2020/02 The evolution of Union Foam’s CNX Adhesive Range

Union Foam has chosen to simplify and rationalise the CNX Adhesive range to respond both to the more demanding Health & Safety standards in this sector and to react to evolving market requirements for ease of installation particularly when it comes to the use of High Temperature Adhesives. The solutions we are offering with the Union Foam range are as follows:

CNX S will replace CNX Adhesive for all standard applications
CNX AT1, is a one-component adhesive specifically developed for higher temperature applications up to 150 °C; it replaces CNX AT, which had to be mixed with a hardener before use.

Both CNX S and CNX AT1 are solvent based neoprene adhesives. CNX S differs from the previous adhesive in terms of use it has longer open time, the viscosity has changed and it has a more transparent colour.

The “open time” and “tack time” of an adhesive are important parameters when it comes to making a good adhesive joint. The time from when you start applying adhesive to when you bring the two adhesive coated surfaces together is known as the Open Time. The Tack Time is the time it takes for the adhesive to have dried sufficiently for one to be able to bring the two surfaces together, the adhesive is dry to the touch but tacky under pressure, you test this with your nail not with your finger. There is a time interval between the Tack Time and the Open Time when a contact adhesive is able to form a satisfactory bond between the two surfaces to be bonded.
With CNX S Adhesive the Open Time as compared to the original CNX Adhesive has been extended whilst the Tack Time remains the same, this means that there is now a longer time interval during which surfaces can form a satisfactory bond; this is a useful benefit when trying to bond larger surface areas together.
A further advantage of the new CNX S formulation is that it is more transparent in both its wet and dry states, this means the once the solvent has evaporated any residual adhesive on the surfaces of the insulation is less apparent and this leads to a more aesthetically pleasing appearance.
Finally the viscosity of the product has been reduced: the adhesive is slightly more fluid so that it can be applied more quickly and more easily and the result is more likely to be a thin and even film. If a second layer of adhesive needs to be applied because the Open Time has been exceeded then this should be achieved without the adhesive ‘stringing’.

CNX S has a low Volatile Organic Content (VOC). Pan European regulations regarding VOC emissions of this type of product are not in force yet. However there is a French regulation for Building Materials which offers a clear classification of adhesive products according to their level of volatile substance emissions, the scale goes from A+ (minimum scale) to C. Union Foam has decided comply with this regulation and apply it to the standard adhesive it sells across Europe; CNX S fully achieved a classification A+.

Union Foam’s adhesives are available in tins of the following sizes; 200g (0.25l), 425g (0.5l) and 850g (1l).
As CNX S is a solvent based adhesive it should be exposed to air for the minimum possible time to minimise solvent evaporation. For this reason we would recommend that where large lever lid tins are supplied a smaller quantity of adhesive, sufficient for the immediate requirement, is poured in to a secondary container before use and the original container is then kept tightly sealed.

Union Foam has sent an early application to obtain the UFI CODE No. (Unique Formula Identifier) of their new adhesives, in advance of the legal deadlines to display this code in various markets.
A 16 -digit code will be shown on the label of the relevant product and this will make the communication with the Health & Safety Executive or other relevant organisations more effective, allowing if necessary the supply of all necessary information in the case of intoxication.