Special
The various adhesives and glueing techniques for LVT, PVC, vinyl, and design floors
FLEXIBLE FLOORING OPTS FOR DISPERSION ADHESIVE LOW VISCOSITY HELPS WITH THIN-FILM GLUEING
Photo – Thomsit
Adhesives for PVC, linoleum, and vinyl have to meet different requirements to those of wood adhesives. For instance, those floors have a smoother and more sealed structure than wood. This means they can hardly absorb the water in the glue, so semi-wet or quasi-dry glueing is necessary. Moreover, these materials swell and shrink a lot less than wood, so the elasticity requirements are different. The adhesive and the subfloors are put under much less strain (fewer sideways tensile forces) than with wooden floors. Nevertheless, the adhesive has to be strong enough to achieve durable bonding. Dispersion adhesives and some PU adhesives meet these requirements perfectly.
It all starts with the base The thinner a floor covering is, the more any unevenness in the base shows up on the ‘visible’ side. Obviously, the combination of thin and flexible only serves to increase that effect. If we put a sheet of silk paper onto a table full of crumbs, every crumb is visible. The same test with a piece of solid cardboard yields a completely different result. All this means that glueing flexible flooring requires a lot of preparatory efforts to make the base suitable. By suitable we mean ‘perfectly level’ and free of any remains of dust and dirt. In many cases prior levelling will be essential for glueing LVT, PVC, linoleum, or cork. In equally as many cases the nature or ‘health condition’ of the screed will still require a primer first before the levelling agent is used.
Then comes the adhesive It is clear that if you set very demanding rules for the evenness of the base, you apply them also to the type of adhesive and, in particular, to the nature of the set adhesive. A sturdy adhesive groove, which we admire in lots of floor coverings such as parquet, is not really
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desirable for flexible flooring. It should be possible to spread an adhesive equally without too much difference in thickness and the adhesive should set evenly. For glueing vinyl and lots of other flexible floor coverings we prefer to use a dispersion adhesive, which works on the basis of a physical adhesive bonding.
Physical adhesive bonding We’ve outlined this adequately in the past. Adhesive bondings can be created from a physical or chemical reaction between different components. It is clear that the wood sort plays a part in glueing parquet. That is no less the case for glueing flexible flooring. Damp and oxygen almost always play a part in the glueing process. No chemical reaction occurs with adhesives which work on the basis of a physical reaction. Various mechanisms are possible. For example, an adhesive reaction can occur as a result of the loss of solvent. This occurs via evaporation. Usually, the solvent evaporates for a certain time before the parts to be glued are secured. Another physical adhesive reaction occurs by means of cooling. The adhesive mass is applied as hot fluid to the surface to be glued. The adhesion to the second material to be glued takes place by means of cooling.
Dispersion adhesives Dispersion adhesives belong to the category of glues which enter into a physical adhesive bonding. With these adhesives, a synthetic resin such as polyvinyl acetate, acrylate, or polyurethane dissolves in water. An organic solvent is added for some applications. Emulsifying agents, cross-linkers, and preservatives can be found in the adhesive in some sectors. Dispersion adhesives set through the extraction of the water from the glue to create an adhesive film (water disappears, solid substances remain, and the bonding is created). This means that one of the parts to be glued must be capable of absorbing
