible packaging is now the gold standard for various industries. Many companies have turned to flexible packaging because it gives them many customization options. You can seal these protective, flexible packaging films using pressure-sensitive adhesives with and without heat. 

So, when creating your next packaging pouch or mylar bag, you must choose between heat and cold seal adhesives.

Can you just flip a coin to pick? Is it wise to simply choose what turns out to be the more budget-friendly option? These two options are each best suited to specific product requirements.

Therefore, it is crucial to understand the merits, disadvantages, and applications before you decide.

This post will discuss the differences between cold and hot sealing, and we will also explain how each works and compare the two.

Which Type of Sealing Method Is Best Suited For My Products?

Flexographic and gravure printing technologies are used to create flexible packaging. It is essential to understand and test the sealing conditions for flexible packaging inks before use.

To be clear, both heat-sealing and cold-sealing processes are reliable ways to ensure that your products remain fresh. However, determining the suitable sealing method for your product depends on certain elements.

The most important are: your product's individual requirements, such as machine capacity and speed, your packaging's seal strength, and barrier ability (e.g., UV radiation, moisture, and oxygen). 

We will review heat sealing first. Get your checklist out and compare notes to keep your requirements in front of you as we start discussing each kind of seal method. 

HEAT SEALING

What is a Heat Seal, and What is the Heat Sealing Process?

A heat seal in flexible packaging helps to protect products from damaging environmental factors, product contamination, and consumer tampering.

Heat sealing is the best solution to develop high-integrity, airtight seals. To create a successfully heat-sealed package, we determine the area where the closure should be and then fuse flexible packaging film material layers in that area via pressure and controlled heat.

How Does a Heat Seal Look Like?

Heat seal films, which are available in a range of laminations, also have a more comprehensive range of performance characteristics than cold seal films.

Let's take a look at how we build this type of seal. Three separate, functional layers make up a proper heat seal: an internal sealant layer, an outside layer, and a core layer.

What Creates the Perfect Heat Seal?

Heat seal technology is an adhesive that requires constant, homogeneous heat distribution, pressure, and dwell time to be effective. To establish an efficient and secure heat seal, we carefully control the three mentioned variables with our machines.

To create the perfect heat seal, always place your filled packaging inside the seal jaw (between the seal bars), ensuring these are on top of your tear notches.

If you heat-seal your packaging in-house, make sure you follow your machine's directions.

Can I DIY Seal Packaging Using a Hot Iron? 

Some people use an old curling iron or flat iron to seal their packaging pouches. This works and can be a good solution if you are on a lean budget and sell products in small batches with a high turnaround. 

However, consider investing in a proper heat sealer if you deal with larger batches and have particularly perishable products that need to sit in storage for a longer time.

Compared to cold seal adhesives, heat seal binders offer a secure seal and smooth peel effect. Cold seals are easy to use and bond instantly; however, they are permanently tacky and require silicone release paper.

Proper heat seal packaging does not necessitate using any unique techniques or substrates; therefore, it is more economical.

HEAT SEALING: Applications in Flexible Packaging

We can apply heat-sealing on different types of flexible packaging, including coiled tubing, film canisters, sacks, boxes, bottles, and jars.

The most common types of seals used for heat-sealing are hermetic (tightly closed), mechanical (in which the seal is created by pressure), or thermal (by using a heated sealing device).

There are many different ways to apply heat-sealing technology in flexible packaging; some typical applications include overwrapping, overpackaging and secondary wrapping.

We use heat-sealing technology for a wide range of products, including foodstuffs, beverages, cosmetics, and pharmaceuticals.

COLD SEALING

Now that you understand what hot seals are about and how they work, let’s take a look at cold seal adhesives and see if they are what will work best for you.

What is a Cold Seal, and What is the Cold Sealing Process?

A cold seal is a water-based adhesive coating that is used to seal paper and packaging substrates. The word ‘cold’ is used to indicate that no heat is required as all you need to create a bond is to apply pressure.  

The cold sealing process involves two films, one of which allows you to print product information on the backside. The two films are then sealed to create an unbreakable bond. After this, the cold seal adhesive is applied to the inner side of the bonded films. 

How Does a Cold Seal Look Like?

If you have ever seen some adhesive residue after peeling your chocolate bar wrapping, it is very likely that the packaging was sealed with a cold adhesive. 

What Creates the Perfect Cold Seal?

The strength of the bond may vary based on a number of factors, the most prominent of which is the composition of the adhesive. Also depending on the product being packaged, different bond strengths are available.

The weight of the coating also significantly impacts the bond; the lower the coating weight, the weaker the bond and vice versa. The amount of pressure applied and whether the jaw is flat or crimped have a major impact on the bond strength. 

About Cold Seal Adhesives

Cold sealing is more suitable for sealing heat-sensitive products. To give you a clear example: If you are packaging chocolate bars, this would be your best package sealing option to make sure we keep the correct consistency of your freshly-produced product.

The glue is generally applied wet to the material by a spinning gravure cylinder and quickly dried in an oven before being rolled down to the press’s finish. Cold seal adhesives don’t require heat to seal up.

IMPORTANT NOTE: Since cold-seal is a natural substance, it is intrinsically inconsistent and if not handled correctly, it can be quite unstable. Only qualified professionals with a specific understanding of the adhesive can be able to use it. If by now you’re convinced that the best way to package your products is with cold seals, contact us so that we can help you finalize all your technical details.

Application of Cold Adhesives 

INSERT AN IMAGE OF PRODUCT(S) THAT HAVE BEEN COLD SEALED

If you’re still on the fence and wondering whether you could use cold adhesives for your specific needs, let’s now go ahead and discuss specific applications to make it much more clear for you.

We use these adhesives for a variety of products and packaging, the most common of which are:

  • Confectioneries/Desserts: such as ice cream, chocolate bars, candy bars, caramel squares, gumdrops and gummies, cotton candy, lollipops, and sours.
  • Smaller self-seal envelopes for sampling campaigns and gondola ends in the supermarket
  • Medical equipment and materials: such as bandages and gauze

Have you ever heard about “self-seal adhesives”? It is a term that is used interchangeably with cold-seal adhesives. It is used to refer to the unique feature of cold adhesives that enables them to seal only to themselves.  

Depending on what you want to be sealed, the amount of pressure applied differs, thus creating varying bond strength.

In most cases, cold sealing involves the use of two films; one film has the print branding (company’s logo and graphics) on its reverse side while the other serves as a protection for the item inside.

The cold seal is then applied to the interior surface of the web in a pattern that matches/aligns with the graphics on the exterior of the web.

Many temperature-sensitive confectionary items (e.g. candies) are packed and secured with cold seal adhesives which are made of a cold seal release lacquer (CSRL) and a surface printed ink.

IMPORTANT NOTE: While formulating the inks for cold seal packaging, avoid using any kind of fatty amide or PFE waxes. If these come into contact with the adhesive for any length of time in the printed roll, they might compromise the quality of the adhesive.

Getting it right from the very beginning is very critical. The films should be compatible with the adhesive. Incompatibility between the substrate and the adhesive could result in a weak bond or no seal at all.

Benefits of Using Cold-Seal Adhesives

  • Unlike hot seals, cold seal adhesives do not require heat to form a bond. 
  • There being no need for heat, burn-related injuries are the least of our worries. 
  •  Cold seal adhesives are FDA approved for direct food contact.
  • Since they have a low odor, you don’t have to worry about the impact they could have on your product’s flavor.
  • If the packaging line malfunctions when the packaging process is underway, heat-sensitive items remain undamaged.
  • Energy costs are also comparatively lower since there is no need for high sealing temperatures.
  • This means that the packaging process is relatively fast. Cold seal packaging can be multiple times faster than heat seal packaging since we don’t need the dwell time for the packaging equipment to heat up.
  • Cold sealing allows for promotional information to be printed on the packaging.

Guarantee Secure Packaging That Won’t Let You Down

Are you a small or medium business? Don’t be obliged to accept packaging that falls short of your expectations; you can still have the best packaging services for your items despite being on a smaller budget.

At Pouch Me, we understand the difficulties that our clients experience when launching a new product in the market or promoting it to increase sales. We also help large enterprises maintain their brand image by ensuring that they have high-standard packaging for their products.

Whether you require large or small quantities of cold-seal product packaging, we are ready to help. We will assist you through the designing process until your items are packaged and ready for shipment. 

Can Cold Seal Packaging be Run on a Heat Seal Packaging Line?

Yes, it is possible to create a cold seal bond on the heat sealing machine. Since it is possible to adjust the heat levels on the line, all that needs to be done is to turn the heat off. 

Sealing for Sustainable Packaging For Food and Non-Food Products

Customers, as well as manufacturers, have become increasingly conscious and mindful of how their choices impact the environment? Sustainability is one key issue that you need to consider when packaging your goods. 

You may have considered using recyclable packaging materials but are wondering whether it’s possible to separate the adhesive from the material. We have good news for you—it is possible to recycle some materials that have previously been sealed using cold or heat adhesives.

All you need to do is give us a call, let us know your requirements, and we will help you figure out what works best for you.

Seal It Together

With the cold seal adhesive, there is no need for other packaging supplies like sealing tapes, corrugated boxes, bubble wraps, plastic cartons, and more.

It keeps the product free of adhesive residue with its unique packaging approach. Both film and cold seal must be compatible in order to produce a successful seal. The film and seal must be compatible to prevent blocking.

We can’t leave anything to chance. Poor package seals can lead to leakage or even food spoilage. This is detrimental to your brand image as it stands to ruin your brand reputation and also highly likely to cut sales.

Let’s Start With What You Need

As stated above, both cold seal and heat seal have their merits and drawbacks. Each one is better suited to certain purposes. 

As you look for the best sealing procedure for your goods, bear in mind that when you Pouch Me with our Production, Design, Prepress, and Service Teams, you receive the correct specifications for the packaging material that best suits your products.

To get started on the journey towards getting your unique flexible packaging, contact us today. Allow our well-trained team the pleasure of securing your products and making you stand out from the crowd.


- Heat Sealing and Cold Sealing: What is The Difference? FAQs -

  • What is heat seal coating?

Heat seal coatings are thermoplastic coatings used in packaging products. These coatings are adhesives that can be applied to various laminates and packaging films.

The intent is to ensure that they cling to a variety of materials by forming a seal using pressure and heat. Heat seal coatings guarantee airtight seals, so they are perfect for a wide range of products and applications.

  • What is cold seal lamination?

Cold seal lamination involves the application of adhesive in a pattern to the backside of the packaging substrate. Unlike heat seal lamination, cold sealing is designed to stick to itself without applying a lot of pressure.

Due to the technicalities involved, cold-seal requires specialized knowledge. Improper handling may result in tremendous waste, which can lead to high costs.

  • What is cold seal packaging?

Cold seal packaging is a process that involves placing a frozen product into a specially designed bag and then sealing it with a heat seal.

The recently sealed product is then placed in a freezer, where the temperature is below -5 degrees Celsius. The product will stay frozen for up to a year, which is long enough to keep the product fresh and avoid the issue of product spoilage.

  • What is the difference between heat seal and cold seal packaging?

The main thing that sets cold sealing apart is that the adhesives only seal to themselves. When a cold seal adhesive-coated material gains contact with another material coated with a cold adhesive, they form a strong connection with the application of standard manual pressure. This is why the terms "cold-seal" and "self-seal" are often used interchangeably.

Heat sealing produces a more durable product than cold sealing since heat sealed products are typically more secure and airtight.

  • What are the advantages of heat seal and cold seal packaging?

Cold seal packaging tends to be more efficient in terms of energy usage because it doesn't require as much heating up as heat seal does.

Heat seal packaging tends to be more environmentally friendly because it doesn't require any additional power or heating up, which can help save on energy costs.

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