Surface Energy - the little thing that can solve your big problems
What is Surface Energy?
Unbeknown to many of us, a little thing called 'Surface Energy' could be affecting the way you use and get results from an adhesive. Whether you want your adhesive to create a permanent fix or to peel off easily like a Post-it note, Surface energy will affect just what type of bond you will end up getting.
So what is Surface Energy you ask? Surface Energy, also known as surface tension, is determined by the composition and arrangement of molecules within a material. For instance, the difference between water and oil: two liquids however, that just don't mix. Water has a high surface energy and will form distinct droplets, whereas low surface energy oils, spread out or 'wets out' on most surfaces, making oil an ideal lubricant. Oil derived plastics also have a low surface energy characteristic and it is a major achievement of the adhesive technologists to have developed products to work effectively within them.
Another science-y fact: surface energies are also determined by polarity. For instance, water's asymmetric molecule will create a higher charge than the symmetric molecule of oil-derived polyethylene. This charge of polarity gives water a high surface energy. Low surface energies are sometimes called 'apolar materials'
In order to form a bond, an adhesive needs to 'wet out' on a surface. If adhering to a high surface energy the tape will wet out easily, however this is the opposite with low surface energy substrates
Obviously if you have a high surface energy substrate, your pick of adhesive is a lot easier, however lower surface energy materials can also offer benefits too: whilst it's obviously difficult for adhesives to bond to these type of surfaces, it is also very difficult for dirt and contaminants to stick to them. These characteristics are used to good effect with easy to clean and self-cleaning surfaces as well as anti-graffiti finishes.
Low surface energy materials are also often very cost-effective and can also have rather useful chemical and physical properties - for example:
- Polypropylene has excellent resistance to flexing, and is economical, solvent resistance and easily moulded and extruded.
- EPDM rubber is excellent for weathering as well as for resistance to Ozone and some solvents
- Powder coated paints are tough, economical, and contain no hazardous solvents.
As you can see, these lower surface energy materials are proving more and more popular, and are being increasingly used in all sectors of manufacture; this is why here at Technibond, we are working hard to provide a complete range of adhesive tapes to deal with all specific surface energy demands.
Our surface energy chart, available if you click here, will help categorize the adhesive type needed for different materials. If you are still struggling with your surface, you can send us a sample and we will quickly test it in our lab and advise you of the surface energy and an adhesive type to match. Phone us to arrange this on 01628 642800.
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