Adhesives for Wallcoverings

Wallcoverings, classified by EN 233-235 [133], consist of a variety of materials: paper, textiles, glass, plastics (PVC, PE, PS, PU), ceramics, wood, cork, metals, leather. They are attached by hand in the form of sheets (wallpapers), tiles, or profiles to masonry, plaster, concrete, plasterboard and gypsum wallboard, wood, and metals.

For ease in do-it-yourself projects (adjustability, open time, easy application, etc.) and because most substrates to which the coverings are bonded are capable of absorbing moisture, it is preferable to use water-based adhesives in the form of solutions and emulsions. Solvent-containing adhesives are only used on nonporous substrates, for example, metals [86], [87].

The adhesives are based on methyl cellulose, starch ethers, carboxymethyl cellulose, pre-gelatinized starch, poly(vinyl acetate), polyacrylate, styrene — butadiene latices, polychlorobutadiene, and polyurethanes. The viscosity of the adhesives covers the range from fluid to pasty.

Wallpapers include those with a PVC or metal surface and rough-textured plain wallpapers. They are applied with pastes of pre-gelatinized starch, starch ethers, carboxymethyl or methyl cellulose in the form of 2 -10 % solutions. For rough-textured plain wallpapers and heavy wallpapers, moisture resistance and tack are increased by utilizing poly(vinyl acetate) redispersion powders. High solid, emulsion-based adhe­sives, optionally in conjunction with resin-enhanced pastes (special purpose pastes), are used preferably for heavy vinyl — and metal-faced wallpapers.

Light textile fabric wallcoverings are hung with special fabric wallcovering adhesives. Special-purpose pastes containing 10-20% of emulsion-based adhesives also are used.

Heavy wallcoverings of unbacked PVC (1000 g/m2 or more) can be applied with adhesives based on acrylate or poly(vinyl acetate) copolymer emulsions. The same applies to metal foils that are applied underneath wallpaper as a vapor barrier.

Polystyrene and polyurethane foam and mineral wool tiles are applied to interior and exterior for decoration and insulation purposes (sound and heat). Solventless adhesives based on poly(vinyl acetate), polyacrylate, or styrene — butadiene copolymer emulsions are preferred for this purpose. The viscosity of the adhesives must be adjusted to give the required wet tack.

Подпись:Ceramic wall tiles are applied either with cement mortar adhesives or with adhesives based on styrene — butadiene copolymer or polyacrylate emulsions. Tile adhesives must be pasty and thixotropic to prevent the tiles from slipping but allow positioning.

Wood panels, chipboard, and similar wooden materials can be fixed with aqueous adhesives based on poly(vinyl acetate) or polyacrylate emulsion. The adhesives must be pasty and have high initial strength. In some cases they are applied from cartridges. Also contact adhesives, special reactive systems (hybrid silicone), and hot-melt adhe­sives are utilized.

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