Recently, I was reviewing the keyword search terms people used to reach our website. The following is just a sampling of the searches that came up most frequently:
- “Most powerful double sided tape”
- “Strongest double sided tape”
- ‘Super strong double sided tape”
- “Strongest double sided tape for glass”
- Strongest double sided tape for walls”
- “Best double sided tape”
- “Super strong sticky tape”
Defining a Double Coated (Sided) Tape
A double coated or double sided tape is a specific tape format where a pressure-sensitive adhesive is coated onto both sides of a carrier or in some cases with acrylic foams — a foaming agent can be incorporated into an adhesive matrix and then” foamed” so the resulting tape is monolithic but in fact, has adhesive on both sides. A release liner can be applied to both sides of the tape or more often a double siliconized liner is used that allows the tape to be wound on itself (also referred to as self-wound).
(Photo Courtesy of 3M)
Types of Carriers and Impact
Carriers or backings are an important element of the double coated tape because they have a significant influence on the physical properties and the ultimate performance of the tape. These properties impact the selection of the best tapes for a given application.Contributions of Carriers
- Flexibility
- UV resistance
- Thickness and density
- Tensile strength
- Elongation
- Moisture resistance
- Abrasion resistance
- Electrical/ and thermal conductivity or insulation
- Color
- Transparency
- Flame Retardance
Common Foam Carriers
Acrylic Polyethylene Polyurethane PVC (polyvinyl chloride)Common Film Carriers
Polyester Polypropylene UPVC (unplasticized polyvinyl chloride)Other Carriers
Tissue Paper Nonwovens
Matching Tape and Application: Questions to Narrow the Field
Ask the following questions to decide which tape will work best for your situation.- What is the end-use and what are you trying to accomplish? You should be able to answer this in one sentence most of the time.
- What materials are you bonding? There is no “one tape fits all” with double coated tapes. You have to identify what you want to bond together so you pick the best candidates. Different classes of materials act very differently.
- Are there any gaps to fill? The tape must have the right gap-filling ability for any uneven or non-planar surfaces.
- What stresses or loads will be present in the application? The forces can include shear, tensile, cleavage, and peel. If you can identify these forces, you can choose a tape that will maximize your chances for success.
- Is the bonding surface rough or smooth? Rough surfaces usually require tapes with higher adhesive coat weights or thicknesses to allow the adhesive to flow into surface irregularities and provide better wet out. Better wet out will yield higher bond strengths.
- What are the application temperature and service temperature? What are the conditions where the tape is applied and what high or low temperatures will be encountered during service life? Some tapes work exceptionally well at low temperatures and others have excellent high-temperature performance.
- Will there be any exposure to UV light, chemicals, or moisture? These factors along with temperature and the various forces outlined in question 4 will create the operating environment for the tape.
“Go-To” Product Recommendations
In the introduction, I stated that it is impossible to pick only one “strongest double coated tape” due to the high degree of variability and performance requirements encountered in each application. There are, however (in my opinion) a group of “best in class” or “go-to” tapes that are a great starting point for many applications. Here they are:Double Coated Foam Tapes
Acrylic Foam Tapes
- 3M VHB – the VHB portfolio contains almost 100 products and they are all excellent!
- Saint Gobain Norbond® Acrylic Foams – especially the new A7600
Double Coated Polyethylene Foam Tapes
- Adhesives Research – 2000 and 4000 Series
- Berry Plastics – GTW / GTB Series
- Adhesives Applications- 7016B, 65016B, and 7316B
- Mactac – IM1863
Double Coated Film Tapes
This section is broken down by surface energy classification since there are more double coated film tapes than any other type.Double Coated Film Tapes for HSE (high surface energy metals and plastics)
- 3M 92015
Double Coated Film Tapes for Foam Bonding and Rough Surfaces
- 3M 9832
- Berry Plastics 350 Series
Double Coated Film Tapes for LSE (low surface energy plastics and paints)
- 3M 93015LE
- Berry Plastics 650 Series
Engineers spend endless hours developing new products and revising current designs to meet market demand. The timelines are demanding, which can make it feel like there are never enough hours in the day.
It’s understandable that tapes (and die cut parts made from tape products) are not always at the top of the to do list. Yet these products can be critical in the bonding and assembly process or for sealing and gasketing applications to maintain product integrity.
Fortunately, tape converters are well positioned with a unique set of “tools” that can produce solutions to save both time and money.
Material Portfolio and Selection
Converters know and source products from a variety of the most reputable tape and raw material manufacturers. Each manufacturer offers certain product lines that are “best in class” in terms of performance and cost. Having a broad product portfolio brings maximum problem solving capabilities to almost any project. However, a broad product portfolio is nothing if it can’t be applied effectively. Invest time answering key questions with a converter will shorten the path to a solution. These key questions will typically involve looking at the surface, environment, joint stresses and the product application. Questions to ask include:- Surface –What is the type of surface, surface energy, geometry, texture, and preparation?
- Environment –What are the chemicals the tape or die cut part will encounter? What is the UV exposure and the high/low temperatures?
- Joint Stresses –What are the physical forces that will be acting on the bond line during service?
- Tape or Part Application –How will the tape or die cut part be applied?
Rapid Prototypes
Competent converters have equipment and processes that allow prototypes to be prepared quickly. This can be as simple as slitting rolls for evaluation or by utilizing “digital die cutting” methods such as waterjet, flash knife, or laser to produce precision parts; often within 24 hours. When you combine the material selection screening questions with the rapid prototyping capabilities, the evaluation and qualification process can start immediately. Any additional tweaks or changes can be usually be incorporated rapidly and new prototypes presented.Deployment
While the final evaluations are in process, it’s time to consider effective deployment of the tape or die cut part. If the solution requires rolls of tape, decisions on how the tape will be applied need to be considered. In many cases, tape is hand applied and there is nothing wrong with this approach. In other cases, a hand held, tabletop, or semi automatic dispenser might be much better suited for certain manufacturing situations. The converter should have the right connections to help with these requests. Die cut parts can have even more options. The parts can be cut through into discrete parts, kiss cut on a roll, or have tabs and extended liners. While removing a liner from a discrete part is fairly simple, it may take an extra second or two to do this instead of removing a kiss cut part or utilizing an extended liner. A second or two doesn’t seem like much. However, when you add up thousands of seconds over a year, the savings can usually be measured in days or weeks.How Can We Help?
Tom Brown, Inc. is a full service converter with a unique set of tools that can be rapidly deployed to help customers solve product development challenges; especially those that happen under time pressure. Our broad product portfolio, material selection experience, rapid prototyping capabilities, and process engineering knowledge can significantly reduce product development time when solving bonding, assembly, gasketing, and sealing challenges. Contact us to discuss your project. www.tombrowninc.com
One of the first questions anyone in the tape industry asks is “What surface(s) are you trying to bond or stick to?”
This screening question provides some initial clues into how challenging it might be to adhere to the surface. It also provides insight into what tapes or adhesive systems might be best suited for the application.
Aside from questions on chemical and temperature resistance, they might also ask about surface energy, roughness or texture.
Let’s look into these questions and why those in the tape industry ask them.
Surface Energy
The standard definition of surface energy is “the excess energy at the surface of a material compared to the bulk.” This “excess energy” exists because the molecules at the surface are not surrounded on all sides by other molecules.
Surfaces that have a predominance of carbon-hydrogen bonds tend to have low surface energy (LSE) and do not wet easily. For example, you can see this with a freshly waxed car like in the photo above and also with plastics such as polyethylene and polypropylene.
Surfaces that contain oxygen-carbon bonds, nitrogen or other halogens tend to exhibit higher surface energies and better adhesion properties.
The unit used to measure surface energy (for solids) and surface tension (for liquids) is dyne/cm—or more commonly “dynes.” Metals, such as aluminum (850 dynes) and stainless steel (700-1100 dynes), exhibit high surface energies and are easy to adhere to for almost any adhesive.
Bonding starts to become a bit more challenging when you get to EVA at 33 dynes, polyethylene at 31 dynes and powder coat paints in the 23-27 dyne range.
Adhesive Selection
Rubber based adhesive tapes will develop good adhesion to most surfaces down to about 30 dyne/cm. This wide adhesion range is great from an adhesion standpoint. However, if the application requires UV resistance, chemical resistance or high temperature resistance, many rubber-based systems will not perform well.
Acrylic adhesive tapes don’t have the same limitations with UV, chemical or temperature resistance that the rubber-based adhesives do. But these acrylic adhesive tapes do have a narrower adhesion range. Selecting the best candidates require a little more care. For ease of understanding, acrylics can be classified into three broad groups: pure acrylics, modified acrylics and LSE acrylics.
Pure acrylics (no modifiers) are good choices for bonding to metals, glass and other surfaces down to about the mid 40 dyne level. Modified acrylics have added tackifiers that extend the adhesion range down to the upper to mid 30 dyne level. LSE acrylics can even go a bit lower.
Surface Roughness
The unaided human eye can resolve objects down to roughly 100 microns (0.1mm). Surfaces that look and feel smooth can have very interesting surface features when viewed under magnification. For example, look at the stainless steel images below.
Surface textures such as embossing, stippling and coatings add aesthetic beauty and functionality such as anti-slip, stain resistance and a host of other benefits. The topography of these textures must be accounted for when selecting the best tapes.
The pressure sensitive adhesives on tapes behave like both a solid and a liquid. This property is called viscoelastic behavior. The diagram above shows the benefit of selecting the appropriate adhesive thickness to maximize the “flow” of the adhesive into the valleys of the surface topography that will maximize bond strength.
For most industrial bonding applications, tape manufacturers typically offer tapes with adhesive thicknesses in the 1 mil (25 microns) to 5 mil (125 micron) range that will handle the majority of metal, glass and plastic bonding. Duct tapes and other specialty products contain even thicker adhesive coatings to handle porous surfaces such as concrete.
Summary
Tapes bond to surfaces without changing the inherent characteristics of that surface. The molecular force of attraction along with some mechanical interlocking determine ultimate adhesion. Also, the strength of that attraction serves as a function of understanding surface energy.
Often the first question asked by those in the tape business center around understanding the surface(s) involved in bonding. The surface chemical structure along with any information on coatings, treatments and texture provide additional insight into selecting the best tape for the application.
Have a question about tape bonding? Contact Tom Brown, Inc. today!
What is a Durometer and How Does it Affect Which Materials You Select?
A durometer is an instrument for measuring the hardness of a material; typically plastics, rubbers, and other elastomers. The test involves bringing a probe or foot into contact with the material at a specified rate, load, and time and the values are reported on a scale. (more…)
Many of you have probably used duct tape or masking tape during the winter months and might have noticed that it doesn’t seem quite as “sticky” as it normally does. This reduction in tack or “stickiness” is normal and will become more noticeable as the temperature drops below 40°F. Let’s explore why this happens. (more…)
When you’ve been in any type of business for a long time, you sometimes realize how much you take for granted or assume that other people know or understand. That hit me the other day when I was reviewing tape technical data sheets from two different manufacturers and realized that the data listed might not be easily understood by someone who isn’t in the tape business. Here are some of the common test methods and data listed in many tape technical data sheets and some guidance on how to apply that information to your application. (more…) It’s very difficult for most people to visualize how a tape could possibly replace a rivet, screw, or other fastener. After all, mechanical fasteners are made of metal and there’s no way tape is as strong as metal, right? Well, not exactly. If you just examine the fastener itself and compare it to acrylic foam tapes, you might think this is the case, but you would be mistaken. The strength of the fastener itself is not indicative of the durability or strength of the final bond. The physics are a little more complicated. (more…)When selecting foam substrates for end use applications, there are a number of factors to consider such as thickness required for gap filling, density, chemical resistance, UV resistance, and temperature. Another important consideration is whether open cell or closed cell foams are the best choice.
Cell Foam Definitions
In open cell foams, the gas pockets that form during the manufacturing process are connected to one another creating an interconnected pathway. Closed cell foams have gas pockets or cells that are closed or sealed off from the neighboring cells preventing absorption of liquids or gases.
Which Cell Foams to Choose?
Open cell foams are very pliable and typically softer to the touch. They are the best choice for applications requiring airflow such as speakers, compressors, HVAC, and face mask applications. They are also excellent choices for applications requiring cushioning in packaging applications where you need to absorb the shock experienced during transport. Open cell foam also absorbs sound waves and can reduce the noise generated by equipment and small appliances.
Open Cell Foam Capabilities
- Sound wave absorption
- Dust filtering
- Manage outgassing in adjacent materials
- Allows adjacent materials to cure (sealants for example)
- Holds or wicks liquids
- Low pressure gaskets for dust, light, and vapors
Closed cells typically have higher densities and tend to be more rigid. Liquids and gasses do not have any open pathways since each cell is separated from its’ neighboring cells.
There is a large palette of chemistries for closed cell foams. They include PVC, polyethylene, neoprene, EPDM, polyurethane, silicone, and a variety of blends.
Closed Cell Foam Capabilities
- Medium and high pressure seals for liquids, air, and dust
- Die cut gaskets
- Excellent shock absorption
- Sound insulation
- Good compression set and compression/deflection properties
Want to learn more about open and closed cell foams or need a sample for evaluation? Contact Tom Brown, Inc. today!
Unique materials can be created through the use of lamination techniques and equipment. Properties such as fire resistance, sound and vibration damping, improved tensile strength, adhesion, and cushioning can be tailored to meet the needs of your particular application. Understanding adhesive laminations is a core competency at Tom Brown, Inc. to help you achieve the results you want. (more…)