Parquet adhesive

For the purpose of the swelling behavior, sensitive parquet formats with bright decoration, such as beech and maple, require the development of both water- and solvent-fi-ee reactive resin flooring adhesives. In addition to epoxy, resin adhesives used in Germany are mainly polyurethane adhesives. The environment-friendly way to glue flooring is undoubtedly the use of water-based dispersion parquet adhesives. These consist of polyvinyl acetate polymer dispersions and binders such as chalk and mineral fillers. 

Amino resins are manufactured throughout the industrialized world to provide a wide variety of useful products. Adhesives (qv), representing the largest single market, are used to make plywood, chipboard, and sawdust board. Other types are used to make laminated wood beams, parquet flooring, and for furniture assembly (see Wood-BASED composites and laminates). 

From 1 January 2000, Dutch law prohibits the use by professional carpet fitters of solvent-based adhesives. The Organic Psycho Syndrome law concerns the adhering of coverings to floors, stairs, walls and ceilings in houses and any other buildings. Key issue in the OPS law is that professional users are no longer allowed to use products containing more than 0.5% solvents. The law also affects painters and parquet installers. 

Heudorf U, Angerer J. 1999. Urinary levels of 1-hydroxypyrene, 1,2,3, and 4-hydroxyphenanthrene in children living in residences with high PAH-contents of adhesive used for parquet floors - additional information. Umweltmed Forsch Prax 4(2) 97-100. 

Highly Reactive Adhesive Resins in Plywood, Parquet Flooring, and Door Production... 

Plywood, parquet flooring, and doors are usually produced using aminoplastic adhesives. The press time necessary for these applications depends on the press temperature, the total thickness of the wood layers which have to be heated through, and the reactivity of the resin glue mix. Traditional adhesive resin systems need rather long press times due to their... 

Solvent-based adhesives (commonly used on laminates, tiles, parquet and vinyl flooring) can contain alcohols, ketones, hydrocarbons, plasticisers, and some monomers. 

Uses Epoxy-actylic tor UV- and EB-cured coatings (wood, metal, plastic), inks (screen, litho), laminating adhesives, overprint varnishes, parquet flooring... 

Chem. Descrip. Self-crosslinking elastomeric silicone aq. emulsion Uses Adhesion promoter, flexibilizer, water resist, aid, detergent resist, aid in printing inks water repellent, water resist, aid in industrial coatings, parquet varnishes, facade paints, wood coatings, plastic coatings, leather coatings, aq. systems, esp. acrylic disps. 

EPI, Emulsion Polymer Isocyanate, MDI, pMDI, wood adhesives, solid wood panel, parquet, window frame, furniture, plywood, finger joint, glulam beam, I-betim, cross-laminated timber... 

In Europe the most common types of wood based flooring are two- and three-layer sandwich parquet. In these constructions a decorative surface layer is glued perpendicular to a core consisting of pine- or spruce-ribs or different board materials. Veneer is used as backing material for the three-layer construction to stabilize the construction (Fig. 8). Two-layer parquet is mainly produced with PVAc. Three-layer sandwich parquet is produced with both UF adhesives and PVAc adhesives, but the use of UF adhesives is predominant. 

Currently the volume of EPI adhesives used for the production of parquet in Europe is very low. The volume is expected to increase as the demand for parquet produced with non-formaldehyde adhesives increases. Due to their high moisture-and heat-resistance EPI adhesives give more robust parquet than PVAc adhesives, especially if the parquet is used with floor heating. 

SikaBond -66 AT is a universal assembly adhesive for construction as it is a phthalate-free PUR-Hybrid adhesive with good bonding and compatibility to polystyrene insulation. An application is described in Section 6.8.8 entitled Bonding of Parquet/Timber Floors . Its mechanical properties are summarised in Fig. 82, along with those of Sikaflex -20. 

The volume changes due to swelling and shrinking are accompanied by movement, which causes considerable shear stress in the adhesive layer and the substrate. The adhesive must follow the swelling of the wood reliably and in such a way that the wood not only remains undamaged but that a shear-resistant bond is formed between the parquet floor and the substrate. 

Fig. 101 compares adhesives as per DIN 281 with low-modulus elastic parquet floor adhesives for their tensile shear strength and elongation. 

Figure 101 Position of parquet/timber floor adhesives in the stress-strain diagram.

An even distribution of stress in the bonded adhesive area is necessary to ensure a durable bond and to take full advantage of the material properties. Conventional rigid bonding, however, causes stress peaks at the edges of parquet boards. Elastic adhesives, on the other hand, transmit forces over the whole bonding surface. 

These adhesives are therefore particularly suitable for large-surface bonding applications such as parquet floor laying. The high shear forces are absorbed and at the same time the substrate is not exposed to undue risk of damage. Theory shows that low-modulus elastic adhesives can ensure a shear-resistant bond of the parquet flooring to the substrate. 

Figure 102 Test performed under extreme conditions to illustrate the performance of elastic adhesives for parquet/timber flooring Left adhesive as per DIN Right elastic adhesive.

Both tests simulate ageing behaviour under extreme conditions. This does not mean that parquet floors bonded with rigid adhesives will necessarily show this joint gap pattern. Both tests, however, highlight the improvements that can be achieved by the use of elastic adhesives for bonding parquet floorings. 

Figure 103 Influence of adhesive type on gap width in parquet/timber floors (extreme test conditions) Left synthetic resin adhesive Right elastic adhesive.

Wood Floors. Wood floors probably were first installed in the mid-11th Centuiy, and have been a leading flooring material ever since. Today both hardwoods such as oak, birch, beech, and maple, and softwoods such as pine and fir are used for wood flooring. A number of different types of wood floors are installed with adhesives among these are solid block parquet, laminated parquet, solid finger block, strip, and plank-type flooring. 

It is not uncommon to find flooring materials used as wall covering, for example, wood parquet flooring and carpeting. They require different adhesives from those used on floor installations, with sufficient green strength to hold the flooring material in a vertical position. 

Some reactive polyurethane adhesives such as one- and two-component ones are particularly suitable for wood bonding. They are currently being used for the bonding of parquets and other wood flooring, mainly because of their strength and resistance. They are also being used for bonding of heavy duty rubber floor in commercial areas with heavy foot traffic [24]. 

Floors of any type are placed almost exclusively by bonding technology. Therefore, solvent contact adhesives, dispersion adhesives, and pressure-sensitive adhesives are widely used for this application. For bonding parquet, the following types of adhesives are mainly used... 

Solvent-based synthetic resin flooring adhesives are still the most used floor adhesives and possess a dominant market position, despite the best efforts of the building professional society, which tried to reject them, because of their excellent processing characteristics. It is estimated that its market share is about 65-70%. They are made from solvent mixtures (such as methyl acetate, acetone, ethanol, and methanol), dissolved synthetic resins (polyvinyl acetate), and mineral fillers such as chalk. The solvent content is between 20% and 25%. Solvent-based synthetic resin flooring adhesives contain no water and, therefore, cause a relative slight swelling of the wood parquet. 

With elastic polyurethane adhesives, almost all construction materials are laminated together, such as concrete, wood, ceramics, plastic, and metal. Thus, completely new design possibilities arise. When bonding steps, parquet, or tiles, two advantages come into play, namely, the impact sound insulation and the background-balancing property of the adhesive (Brunner 1996). 

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