Frequently Asked Questions

This depends on several factors, such as the size of the gap and the bond area, as well as the coverage required. As a general rule, 1l of adhesive covers 1m2 at a thickness of 1mm. Keep in mind that more adhesive doesn’t always create a stronger bond. See this post on troubleshooting for more on this. For more information, please contact Permabond’s technical support team.

We usually recommend a bond line of between 100 and 200 microns, but this can vary depending on the bonding conditions. You can find the maximum gap fill for the adhesive you are using on its technical datasheet. This article provides more detail.

Permabond has a worldwide network of distributors who sell our engineer adhesive products. Please see our worldwide distributor locator or contact us for further information.

We manufacture a wide range of adhesive chemistries. These include cyanoacrylates, anaerobic adhesives, single and two-part epoxies, modified epoxies, MS polymers, structural acrylics, polyurethanes and UV-curables. Permabond also develops hybrid technologies, e.g. dual-cure UV-cyanoacrylates and UV-anaerobics.

This depends on the application. You will need to provide the following information to help us make a proper recommendation:

• What is the finished item?
• What are the substrate materials you wish to bond?
• What is the size of the bond area?
• What size gap do you need to fill, or are you looking for a coating?
• What are the environmental conditions (temperature/chemical exposure)?
• In what timeframe do you need the adhesive to cure?
• Is color important? If so, please state preference.

Contact Permabond’s technical support for further help with your application.

Here are various type of adhesive we do not currently manufacture:

• Solvent (including water) based adhesives
• Contact adhesives
• Silicone adhesives
• Tapes
• Single-part polyurethanes
• Adhesives that can withstand over 300°C

You can find a list of our most popular technical data sheets (TDSs) here. You can request a safety data sheet (SDS) by filling out this form. And of course, you can contact our world class technical support directly here!

Depending on the chemistry of the adhesive, the cured adhesive can withstand anywhere from -55°C to 230°C (in some cases even up to 300°C). We refer to this range as service temperature. Each adhesive’s TDS contains a Hot Strength chart that shows strength retention at various temperatures. Please be aware that at extreme temperatures/temperature fluctuations, adhesive properties can be affected in various ways.

Storage requirements depend on the adhesive in question. The ideal storage temperature can be found on the adhesive’s TDS. Here is a general storage guide by product type, but note that individual products or large package sizes may have different requirements. Please be aware that incorrectly storing an adhesive can significantly affect its performance!

We sell guns for dispensing from 50ml and 400ml cartridges only. If you require other types of dispensing equipment, we can put you in contact with the relevant companies.

Each cartridge comes with one mixing nozzle. If you require additional nozzles, please get in touch.

Viscosity refers to a liquid’s resistance to flow, or, put more simply, how ‘thick’ a liquid is. Viscosity is measured in millipascal seconds (mPa.s) or centipoise (cP). No conversion between the two units is needed as the number remains the same with both. The higher the number, the thicker the liquid and the greater its resistance to flow. Here are a few examples; Acetone is 0.3 cP (0.3 mPa.s), water is 1 mPa.s. Cooking oils are thicker at around 1,000 mPa.s, whereas peanut butter is highly viscous at 500,000 mPa.s – you could turn an open jar of peanut butter upside down and none would flow out! Different adhesives have different viscosities, with higher and lower viscosities being better suited to certain applications.

Some liquids are highly viscous (don’t flow easily) when stood still. However, when shaken, stirred or otherwise ‘brought to life’ in some way, they become more viscous and thus flow more easily. These liquids are known as thixotropic. Tomato ketchup and other sauces are great examples of thixotropic liquids – you often need to shake the bottle vigorously first to get them to move out onto your plate, otherwise they get stuck! Some adhesives are like this, too – highly viscous when still, but when agitated in some way, begin to flow more easily.

It depends on the adhesive in questions. Typically, it is somewhere between 365 and 400 nanometres. Please check the technical datasheet or contact Technical Support.

In addition to offering great-quality products, at Permabond we set ourselves apart from the competition with our outstanding level of support to our customers. We pride ourselves on being responsive and answering enquiries quickly, helping you to fully resolve any questions you may have. Not only this, but we are also open to making custom formulations for our customers if the desired volumes are right. This puts us in a unique position to deliver top-notch solutions to our customers’ bonding challenges, as well as drive innovation in the adhesives market.

Not necessarily. We’ve seen many applications where the Tg is significantly lower than the maximum operating temperature, however this very much depends on the application and the adhesive being used. For more information see this article on Tg or contact technical support.

CE Markings are only required throughout Europe if there is a European directive pertaining to the product. To date, there is no related European directive surrounding chemicals (including adhesives). Therefore, no CE marking appears on labelling or packaging.
However, many finished goods available in the EU contain chemicals or adhesives which may then be subject to an EU directive (such as the Toy Safety Directive, Medical Device Directive, Machinery Directive etc). Permabond products can be used on applications where the finished item needs to meet an EU directive. The adhesives have been produced in a carefully controlled, ISO9001 environment with commitments to meet both RoHS and REACH requirements and are suitable for the bonding and sealing requirements of manufacturers looking to meet CE directive requirements for their finished product assembly.

EU MDR relates to medical devices e.g. an actual item such as a catheter, tube set, breathing mask etc. not a liquid adhesive. Consequently, Permabond cannot claim that its products are meeting this regulation. Our adhesives, especially our medical device bonding range, are successfully used on medical devices throughout Europe and the finished bonded assemblies are meeting the EU MDR requirements without issue. Permabond adhesives are produced in highly controlled, clean and ISO-approved factories with a range of grades tested in accordance with ISO10993 cytotoxicity testing standards.

At times, when inspecting part A of an epoxy resin stored in a jar, bottle, or container, it may
appear cloudy, turbid, grainy, or even solidified. This phenomenon is known as resin
crystallization, characterized by a phase change from a liquid resin to a solid state. Similar to
the freeze/thaw cycles of ice and water, crystallization of epoxy resins is reversible, with the
resin’s original properties remaining unchanged despite repeated cycles.

Signs of Crystallization

Crystallization manifests as cloudiness, free-floating crystals, crystal masses, or complete
solidification. Initially, the clear resin becomes foggy, cloudy, or hazy, and instead of being
smooth, starts to gain a grainy texture. White sedimentation may gradually accumulate,
typically starting from the bottom or sides of the container, eventually spreading throughout
its contents. Once fully solidified, crystallized epoxy resin can remain in this state indefinitely.

 

Causes of Crystallization

Crystallization can occur unpredictably and may affect different containers within the same
production batch to varying degrees. Factors contributing to crystallization include resin
purity, viscosity, additives, moisture content, and temperature history, such as exposure to
extreme cold or thermal cycling.

 

High Purity

Highly pure resins are more prone to crystallization compared to impure ones. Narrow
molecular weight distributions indicate high purity, while broader distributions suggest
impurities. The addition of anti-freeze or high molecular weight oligomers/isomers can hinder
crystallization but poses formulation challenges.

 

Low Viscosity

Lower viscosity resins, particularly when combined with reactive diluents, crystallize faster
than higher viscosity ones. Temperature reduction decreases molecular motion, slowing
crystallization. However, storing resin at 0°C may inadvertently promote crystallization due to
hidden seed crystals.

 

Additives – Solid Fillers

Solid fillers like precipitated calcium carbonate, alumina, silica, or even scratches on
container surfaces can act as seeds for crystal growth, accelerating crystallization.

 

Temperature and Thermal Cycles

Cold temperatures slow crystal formation by increasing viscosity, but extreme cold
accelerates growth once seed crystals form. Temperature fluctuations, even of as little as 20-
30°C, are a very common cause of crystallization, especially during day-night cycles.

 

Solutions

Crystallization tends to be more of an inconvenience than a real problem. Re-melting
crystals by heating resin to 50°C for several hours effectively reverses crystallization.
It’s crucial to ensure complete melting of all crystals, preventing them from acting as seeds,
before cooling to room temperature. Carefully inspect the container’s sides, bottom, and
areas around the caps for any signs of crystallization that could initiate further growth.
Whenever possible, it’s advisable to clean bottle caps, bottle necks, spigots, spouts, pumps,
piping, and valves with a solvent such as isopropyl alcohol (IPA) or acetone after each use to
prevent seed development. Monitoring and controlling shipping and storage temperatures
effectively prevent crystallization due to temperature fluctuations. Good housekeeping
practices also play a significant role in preventing crystallization.

Important Note: Re-melting of crystals should exclusively be performed on the resin side
(part A) of the epoxy. In rare instances, warming a part B or single-component system might
be necessary. Please consult our Technical Experts for specific heating recommendations.
It’s important to refrain from using this technique with pre-mixed and frozen systems, as it
could lead to premature curing or cross-linking.

 

To summarise in brief:
– Epoxy crystallisation is a common phenomenon
– It is easily reversed by heating resin at 50 deg. C for 2-3 hours
– Strength and performance properties of the adhesive should remain unchanged after
crystal re-melting process.