Understanding Adhesive Technology: Acrylic vs. Butyl ...

As building science evolves, the products and techniques we use evolve too. In the building products space, one of the most recent and notable advancements is adhesive technology in flashing. While butyl- and asphalt-based adhesives used to be the go-to products, newer, acrylic-based technology are becoming the gold standard.

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Understanding the differences between the main types of adhesives can help builders and contractors determine the right choice for their projects. Some of the most important factors to consider include climate zone/temperature, possibility of moisture intrusion, budget, efficiency, and quality of the product.

Below, is an overview of the three most common adhesive technologies and the basic advantages and disadvantages you should consider.

Acrylic

While relatively new, acrylic-based adhesive products are quickly climbing to the top. Typically comprised of acrylic or methylacrylic polymers, these adhesives are lauded for their cohesion, adhesion, and viscosity.

Advantages:

• Long-term UV stability.
• Long-term bond that cures over time, meaning it can be repositionable upon initial install but will become stronger over the course of its life.
• Can be installed in a broader range of temperatures.
• Unaffected by temperature fluctuations over the course of its life.
• High cohesion rate, ensuring that it remains bonded over its lifespan.
• Does not transfer colors to other materials.
• Can be vapor permeable depending on the formula and application method
• Available in multiple forms (tape and liquid-applied).

Disadvantages:

• Sensitive to surface moisture upon initial install; using a liquid-applied acrylic adhesive would be better in these conditions.
• Typically a higher price point than other adhesive alternatives.

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Butyl

Butyl-based and &#;butyl-hybrid&#; technologies are made of specialized, synthetic rubber and were specifically designed to combat the disadvantages of natural rubber adhesives.

Advantages:

• Strong initial tack.
• High level of adhesion due to its ability to bond to most substrate materials.
• Relatively economical.

Disadvantages:

• Not repositionable, and therefore less forgiving if not placed perfectly the first time.
• Physical makeup may be altered by high or low temperatures. For example, can become fluid in high temperatures and solid/stiff in colder temperatures.
• Can dry out and become brittle over its lifespan, especially if it experiences multiple thermal changes.
• Can transfer color or adhesive to other surfaces.

Asphalt

Initially used in roofing applications, many contractors began using asphalt-based, or modified bitumen, adhesives as a primary flashing solution. The popularity of the product is due to it often being the cheapest option, but the low cost doesn&#;t justify the lack of quality that comes with these types of adhesives.

Advantages:

• Cost-efficient.

Disadvantages

• Successful adhesion can only happen in a very small temperature window.
• Breaks down and becomes brittle quickly.
• Can transfer color or adhesive to other surfaces.
• Can introduce major issues and compromise the integrity of the wall system due to its lack of compatibility with other products.
• Often voids window manufacturer warranties if used for window penetrations or integration with window flange

Understanding the benefits of each adhesive type can help you properly balance installation quality and cost for long-term performance. Despite acrylic technology being newer to the industry, the advantages point toward it being the most ideal option in most circumstances.

Want to know more? Let&#;s get visual! Check out our latest video where we tested the adhesive strength of a butyl-based adhesive vs. an acrylic-based adhesive over a 36-hour period.

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October 22,

Sometimes you want an adhesive that&#;s modestly sticky and easily reversed&#;like a sticky note.  Other times, it needs to be darn near irreversible.  High-performance building contractors also need to consider adhesive tapes capable of withstanding temperature extremes and volatile moisture conditions; adhere to a wide variety of substrates; and tolerate the dust and dirt found on the surfaces of the building materials or the job site.  Is that acrylic or butyl? Silicon or rubber? Here&#;s what you need to know.

What Are the Types of Adhesives Used in Tape?

That said, there are four basic types of adhesives used in tape all of which differ in characteristics as well as cost.

Rubber: Adhesives that are based on natural or synthetic rubbers and formulated with tackifying resins, oils, and anti-oxidants. Rubber is often the most cost-effective adhesive and offers quick stick capability. Rubber adhesive is not recommended for high heat applications. It also does not perform well in colder temperatures, especially if it reaches below the freezing point of 32°Fahrenheit.

Butyl: A specialized rubber adhesive system, butyl was developed to augment traditional rubber adhesives because they are less temperature-sensitive and maintain their tackiness at much lower temperatures than natural rubber.  And while butyl sticks better to more substrates, butyl is also more expensive.

Acrylic:  Acrylic adhesives can be water-based, solvent-based, or &#;solid.&#; Water-based adhesives are the least expensive of the three and generally do not bond to as wide a variety of substrates as solvent-based ones. Solid acrylic adhesives can form the strongest adhesive bonds at a wide range of temperatures and even achieve adhesion to damp or wet substrates. Solid acrylic adhesives are also VOC-free, and the absence of any solvents means little to no embrittlement of the tapes over time. Both water- and solvent-based acrylics are similar in cost to butyl rubber tapes; however acrylic adhesives typically develop a stronger bond than the traditional Rubber adhesive and are able to take higher temperatures

Silicone: Formulated with Silicone polymers and the only adhesive that will bond well with silicone substrates. Silicone adhesives are relatively expensive and have a very low initial tack, but can withstand higher temperatures than both Rubber and Acrylic adhesive

So, which is the best fit for your application?  Well, for builders and professional contractors, it really comes down to butyl and acrylic. So let&#;s take a closer look at these two popular adhesive technologies.

What Is Butyl Tape, Exactly?

Butyl tape is an example of a synthetic rubber adhesive. It&#;s a solvent-based adhesive that is formulated in the lab instead of coming from a rubber tree. All types of rubber adhesive are thermoplastic, so exposure to high heat will soften the adhesive and impact its effectiveness. However, butyl adhesives are formulated to be less sensitive to temperature variations. They stay more flexible in cold weather and more stable in high temperatures than natural rubber adhesives. Because butyl tapes are extremely durable,  with have good flex properties, they are often used in applications where an airtight bond is required. In fact, most butyl tapes also come with a liner since the adhesive system is aggressive and forms a permanent bond to the surface it sticks to &#; even if that surface is itself!

When Are The Advantages of Butyl Tapes?  

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Advantages:

High initial tack­&#;has a more aggressive hold on contact than acrylic adhesives

Has a high level of adhesion because it bonds to a huge variety of surfaces

Less expensive than acrylic adhesive

Impermeable to air

Waterproof so it works well in situations where water is a factor

Disadvantages:

Even though butyl adhesives are less sensitive to temperature variations they still cannot match the range or performance of acrylic adhesives.

Does not hold up over time to direct exposure to UV light or chemicals

Susceptible to oxidation and may darken or discolor

Ideal for:

Seaming and flashing windows and doors

Repairing leaks

What Is Acrylic Tape, Exactly?

Acrylic tapes are either water- or solvent-based. They are created by crosslinking monomers to create polymers with specific properties. Acrylic adhesives are naturally tacky so they don&#;t require as many additives during the manufacturing process as rubber adhesives. Offering a good balance of adhesion, shear and tack, tapes with acrylic adhesive systems are resistant to thermal and UV degradation. They can be used on many surfaces and perform in a much wider application temperature range &#; typically anywhere from -30°F to 300°F.  The only real downside is the cost; these tapes cost a bit more than the rubber or asphaltic tapes. Builders often use acrylic tapes to completely seal a home, creating an airtight envelope.

When Are The Advantages to Acrylic Tapes?

Advantages:

Offers superior durability and longevity on polar surfaces (i.e. metal, glass, and polycarbonates)

Will not break down when exposed to extreme temperatures, UV light, chemicals or oxidation

Color stable and resistant to aging (will remain clear and not yellow)

Have a high level of cohesion (ability to stick to itself)

Are considered &#;greener&#; or more environmentally friendly in that do not off-gas or pollute landfills

Disadvantages:

Needs time (usually 24-72 hours) to fully set

Poor adhesion to low energy or non-polar surfaces

Impermeable to air only on polar surfaces

More expensive than butyl adhesives

Ideal for:

Seaming vapor barriers, house wraps, and rigid foam insulation

As always, the adhesive compound is just one factor that should be taken into account when selecting the right tape for the right application.  Characteristics like backing, strength, and permeability, as well as environmental conditions and substrate, are a few other factors that can impact the job, and ultimately, its success. 

Still not sure which type is right for your application? Contact us.  

If you want to learn more, please visit our website water seal aluminium rubber tape.