Posted by Martin Cummins on
You’ve got to roll with it
The bonding of cap and coving and skirting profiles has traditionally been achieved using contact adhesives. Indeed, most experienced contractors will reference the unmistakeable smell from solvented contact adhesives as one of their abiding memories when coming up through the ranks.
This remained the case for many years because, the truth is, contact adhesives worked and enabled fitters to install the tricky vertical components required for such installations. The benefits offered by solvent based contact adhesives were that the adhesive dried relatively quickly on both surfaces and they created an instant bond when putting the materials together.
Alternative contact adhesives using water rather than solvent as the carrier were brought onto the market some 15 plus years ago but never really caught the imagination of the installers. The main reason for this was that water takes a while to evaporate, so the time spent standing around waiting for something to happen was a big problem. As manufacturers we of course encouraged these safer alternatives for the health and safety benefits to the end user, but I think we were all well aware of the limitations. You needed a warm environment and a clean, uncluttered area to roll out the products for an hour or two to let the adhesives dry. These ideal conditions are not what we see a lot of in our industry, so solvent based contacts remained the default… until now.
In addition to the health and safety and flammability issues with solvents, which of course everybody should be looking to negate if possible, there are also other issues pertaining to the installations themselves when using solvented contact adhesives. These include the potential for discoloration and for plasticiser migration.
Residual solvent, even at tiny amounts can leach plasticiser out of flexible profiles and result in shrinkage as they stiffen up. Furthermore, when bonding the vinyl flooring to the cap and cove, it has been observed on many occasions that with heterogeneous (layered products) there is a significant chance of discoloration (generally yellowing) of the upper layers. After many discussions with vinyl manufacturers and our own in-house research, it was deemed that the risk both from performance and duty of care for the installers meant an alternative approach was needed.
The answer has been to develop Bostik Roll – a robust, high bond, plasticiser resistant, pressure sensitive tape. The manner in which this works is radical in comparison to contact adhesives, in that you don’t apply the product to both surfaces. There is a release film on the tape which is removed to enable the pressure sensitive, dry stick adhesive to be rolled up the clean, dry, dust free wall, or where appropriate onto the coving itself. By applying consistent pressure, the adhesive bonds very securely to the substrate, leaving another release film presented to the contractor. When ready to bond the profile, (or floor covering), this release film is removed to reveal the high strength pressure sensitive adhesive. By careful placement and again applying a consistent overall pressure, a very strong bond will be achieved.
The benefits of this approach are numerous, with Bostik Roll offering all of the following:
• No smelly solvents
• No discoloration
• Plasticiser resistance
• Instant bond – so no waiting around
• No need to clean up or throw away brushes/tools
• No waste other than the release film which is a non-hazardous material suitable for general disposal
• Various sizes to suit specific applications
• Clean hands at the end of the day
All the contractor needs to do is open his mind and rethink the process. At the moment of writing I can confidently say that of the installers who have tried the product, only one has reported negative feedback. This was because of the need to ensure a clean, dust free surface which he perceived as being an additional process. This is a fair comment, but in all honesty every contact adhesive manufacturer would state that it should only be applied to a clean, dust free surface.
The only failure I have seen is where a contractor used a solvent based contact on the top edges of the skirtings and tape for the rest. The solvents basically softened the pressure sensitive adhesive and plasticised the skirting, resulting in it bubbling away. Asked why he did this, he said he wasn’t sure how good the tapes worked so wanted added security from the adhesives. Don’t mix and match!
Key points to ensure performance, other than a clean, dry, dust free surface are as follows:
• Always apply to the substrate rather than onto the back of the profile or the floor covering
• Check if any existing materials on the substrate are still suitable for bonding onto
• Don’t prime with a contact adhesive first… especially solvented or spray adhesives as these will cause debonding and plasticiser issues
• Don’t remove the release film until ready to bond the materials so as to keep from dust contamination
• Get reasonable working temperatures, otherwise you will be minimising the bonding capability of the pressure sensitive adhesives and also potentially introducing a moist surface, which will again reduce bond strength
So, let’s ‘roll with it’ and move into the 21st century. It’ll be good for you, good for the flooring products and good for the environment…what’s not to like?