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 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 par quet. 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

water. Metal, synthetics, wood, paper, and textiles can be glued using dispersion adhesive. However, metal cannot be glued to metal in this way.

Misfits Cork tiles or rolls are also flexible floor coverings, but the glueing is done differently. Contact adhesive is used for cork and is applied on two sides. The adhesive bonding is achieved by spreading adhesive onto the substrates (surfaces) first. Once the solvents evaporate, an adhesive film forms which is almost dry. A solid bonding is created after a quick press on the contact surfaces. The materials are joined securely together at once, so sliding is no longer possible. Adhesives for non-permanent glueing are another misfit which we can mention for flexible flooring. Some adhesives allow for non-permanent glueing, and this means that the flooring can be removed without damaging the subfloor. That is the case, for instance, with a modified polymer-acrylate bonding.

Some specialists

Chimiver

ADESIVER RE 400/EXTRA Universal acrylic water-based adhesive with excellent permanent stickiness for vertical profiles and resilient linings laying on absorbent or semiabsorbent walls and subfloors. ADESIVER RE 400/EXTRA is a terpolymer acrylic water-based thixotropic adhesive characterized by high solid content, excellent spreadability and low water content. Suitable for indoor of: - carpet and needle punched textile with any backing provided they are dimensionally stable: - linoleum up to 3 mm thickness; - vinyl floors supported by felt; - PVC flooring in rolls or tiles; - textile floor coverings; - semi-rigid vinyl; - rubber sheets up to 3 mm thickness; - PVC flooring and coverings; - flooring and wall covering made by coco with back in latex; - styrofoam linings and styrofoam flooring.

ADESIVER RE 400/SP Universal acrylic water-based adhesive for vertical laying of profiles and resilient on absorbent or semi-absorbent walls and subfloors, with very long open time. ADESIVER RE 400/SP is a terpolymer acrylic water-based thixotropic adhesive characterized by high solid content, excellent spreadability and initial adhesion. ADESIVER RE 400/SP has an extended open-time recommended for the laying of stable resilient flooring provided they are dimensionally stable. Suitable for indoor of: - carpet and needle punched textile with any backing provided they are dimensionally stable; linoleum up to 3 mm thickness; vinyl floors supported by felt; PVC flooring in rolls or tiles; textile floor coverings; semi-rigid vinyl; rubber up to 3 mm thickness; PVC flooring and coverings; flooring and wall covering made by coco with back in latex; styrofoam linings and styrofoam flooring; LVT (luxury vinyl tiles) flooring.

Devo®

There are permanent and removable adhesives for LVT. The most commonly used compound is a polymer-acrylate bonding. Glueing LVT also makes no extra demands of an adhesive. Permanent dualcomponent adhesives have a similar base and do not differ much from parquet adhesives. Removable acrylate adhesives are not used for parquet. They don’t have enough tensile strength and cannot be combined with most primers. This is a completely different technology. Generally speaking, we can say that LVT adhesives differ mainly as regards viscosity. Their viscosity is much lower because they have to be applied in a thin layer, often using a roller or notched trowel. This is in contrast to a parquet glue where the standing time of the adhesive grooves is of crucial significance. Devo® Glue VNR150 spreads very easily and is usually applied with a roller. The floorboards are glued using a roller (for a removable fitting on a porous and smooth base). Floorboards are not fitted until the colour of the applied glue changes from milky-white to transparent (this takes 5 to 10 minutes).

Thomsit

Thomsit has a number of dispersion adhesives for the bonding of vinyl, linoleum, PVC and LVT floors. The latest adhesive in the Thomsit range is K 190 F, fiber reinforced PVC and rubber adhesive which is particularly suitable for PVC design with easy workability, short evaporation time and low consumption. Thomsit K 188 E is one of the top products in the range, a special high efficiency dispersion adhesive for wet and contact bonding of PVC floors in sheets and tiles, CV floors and rubber up to 2.5 mm thickness. The adhesive is unique in its kind due to the contact bonding that allows non-absorbent floors to be adhered to non-absorbent surfaces, such as PVC on PVC. Some PVC or LVT floors are also fixed instead of bonded so that elements can easily be replaced later. The roll fixation K 145 DesignTack is ideal for this and can be ergonomically applied with a roller. K 188 S is a very low emission dispersion adhesive with a very fast initial tack and good workability, excellent for LVT.